• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Soil effect on the bearing capacity of a double-lining structure under internal water pressure

    2022-11-30 09:51:16DongmeiZHANGXianghongBUJianPANGWendingZHOUYanJIANGKaiJIAGuanghuaYANG

    Dong-mei ZHANG ,Xiang-hong BU ,Jian PANG ,Wen-ding ZHOU ,Yan JIANG ,Kai JIA ,Guang-hua YANG

    1Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China

    2Key Laboratory of Geotechnical and Underground Engineering of Minister of Education,Tongji University,Shanghai 200092,China

    3State Grid Tianjin Electric Power Company Construction Branch,Tianjin 300143,China

    4Guangdong Research Institute of Water Resources and Hydropower,Guangzhou 510610,China

    5School of Water Conservancy Engineering,Zhengzhou University,Zhengzhou 450001,China

    Abstract: Water conveyance tunnels usually experience high internal water pressures and complex soil conditions.Therefore,shield tunnels with double-lining structure have been adopted because of their high bearing capacity.The effect of the interface between the segmental and inner linings on the bearing capacity has been widely investigated;however,the effect of soil on the internal water pressure bearing capacity has not been emphasized enough.Therefore,in this study,model tests and an analytical solution are presented to elucidate the effect of soil on the internal water pressure bearing capacity.First,model tests are conducted on double-lining models under sandy soil and highly weathered argillaceous siltstone conditions.The internal force and earth pressure under these different soil conditions are then compared to reveal the contribution of soil to the internal water pressure bearing capacity.Following this,an analytical solution,considering the soil–double-lining interaction,is proposed to further investigate the contribution of the soil.The analytical solution is verified with model tests.The analytical solution is in good agreement with the model test results and can be used to evaluate the mechanical behavior of the double-lining and soil contribution.The effect of soil on the bearing capacity is found to be related with the elastic modulus of the soil and the deformation state of the double-lining.Before the double-lining cracks,the sandy soil contributes 3.7% of the internal water pressure but the contribution of the soil rises to 10.4% when it is the highly weathered argillaceous siltstone.After the double-lining cracks,the soil plays an important role in bearing internal water pressure.The soil contributions of sandy soil and highly weathered argillaceous siltstones are 10.5% and 27.8%,respectively.The effect of soil should be considered in tunnel design with the internal water pressure.

    Key words: Shield tunnel;Double-lining;Bearing capacity;Soil condition;Internal water pressure

    1 Introduction

    Water conveyance tunnels have gained wide pop‐ularity in engineering applications owing to the scar‐city of water resources in metropolitan areas.Due to long-distance water diversion and shortage of under‐ground space in urban areas,water conveyance tun‐nels are deeply buried and consequently experience high internal water pressure and complex surrounding soil conditions (Huang et al.,2019,2020;Zhang JZ et al.,2021).Therefore,a shield tunnel with doublelining structure has been proposed.The shield method presents advantages such as fast construction speeds and minimal disturbance to the surrounding soil (Li et al.,2021;Huang et al.,2022a,2022b).The doublelining structure is composed of segmental and rein‐forced concrete inner linings and demonstrates a higher bearing capacity compared with a monolayer-lined str?ucture (Takamatsu et al.,1992;Guo CX et al.,2019;Zhai et al.,2020).

    Fig.1 Loading system designed for the model test under internal water pressure conditions: (a) system composition;(b)water bladder;(c)distribution frame

    The bearing capacity of a shield tunnel with a double-lining structure under internal water pressure has attracted considerable research attention and rese?archers have suggested that the interface between the outer segmental lining and the inner lining is a key factor influencing its bearing capacity(Su and Blood‐worth,2016;Liu et al.,2019).Before the inner lining is cast in-situ,the inner surface of the segmental lining can be treated with by a different construction method,such as chiseling,spreading waterproofing membrane,or embedding steel bars.Consequently,the ability of the lining–lining interface to transform shear and nor‐mal forces varies and exerts an influence on the bearing capacity of the double-lining.Some researchers have proposed lining–lining interface models to describe the mechanical property of the lining–lining interface.The lining–lining interface construction method influ‐ences the smoothness of the interface.International Tunnelling Association (ITA) (Working Group No.2,International Tunnelling Association,2000) suggested that only the normal force can be transmitted through the lining–lining interface when the interface is smooth.When the interface is uneven or dowelled jointing,both normal and shear forces can be transmitted through it.Further,Zhang et al.(2001a,2001b) and Yan et al.(2015)proposed radial and tangential springs to simu‐late the ability of the lining interface to transmit nor‐mal and shear forces.Based on the lining–lining inter‐face model,the mechanical behavior of the doublelining structure has been investigated (Song et al.,2018;Chen et al.,2020;Zhang XD et al.,2021).Wang et al.(2019a,2019b) conducted the model tests for double-lining possessing different interface types.The results indicated that when the lining–lining interface can transmit both the normal and shear forces,the maximum displacement of double-lining is smaller and failure occurs later.Yang et al.(2018)simulated the lining–lining interface using springs in their 3D finite element models.The results suggested that,as the compression stiffness of normal springs decreased,less internal water pressure was transmitted to the segmen‐tal lining.

    The research described above has paid most atten‐tion to the effect of the lining–lining interface proper‐ty on the bearing capacity of double-lining and,so far,the effect of surrounding soil has been conventionally regarded as an external load.The stress distribution of soil under internal water pressure has been studied for that high minimum principal stresses of soil would lead to the hydraulic fracture of soil and to local water losses(Schleiss,1997;Simanjuntak et al.,2014;Zhou et al.,2015).In fact,the soil also provides resistance to constrain tunnel deformation under internal water pressure,but this effect of soil on bearing internal water pressure has been ignored.

    In this study,considering the soil–double-lining interaction,the bearing capacity of the double-lining structure under internal water pressure is investigated through model tests and an analytical solution.First,double-lining model tests under sandy soil and highly weathered argillaceous siltstone conditions are con‐ducted.A double-lining model is specifically designed to simulate its performance under internal water pres‐sure.By comparing the behavior of the double-lining model under different soil conditions,the contribution of soil to the bearing capacity of the double-lining is analyzed.Subsequently,an analytical solution for the soil–double-lining interaction under internal water pres‐sure is proposed and verified against the model test results.The bearing contribution of soil to the internal water pressure is found to be closely related to the elastic modulus of the soil.

    2 Design of the model test

    2.1 Loading system and loading process

    Figs.1 and 2 present the loading system designed for the model test.The loading system consisted of a model box with external earth pressure and internal water pressure loading devices.The model box was 1.8 m high,2.0 m wide,and 0.4 m thick internally.Two transparent Perspex plates with square shapes and a dimension of 0.8 m×0.8 m were placed in the middle of the model box to enable convenient observation dur‐ing the loading process.A circular opening was made in the middle of the transparent Perspex plate to facili‐tate the entry of water bladder into the tunnel.

    Three hydraulic jacks were set above the soil to simulate the external earth pressure acting on the shield tunnel buried 50 m deep.A distribution frame with a high bending stiffness was designed to transform the point load into a distribution load.The internal water pressure loading device included a water bladder,water pressure pump,and automatic pressure controller.The water bladder was composed of an elastic latex mem‐brane,steel cover plates,and steel sealing rings.After the water bladder was filled with water,the internal water pressure was transmitted to the inner surface of the tunnel lining through the latex membrane.The water bladder was 420 mm in length,longer than that of the tunnel,to ensure that the water pressure was uniform along the tunnel.

    The loading process involved two steps.First,external earth pressure was loaded through the hydrau‐lic jacks.The buried depth of tunnel crown was 50 m and the corresponding earth pressure was 900 kPa.In order to study the mechanical behavior of doublelining under different loads,the external earth pres‐sure was loaded to 360,720,and 900 kPa step by step.Each earth pressure step was kept stable for 30 min until the movement of soil stopped.The internal water pressure was increased by 0.01 MPa until the failure of the double-lining structure.Each water pressure step was kept for 5 min until the soil deformation reached stability.

    2.2 Similarity relation

    It has been established that a physical quantity is required to follow the similarity relation between a pro‐totype and a model.In this model test,the similarity ratios of geometryCLand unit weightCγwere selected as the basic similarity ratios.CLwas determined to be 1:20 by considering the boundary effect of the model box and the size of the tunnel model.In the 1gexper‐imental condition(gdenotes the acceleration of grav‐ity),the similarity ratio of unit weightCγwas deter‐mined to be 1:1.The similarity ratios for other quanti‐ties were similarly determined,and the values obtained are presented in Table 1.

    Table 1 Similarity ratios in this model test

    Fig.2 Schematic of the model box(unit:mm)

    2.3 Modelling of double-lining

    Fig.3 presents a cross-sectional view of the pro‐totype shield tunnel.As can be observed,the doublelining structure is composed of a segmental lining,an inner lining,and a waterproof membrane.The seg‐mental lining consists of one key block(F),two adja‐cent blocks (L1 and L2),and four standard blocks(B1–B4).The external radius of the segmental lining is 4.15 m,and the inner radius is 3.75 m.The con‐crete type used is C55,and the width of the segment is 1.60 m.The inner lining is cast in place using C50 grade concrete.The inner diameter of the inner lining is 6.4 m.A 1.2 mm-thick waterproof membrane is spread between the segmental and inner linings to enhance the waterproofing ability of the tunnel.

    Fig.3 Prototype of the shield tunnel with a double-lining structure(unit:mm)

    Fig.4 presents the 3D and cross-sectional views of the double-lining model.The model test was desig?ned to investigate the behavior of double-lining in the cross-section.The earth pressure,internal water pres‐sure,and the soil were kept identical along the longi‐tudinal direction.For the double-lining structure,the segmental lining was a staggered assembly with a 38°rotational shift to the adjacent rings.Therefore,four rings of tunnel of 0.4-m length are two cycles of the staggered installation of the segmental lining and can represent the double-lining structure.To simulate the mechanical response of the double-lining structure under internal water pressure,the lining material,joint configuration,and lining interface were specifically designed.

    Fig.4 Schematic of the double-lining model: (a) 3D view;(b)cross-sectional view(unit:mm)

    2.3.1 Similar materials for the linings

    The concrete of the segmental and inner linings was simulated using gypsum mortar.Gypsum mortar is a mixture of gypsum,water,and diatomite.It is necessary for the concrete and gypsum mortar to sat‐isfy the similarity ratios of elastic modulus and com‐pressive strength.Therefore,uniaxial compressive strength tests were conducted on gypsum mortar spec‐imens containing different gypsum contents.The test results are presented in Fig.5.Based on the similarity ratio,a gypsum mortar mixed with water,gypsum,and diatomite in a ratio of 1.0:1.4:0.1 was adopted for the segmental lining and one with a ratio of 1.00:1.35:0.10 was adopted for the inner lining.The mechanical para?meters of the segmental and inner linings are presented in Table 2.

    Fig.5 Test results for the gypsum mortar: (a) uniaxial compressive strength;(b)elastic modulus

    Table 2 Mechanical properties of the double-lining

    Iron wire was used to simulate the rebar in the segmental and inner linings.In the presence of inter‐nal water pressure,the lining is expected to crack under the action of the tensile force produced in the lining.After the lining cracks,the rebar primarily bears the tension.Therefore,the arrangement of the iron wire was that the similarity ratio of axial stiffnessCEA(1:203) was obeyed.The elastic modulus of the iron wire and rebar is 200 GPa.The reinforcement ratio of the segment in the prototype is 0.9%.Therefore,two iron wires with diameters of 0.8 mm were arranged in each segmental lining.The reinforcement ratio of the inner lining in the prototype was 2.3%.Accordingly,16 rings of iron wires with diameters of 1.0 mm were set in the inner lining of the model.

    2.3.2 Modelling of the segmental joint

    Simulating a segmental circumferential joint is one of the primary challenges faced during the execu‐tion of the model test.Wang et al.(2019a,2019b)and Guo R et al.(2019) proposed the creation of grooves at the joint position in the gypsum mortar ring.This method could effectively simulate the bending stiff‐ness of the joint.However,it is not reasonable to sim‐ulate the tension capacity of the joint accurately.Under the effect of internal water pressure,the joint is under tension and bears the existing load through bolts.In this condition,the gypsum mortar ring with grooves cracks and cannot withstand the tension.To overcome this shortcoming,a novel approach for modelling the segmental joints was proposed.As shown in Fig.6,the joint model was composed of two iron pieces,two iron rods,two screws,and an iron wire.To simulate the mechanical behaviour of a real joint,the bending stiffness and tension stiffness of the joint should satisfy a similar relation between the model and prototype.The iron rods were set at the hole of the iron plates to simulate the bending stiffness of the joint.The geo‐metric size of the iron rod was determined through a similar relation of bending stiffness,and the bending stiffness of the joint was obtained by numerical simu‐lation.The diameter and length of the iron rod were 1.6 and 25.0 mm,respectively.The iron wire was set to simulate the tension capacity of the joint,fixed at the external surface of segment by a screw.The iron wire of the model and the bolt of the prototype should satisfy a similar relation of tension stiffness coefficient,as shown in Eq.(1).

    Fig.6 Detailed illustration of the circumferential joint:(a)3D view;(b)cross-sectional view

    whereE,A,andlrefer to the elastic modulus,area,and length,and subscripts m and p refer to the iron wire and bolt,respectively.A=πD2/4,andDrefers to the diameter.Ckrefers to the similarity ratio of the ten‐sion stiffness coefficient and is equal to 1:202.In this study,Ep=Em=200 GPa,Dp=36 mm,andlp=435 mm.Thus,the iron wire was adopted asDm=0.6 mm andlm=30 mm.

    2.3.3 Modelling of the lining–lining interface

    According to ITA(Working Group No.2,Inter‐national Tunnelling Association,2000),the doublelining structure can be divided into a double-shell structure and the composite structure based on the lining–lining interface smoothness.For the doubleshell structure,the interface is relatively smooth,and only the normal force can be transmitted through the interface.For the composite structure,the interface undergoes chiselling,grooving,or embedding rebars.Both the normal and shear forces can be transmitted through the interface.For the shield tunnel subjected to internal water pressure,laying a waterproof mem‐brane between the inner and segmental linings is gen‐erally essential.The surface of the waterproof layer then becomes smooth,and the tunnel can be con‐sidered as a double-shell structure.Therefore,in the model test,a smooth plastic film was set inside the seg‐mental lining to simulate the interface with a water‐proof layer,as shown in Fig.7.

    Fig.7 Modelling of the lining–lining interface

    2.4 Modelling of soil

    Under the effect of internal water pressure,the shield tunnel deforms outwards,and soil provides the necessary resistance to constrain the resulting tunnel deformation.The tunnel lining and the surrounding soil collectively bear the internal water pressure.The soil resistance is closely related to the elastic modulus of the soil.The elastic modulus must satisfy the similar‐ity ratio.To investigate the influence of the soil condi‐tion on the bearing capacity of the double-lining struc‐ture,two types of soils were prepared: sandy soil and highly weathered argillaceous siltstone.Sandy soil was simulated using a material composed of barite powder,plastic foam,glass sand,and glycerol.Plastic foam,glass sand,and glycerol were mixed in a volume ratio of 1.0:1.0:0.5.Following this,barite powder was combined with the mixture in a mass ratio of 1:1.The highly weathered argillaceous siltstone condition was simulated using river sand.Through geotechni‐cal tests,the elastic modulus of sandy soil and highly weathered argillaceous siltstone were determined to be 2.5 and 50.0 MPa,respectively,which corresponded to the respective values of 50 MPa and 1 GPa in the prototype.

    2.5 Layout of measurement

    To evaluate the mechanical behaviour of doublelining tunnels under the effect of internal water pres‐sure,the lining internal force and earth pressure acting around the tunnel were measured,as shown in Fig.8.For this,strain gauges were arranged at 12 different sections around the circumference and are denoted as S1–S12.The strain gauges were installed on the outer and inner surfaces of the double-lining and lining–lining interface at every section.These strain gauges were used to calculate the internal force acting on the segmental and inner linings.Additionally,earth pres‐sure cells were installed at 45° intervals on the soil–lining interface and are denoted as P1–P8.

    3 Test results and analysis

    In this section,the internal force and earth pres‐sure under different soil conditions were compared to investigate the effect of soil on the bearing capacity of the double-lining structure.Also,the failure mode of the double-lining structure under high internal water pressure was analysed.The bending moment and axial force can be obtained using Eq.(2).

    whereMandNare the bending moment and axial force,respectively;ε1andε2are the strains at the exter‐nal and inner surfaces of the segmental and inner lin‐ings,respectively;bandhare the width and thickness of the segmental and inner linings,respectively.

    3.1 Internal force

    3.1.1 Bending moment

    Fig.9 illustrates the variation of bending moment with the internal water pressure under the sandy soil and highly weathered argillaceous siltstone conditions.As can be observed,the variation of bending moment due to a change in the internal water pressure was min‐imal under both the sandy soil and highly weathered argillaceous siltstone conditions.For the segmental lining,the variation of bending moment was mostly less than 50 kN·m,except at the invert under sandy soil conditions.For the inner lining,the largest varia‐tion can be observed at the invert under highly weath‐ered argillaceous siltstone conditions,which exceeded 100 kN·m.The variation of bending moment at other positions was within 100 kN·m.Thus,it can be con‐cluded that the bending moment changes slightly dur‐ing internal water pressure loading regardless of the soil condition.

    Fig.9 Bending moment under different soil conditions:(a) segmental lining;(b) inner lining.Soil A: sandy soil;Soil B:highly weathered argillaceous siltstone

    3.1.2 Axial force

    Fig.10 illustrates the variation of axial force with the internal water pressure under sandy soil and highly weathered argillaceous siltstone conditions.It can be observed that the variation trend followed by the axial force under the sandy soil and highly weathered argillaceous siltstone conditions was similar.When the earth pressure loading was completed and internal pressure was not applied,the axial force acting on the lining was compressed.With an increase in the inter‐nal water pressure,the axial force acting on the seg‐mental and inner linings decreased and developed into tension.The tensile strength of concrete is signifi‐cantly lower than its compressive strength.Thus,ten‐sile cracks may appear at the double-lining structure.The magnitude of compression at the crown and invert was relatively small compared with that at the spring before the loading of internal water pressure.There‐fore,the lining at the crown and invert is more prone to crack formation under the effect of internal water pressure.

    Fig.10 Axial forces under different soil conditions:(a)segmental lining;(b)inner lining

    However,the variation rate of axial force under the sandy soil condition was found to be larger than that under the highly weathered argillaceous siltstone condition.Considering the segmental lining as an example,the axial force acting at the crown under the sandy soil condition changed from 381.4 to ?176.5 kN with an increase in the internal water pressure.The decrement of the axial force was 557.9 kN under the sandy soil condition,which was 18% larger than that observed under the highly weathered argillaceous silt‐stone condition.As the elastic modulus of soil decre?ases,the surrounding soil provides less resistance and,consequently,more internal water pressure is borne by the double-lining.In general,under internal water pressure,the axial force acting on the double-lining decreased significantly,whereas the bending moment changed only slightly.The double-lining deforms out‐wards under the internal water pressure.The radial dis‐placement of double-lining is nearly the same along the circumferential direction.Thus,the double-lining is under tension and no bending deflection occurrs.The axial force changes significantly while the bending moment changes slightly.The variation rate of the axial force can reflect the sharing ratio of internal water pressure for the double-lining under different soil conditions.The variation rate of axial force for the double-lining structurekNis defined in Eq.(3),and it was 3218 kN/MPa under the sandy soil condition,and 2111 kN/MPa under the highly weathered argilla‐ceous siltstone condition,which indicated that the sharing ratio of internal water pressure for the doublelining decreased by 35.40%.

    where ΔNis the variation of axial force acting on the double-lining,andpwis the internal water pressure.

    By comparing the variation of axial force between the segmental lining and inner lining,it can be con‐cluded that the axial force decrement for the inner lin‐ing is significantly more than that for the segmental lining.Under the highly weathered argillaceous silt‐stone condition,the axial force decrement for the seg‐mental lining at the crown was 473 kN and that for the inner lining was 1418 kN.The axial force decre‐ment for the inner lining was 3.0,2.8,and 2.1 times more than that for the segmental lining at the crown,spring,and invert,respectively.The axial force decre‐ment is used to measure the sharing ratio of internal water pressure between the segmental and inner lin‐ings,as shown in Eq.(4).The sharing ratio between the segmental and inner linings was 1.0:2.7 and 1.0:2.6 under the sandy soil and highly weathered argillaceous siltstone conditions,respectively.The sharing ratio between the segmental and inner linings is not rele‐vant to the soil condition;however,it is relevant to the lining stiffness.The segmental lining demonstrates low axial stiffness owing to the existence of joints.The inner lining plays an important role in internal water pressure bearing.Thus,the inner lining is more prone to damage under the effect of internal water pressure.

    whereλrefers to the sharing ratio of internal water pressure between the segmental and inner linings,and ΔNsand ΔNirefer to the axial force decrement observed for the segmental and inner linings,respectively.

    3.2 Earth pressure

    3.2.1 Variation in earth pressure under the highly weathered argillaceous siltstone condition

    The variation of earth pressure under the highly weathered argillaceous siltstone condition was anal‐ysed.Fig.11 presents the development of earth pres‐sure during external soil loading.It can be observed that the earth pressure increased as the external soil load was imposed.The overburden increased to 20,40,and 50 m in three steps.The corresponding earth pressure increments at the crown are denoted as Δ1,Δ2,Δ3,respectively.The quantitative relationship can be presented as Δ1≈Δ2≈2Δ3≈340 kPa.After the com‐pletion of loading,the earth pressure reached 815 kPa at the crown and 883 kPa at the invert.The earth press?ures at the left and right springs were 377 and 469 kPa,respectively.The lateral earth pressure coefficient was 0.45 in the model test.

    Fig.11 Variation of earth pressure with external soil load

    Fig.12 presents the variation of earth pressure with the increase of internal water pressure.From the figure,it can be observed that the double-lining struc‐ture has undergone the following three stages under the effect of internal water pressure.First,when the internal water pressure was less than 0.4 MPa,the double-lining structure was in the elastic stage.The earth pressure increased almost linearly with the inter‐nal water pressure.Second,when the internal water pressure reached 0.4 MPa,the double-lining cracked and subsequently entered the damage stage.The earth pressure still followed a linear trend;however,the rate of increase of earth pressure in the damage state was visibly larger than that observed in the elastic state.Finally,when the internal water pressure incre?ased to 0.97 MPa,the double-lining structure entered a failure stage.At this stage,the joint opening increased sharply and the joint eventually fractured.The seg‐mental lining deformed outward continuously at a con‐stant internal water pressure and,consequently,the double-lining structure lost its bearing capacity.

    Fig.12 Variation of earth pressure with internal water pressure

    To compare the soil resistance when the doublelining is in the elastic and damage states,the variation rate of earth pressure with internal water pressure,ki,is defined as shown in Eq.(5),and the results are pre‐sented in Table 3.The variation rate of earth pressure in the damage stage was approximately 3.0 times of that in the elastic stage at the crown and invert,and it was 2.0 times of that in the elastic stage at the left and right springs.When the double-lining cracks,the axial ten‐sile stiffness of the double-lining is reduced.Therefore,the surrounding soil has to bear more internal water pressure.Moreover,the axial forces at the crown and invert are less than those at the spring.Thus,the tensiledamages at the crown and invert are more severe.Consequently,the variation rate of earth pressure incr?eases more significantly at the crown and invert.

    Table 3 Variation rate of earth pressure with internal water pressure

    wherei=1,2 refers to the elastic and damage stages,respectively;ΔSiand Δpwirefer to the increments in earth pressure and internal water pressure during the corresponding stage represented byi.

    3.2.2 Comparison of earth pressure under different soil conditions

    Fig.13 illustrates the variation in earth pressure under the sandy soil and highly weathered argillaceous siltstone conditions.During the loading process of internal water pressure,the double-lining under the sandy soil condition experienced the following three stages: elastic stage,damage stage,and failure stage.When the internal water pressure reached a crack‐ing point of 0.33 MPa,the double-lining was in the damage stage,and the variation rate of earth pressure increased.When the internal water pressure reached 0.70 MPa,the joint opening increased sharply and the double-lining failed.However,the increment in the earth pressure under the sandy soil condition was obvi‐ously less than that under the highly weathered argilla‐ceous siltstone condition.This result indicates that the soil resistance effect demonstrated in the highly weath‐ered argillaceous siltstone condition is significantly higher than that demonstrated in the sandy soil condi‐tion,which improves the overall internal pressure bear‐ing capacity of the soil-lining structure.

    Fig.13 Earth pressure under different soil conditions

    To investigate the contribution of soil and its influence on the bearing capacity of the double-lining,the contribution of soil to the internal water pressure is defined as the ratio of the increment in the earth pressure to the internal water pressure,as shown in Eq.(6).Fig.14 presents the change in the contribution of soil to the internal water pressure.It can be observed that the contribution of soil to the internal water pres‐sure increased slowly during the elastic stage,where‐as it increased rapidly during the damage stage.Dur‐ing the elastic stage,the highly weathered argillaceous siltstone condition contributed 10.4% of the internal water pressure,while the contribution of the sandy soil was only 3.7%.Compared with sandy soil,the contribution of highly weathered argillaceous siltstone was enhanced by only a small margin.Therefore,the cracking point of the double-lining rose slightly from 0.33 to 0.40 MPa.During the damage stage,the con‐tribution to the bearing capacity reached 27.8% for highly weathered argillaceous siltstone and 10.5% for sandy soil.Thus,the contribution of the highly weath‐ered argillaceous siltstone condition was substantially higher than that of the sandy soil condition.Conse‐quently,the ultimate bearing capacity of the doublelining structure increased from 0.70 to 0.97 MPa with a large amplitude when the soil type changed from sandy soil to highly weathered argillaceous siltstone.Thus,the contribution of soil to the internal water pressure increased when the elastic modulus of soil improved,which is beneficial to the joint bearing capacity of the soil-lining.

    Fig.14 Contribution of soil under different soil conditions

    whereηrefers to the contribution of soil to the inter‐nal water pressure,and ΔSrepresents the increment in earth pressure during internal water pressure loading.

    3.3 Failure mode

    As the internal water pressure increased,tensile cracks continued to appear in the double-lining.The failure characteristics of the double-lining structure were similar under both the sandy soil and highly weathered argillaceous siltstone conditions.The doublelining model after failure under the highly weathered argillaceous siltstone condition is analysed.Fig.15 shows the crack distribution in the double-lining struc‐ture for the final failure state.As can be observed,for the segmental lining,cracks appeared at the crown,spring,and invert.Multiple longitudinal cracks occur?red at the crown and invert,whereas the number of cracks at the left and right springs was relatively small.For the inner lining,the crack distribution was similar to that of the segmental lining.Cracks were primarily concentrated at the areas of the crown and invert.Dur‐ing the loading of internal water pressure,cracks first appeared at the crown,then at the invert,and finally at the left and right springs.Figs.16 and 17 present the corresponding images for the segmental and inner lin‐ings after failure,respectively.The crack widths at the crown,right spring,invert,and left spring are denoted asD1,D2,D3,andD4,respectively.For the segmental and inner linings,the crack width relationship can be expressed asD1≈D3>D4>D2.Thus,it can be concluded that the damage at the crown and invert was more severe.The development of cracks was closely related to the internal force acting on the tunnel,which has been introduced in Section 3.1.The axial force at the crown and invert changed to tension earlier than that at the spring.Consequently,cracks first occurred at the crown and invert.As the internal water pressure increased,the crack number and width at the crown and invert correspondingly increased,and the result‐ing damage was more severe.

    Fig.15 Crack distribution in the double-lining structure:(a)segmental lining;(b)inner lining

    From Figs.16 and 17,it can be observed that the crack width at the inner lining was larger compared with that at the segmental lining.Additionally,the cracks on the inner lining were mostly longitudinal cracks.This can be attributed to the fact that the inner lining bears a higher proportion of the internal water pressure,which causes severe damage to the inner lin‐ing structure.

    The double-lining structure failed in the final stage owing to the occurrence of a joint fracture.As can be observed from Fig.16,the joint fractured and was incapable of withstanding any more tension.More‐over,the cracks in the segmental lining mostly app?eared near the joint of the adjacent ring.It can be seen that the cracks in the inner lining usually occurred near a segmental joint.This phenomenon indicates that the segmental joint possesses lower axial stiffness and ten‐sile strength.Thus,the segmental joint can be thought of as a weak-point in the double-lining structure.

    Fig.16 Object image of the segmental lining after failure:(a)crown;(b)right spring;(c)invert;(d)left spring

    In summary,we can conclude that cracks are mostly distributed at the crown and invert near a seg‐mental joint,and more severe damage appears on the inner lining.Thus,the crack width at the crown and invert of the inner lining and close to the segmental joint must be emphasized during the design phase.

    Fig.17 Object image of the inner lining after failure:(a)crown;(b)right spring;(c)invert;(d)left spring

    4 Analytical solution

    The model test results indicate that the contribu‐tion of soil to the internal water pressure is crucial to the bearing capacity of the double-lining.The contri‐bution of soil is related to the elastic modulus of the soil.To show further the variation of the soil contribu‐tion to the internal water pressure with the elastic mod‐ulus of the soil,an analytical solution for the doublelining under the effect of internal water pressure is pro‐posed.For this,the segmental and inner linings are assumed to be thick-walled cylinders.The axial stiff‐ness of the segmental lining is affected owing to the existence of joints and the axial stiffness of the inner lining reduces after cracking,which is considered in the analytical solution.

    4.1 Analytical model for the interaction between soil and double-lining

    4.1.1 Mechanical model

    Fig.18 depicts a mechanical model of the doublelining under the effect of internal water pressure.The double-lining is embedded in an infinite elastic layer of soil.As mentioned earlier,the segmental and inner linings are assumed to be thick-walled cylinders.The elastic modulus and Poisson’s ratio of the soil,seg‐mental lining,and inner lining are denoted asE0,E1,E2,v0,v1,andv2,respectively.Moreover,the outer and inner radius of the segmental lining are denoted asr0andr1,respectively,while the inner radius of the inner lining is denoted asr2.

    Fig.18 Mechanical model of the double-lining under internal water pressure.ρ is the radius;θ is the angle

    4.1.2 Derivation of the analytical solution

    It is known that the internal water pressurepwis borne by the segmental and inner linings and the soil layer.As shown in Fig.19,the pressures transmitted to the segmental lining and soil are assumed to beP1andP2,respectively.

    Fig.19 Load distribution for the tunnel and soil layer

    The inner lining,segmental lining,and soil layer can be solved using the Lame solution.According to the Lame solution,the radial displacement function is given as

    whereu0,u1,andu2refer to the radial displacement of the soil layer,segmental lining,and inner lining,respectively.

    The radial displacements at the lining–lining interface and soil–lining interface satisfy displacement coordination,as shown in Eq.(8).Further,Eq.(8)can be transformed into a matrix form,and the interface pressure can be solved,as shown in Eq.(9).

    Then,the stress of segmental and inner linings can be solved according to the Lame solution.The maximum circumferential normal stress occurs at the inner surface of the inner lining,which can be used to determine the cracking load of the double-lining,as shown in Eq.(10).

    whereσθ2refers to the circumferential normal stress acting on the inner lining.

    4.1.3 Elastic modulus of the segmental and inner linings

    As mentioned earlier,the segmental lining is assumed to be a homogeneous thick-walled cylinder.However,the axial stiffness of the circumferential joint is different from that of the segment.Thus,an equiva‐lent elastic modulus was calculated to represent the axial stiffness of the entire segmental lining.As shown in Fig.20,the segmental lining can be regarded as a tandem system composed of segments and joints under tension.The circumferential displacement of the seg‐mental lining is equal to the sum of the circumferen‐tial displacement of the segment and that of the joint,as shown in Eq.(11).Therefore,the equivalent elastic modulus of the segmental lining can be derived as shown in Eq.(12).

    Fig.20 Schematic of the segmental lining

    whereT1represents the tensile force acting on the seg‐mental lining;Es,As,andlsdenote the elastic modulus,area,and length of the segment,respectively;Ejb,Ajb,andljbrepresent the elastic modulus,area,and length of the joint bolt,respectively.

    After the inner lining cracks,its axial stiffness red?uces.The Comité Euro-International du Beton (CEB)model was proposed to describe the mechanical behav‐iour of reinforced concrete subjected to tension in terms of an average strain (CEB,1985;Stramandinoli and La Rovere,2008).The average strain of reinforced concrete with cracks is shown in Eq.(13).Therefore,the axial stiffness of the inner lining after cracking can be derived by Eq.(14).

    whereε2mrepresents the average strain on the inner lining;εrrepresents the strain in the rebar at a cracked section;Δεcrepresents the contribution of concrete between cracks due to its bond with the rebar;Δεc,maxrepresents the contribution of concrete at the begin‐ning of the cracking process;T2represents the tensile force acting on the inner lining;T2crrepresents the ten‐sile force of the inner lining when cracking;A2repre‐sents the area of the inner lining;ErandArdenote the elastic modulus and area of the rebar in the inner lin‐ing,respectively;EcandAcrepresent the elastic modu‐lus and area of concrete in the inner lining,respec‐tively;refers to the elastic modulus of inner lining after cracking.

    4.2 Verification of the analytical solution

    The analytical solution is verified with the model test conducted under the highly weathered argillaceous siltstone condition.The earth pressures obtained from the model test and analytical solution are compared,as shown in Fig.21.As can be observed,the earth pres‐sures obtained from the model test and analytical solu‐tion are similar,with an average deviation of 7.86%.The cracking point derived by the analytical solution lies at 0.35 MPa,which is close to the cracking point of 0.40 MPa obtained from the model test.

    Fig.21 Comparison between model test and theoretical results

    4.3 Effect of soil on the tunnel capacity

    The variation in the contribution of soil to the internal water pressure with the internal water pressure is illustrated in Fig.22.When the double-lining is in the elastic stage,the soil contribution remains stable.After the inner lining cracks,the soil contribution rises and becomes steady with the increase in internal water pressure.For a tunnel lining subjected to internal water pressure,there exist two safety control standards to be followed during the design.First,the cracking point of the lining is selected as a safety control standard.Sec‐ond,the inner lining is allowed to crack,and the radial displacement of the double-lining is selected as a safety control standard to limit the crack width and joint opening.Therefore,both soil contributions,under the elastic and damage stages,are useful in the design of double-linings.

    Fig.22 Variation of soil contribution with internal water pressure

    The variation in the soil contribution to the inter‐nal water pressure with the elastic modulus of soil is presented in Fig.23.As the elastic modulus of the soil increases,the soil contribution rises;however,the rate of increase declines.When the elastic modulus of soil is 50 MPa,the soil contribution under the elastic stage is only 1%,and the soil has little effect on the bearing capacity of the double-lining.The soil contribution under the elastic stage reaches 19.2%when the elastic modulus of soil is 3 GPa.When the double-lining is designed based on the strength control standard,it is suggested that the soil contribution should be consid‐ered as the elastic modulus of soil with a value greater than 3 GPa.When the elastic modulus of soil is below 3 GPa,the soil contribution can be used as a reserve of structural safety.Soil contributes to 2.5%of the inter‐nal water pressure during the damage stage when the elastic modulus is 50 MPa.When the elastic modulus increases to 500 MPa,the soil contribution reaches 19.1%.When the double-lining is designed using the deformation control standard,the soil contribution must be calculated as the elastic modulus of soil with a value greater than 500 MPa.

    Fig.23 Variation of soil contribution with the elastic modulus of soil

    4.4 Discussion of soil contribution

    The results of model tests and analytical solution showed that the contribution of soil on the tunnel bear‐ing capacity increases with an increase of the soil elas‐tic modulus.Consequently,the internal water pressure controlled by double-lining decreases,and the doublelining design can be optimized.Since the inner lining plays a vital role on bearing internal water pressure,the thickness of the inner lining is selected as the opti‐mized design parameter.Under the designed internal water pressure,the thickness of inner lining can be optimized based on the strength or deformation safety control standard.

    Fig.24a shows the thickness of inner lining given the variation of the soil contribution based on the str?ength safety control standard.It can be observed that the thickness of the inner lining decreases linearly as the soil contribution increases.Taking the internal water pressures of 0.3,0.4,and 0.5 MPa as the exam‐ple,when the soil contribution increases from 0 to 50%,the thickness of the inner lining decreases from 0.53 to 0.22 m,from 0.69 to 0.29 m,and from 0.86 to 0.36 m,respectively.The thickness of the inner lining is decreased by about 59%.Furthermore,the reduc‐tion in the thickness of the inner lining is independent of the internal water pressure.The soil contribution can decrease the thickness of the inner lining very signifi‐cantly.In addition,when the soil contribution increases to approximately 90%,the thickness of the inner lin‐ing can be reduced to zero,which means the segmen‐tal lining is enough to bear internal water pressure and there is no need for an inner lining.Fig.24b shows the variation of thickness of the inner lining with soil contribution based on the deformation control stan‐dard.In this case,the inner lining is allowed to crack,and a joint opening of 2 mm is selected as the defor‐mation control standard.The thickness of the inner lining decreases linearly with soil contribution as well.When the soil contribution increases to 80%,the inner lining is no longer necessary.

    Fig.24 Thickness of inner lining given the variation of soil contribution: (a) strength control standard;(b) deformation control standard

    5 Conclusions

    In this study,model tests are conducted to inves‐tigate the mechanical responses of double-lining struc‐tures under the conditions of sandy soil and of highly weathered argillaceous siltstone.The soil contribution and its influence on the bearing capacity of the doublelining structure are analyzed.An analytical solution for the double-lining structure is proposed to further inves‐tigate the variation in the soil contribution to the inter‐nal water pressure with the elastic modulus of the soil.The following conclusions can be drawn from the results of the model test and the analytical solution.

    (1)The double-lining model is designed in terms of similar material,circumferential joint,and lining–lining interface.The double-lining model is similar to the prototype in its tension stiffness and can simulate the mechanical behaviour of double-lining during the elastic and damage stages.

    (2)The proposed analytical solution takes into account the axial stiffness of the segmental lining influ‐enced by the circumferential joint and the reduced axial stiffness of the inner lining after cracking.The average error between the model test and the analytical solution is approximately 7.9%,which verifies the accuracy of the proposed analytical solution.The ana‐lytical solution can reflect the interaction between soil–double-lining and the contribution of soil.

    (3)Before the double-lining cracks,the contribu‐tion to the bearing capacity of the tunnel is 3.7%for the sandy soil;it increases to 10.4%for the highly weath‐ered argillaceous siltstone.As a result,the double-lining cracks when the internal water pressure is 0.33 MPa under sandy soil,while it cracks at 0.40 MPa under highly weathered argillaceous siltstone.

    (4)After the double-lining cracks,the soil plays a more vital role in bearing internal water pressure.The contribution increases to 10.5%for the sandy soil,and 27.8% for the highly weathered argillaceous silt‐stone.Thus,the ultimate bearing capacity of doublelining rises from 0.70 to 0.97 MPa when the soil con‐dition changes from sandy soil to highly weathered argillaceous siltstone.

    (5)The contribution of soil to the bearing capacity increases with the elastic modulus of soil.As the elas‐tic modulus of soil increases to 3 GPa in the elastic stage and 500 MPa in the damage stage,the contribu‐tion of soil reaches about 20%,which should be con‐sidered at the design stage.

    Acknowledgments

    This work is supported by the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-07-456 E00051),the National Natural Science Foundation of China (Nos.51978517,52090082,and 52108381),and the Shanghai Science and Technology Committee Program(Nos.21DZ1200601 and 20DZ1201404).

    Author contributions

    Dong-mei ZHANG designed the research.Xiang-hong BU,Jian PANG,and Wen-ding ZHOU conducted the model test for double-lining and processed the corresponding data.Jian PANG and Xiang-hong BU wrote the first draft of the manuscript.Yan JIANG,Kai JIA,and Guang-hua YANG helped to organize the manuscript.Dong-mei ZHANG and Xiang-hong BU revised and edited the final version.

    Conflict of interest

    Dong-mei ZHANG,Xiang-hong BU,Jian PANG,Wending ZHOU,Yan JIANG,Kai JIA,and Guang-hua YANG declare that they have no conflict of interest.

    99riav亚洲国产免费| 国产区一区二久久| 国产97色在线日韩免费| 亚洲av片天天在线观看| 一区二区三区高清视频在线| 国产精品免费一区二区三区在线| 国产精品爽爽va在线观看网站 | 长腿黑丝高跟| 亚洲国产精品成人综合色| 欧美丝袜亚洲另类 | 99国产综合亚洲精品| 久久久国产成人免费| 成人亚洲精品av一区二区| 91九色精品人成在线观看| 一进一出抽搐gif免费好疼| 久久中文看片网| 亚洲aⅴ乱码一区二区在线播放 | 亚洲一卡2卡3卡4卡5卡精品中文| 免费观看精品视频网站| 身体一侧抽搐| 国产一卡二卡三卡精品| 99国产精品一区二区蜜桃av| 国产亚洲欧美精品永久| 无限看片的www在线观看| 99国产极品粉嫩在线观看| 欧美日本中文国产一区发布| 成人手机av| 午夜久久久久精精品| 欧美精品啪啪一区二区三区| 99re在线观看精品视频| 国产精品爽爽va在线观看网站 | 久久草成人影院| 亚洲国产日韩欧美精品在线观看 | 久久久国产精品麻豆| 麻豆国产av国片精品| 国产aⅴ精品一区二区三区波| 亚洲精品一卡2卡三卡4卡5卡| 日韩 欧美 亚洲 中文字幕| 91av网站免费观看| 欧美色欧美亚洲另类二区 | 搡老妇女老女人老熟妇| 日本撒尿小便嘘嘘汇集6| 中文字幕av电影在线播放| 久久久久久免费高清国产稀缺| 国产主播在线观看一区二区| 成人免费观看视频高清| 久久国产乱子伦精品免费另类| 精品国产美女av久久久久小说| 国产av精品麻豆| 久久这里只有精品19| xxx96com| 老司机在亚洲福利影院| 两个人免费观看高清视频| 久久人妻福利社区极品人妻图片| 中文字幕人妻熟女乱码| 日韩一卡2卡3卡4卡2021年| 午夜免费鲁丝| 夜夜看夜夜爽夜夜摸| 啦啦啦免费观看视频1| 日本精品一区二区三区蜜桃| 久久午夜亚洲精品久久| 老司机福利观看| 9191精品国产免费久久| 午夜精品国产一区二区电影| 亚洲中文av在线| 午夜免费激情av| 久久草成人影院| 亚洲av成人一区二区三| 麻豆成人av在线观看| 久久国产精品男人的天堂亚洲| 国产精品爽爽va在线观看网站 | 久久久久久久精品吃奶| 欧美一级毛片孕妇| 超碰成人久久| 一进一出好大好爽视频| cao死你这个sao货| 十分钟在线观看高清视频www| 99精品在免费线老司机午夜| 国产亚洲精品久久久久久毛片| 一进一出好大好爽视频| 久久精品成人免费网站| 国产精品 欧美亚洲| 在线十欧美十亚洲十日本专区| 成人三级黄色视频| 窝窝影院91人妻| 久久精品亚洲熟妇少妇任你| 一区二区日韩欧美中文字幕| 亚洲国产精品成人综合色| 久9热在线精品视频| 欧洲精品卡2卡3卡4卡5卡区| 欧美 亚洲 国产 日韩一| 久久欧美精品欧美久久欧美| 在线天堂中文资源库| 久久香蕉激情| 久久国产亚洲av麻豆专区| 麻豆久久精品国产亚洲av| 久久久国产欧美日韩av| 亚洲天堂国产精品一区在线| 黄色丝袜av网址大全| 极品人妻少妇av视频| 精品熟女少妇八av免费久了| 极品人妻少妇av视频| 黄片播放在线免费| 欧美日韩一级在线毛片| 一卡2卡三卡四卡精品乱码亚洲| 精品卡一卡二卡四卡免费| 手机成人av网站| 精品国产亚洲在线| 亚洲人成网站在线播放欧美日韩| 夜夜看夜夜爽夜夜摸| 精品福利观看| 成人永久免费在线观看视频| 中文字幕av电影在线播放| 中文字幕高清在线视频| 欧美激情久久久久久爽电影 | 国产精品香港三级国产av潘金莲| 精品乱码久久久久久99久播| 亚洲成av片中文字幕在线观看| 一夜夜www| 欧美成人一区二区免费高清观看 | 亚洲情色 制服丝袜| 一级毛片高清免费大全| 麻豆成人av在线观看| 免费av毛片视频| 18美女黄网站色大片免费观看| 国产精品久久视频播放| 三级毛片av免费| 看黄色毛片网站| 国产亚洲精品第一综合不卡| 1024视频免费在线观看| 免费在线观看日本一区| 色在线成人网| 18美女黄网站色大片免费观看| 久久人人爽av亚洲精品天堂| 精品人妻1区二区| 日本a在线网址| 一本久久中文字幕| 热99re8久久精品国产| 91麻豆av在线| 成人特级黄色片久久久久久久| 国产精品二区激情视频| 日本撒尿小便嘘嘘汇集6| 欧美国产精品va在线观看不卡| 亚洲欧美日韩无卡精品| 桃红色精品国产亚洲av| 啦啦啦韩国在线观看视频| 好男人电影高清在线观看| 日韩欧美免费精品| 免费不卡黄色视频| 777久久人妻少妇嫩草av网站| 亚洲激情在线av| 午夜精品在线福利| 91九色精品人成在线观看| 国产一区在线观看成人免费| 一区二区三区精品91| 日日爽夜夜爽网站| 久久国产精品男人的天堂亚洲| 久久精品91无色码中文字幕| 高潮久久久久久久久久久不卡| 999久久久国产精品视频| 国产成年人精品一区二区| 国产成人一区二区三区免费视频网站| 中文字幕高清在线视频| 国产主播在线观看一区二区| 日日干狠狠操夜夜爽| 亚洲人成电影免费在线| 久久人人爽av亚洲精品天堂| 婷婷精品国产亚洲av在线| 亚洲美女黄片视频| 国产成人系列免费观看| 日韩高清综合在线| www.999成人在线观看| 久久亚洲真实| 曰老女人黄片| 99精品欧美一区二区三区四区| 亚洲aⅴ乱码一区二区在线播放 | 人人妻人人爽人人添夜夜欢视频| 久9热在线精品视频| 久久伊人香网站| 亚洲欧美精品综合一区二区三区| 色哟哟哟哟哟哟| 中文字幕人成人乱码亚洲影| 51午夜福利影视在线观看| 热99re8久久精品国产| 色婷婷久久久亚洲欧美| 一级a爱片免费观看的视频| 国产高清激情床上av| 成人手机av| 多毛熟女@视频| 国产99白浆流出| 宅男免费午夜| 这个男人来自地球电影免费观看| 91九色精品人成在线观看| 国产精品综合久久久久久久免费 | 老鸭窝网址在线观看| 久久人人爽av亚洲精品天堂| 亚洲电影在线观看av| 午夜a级毛片| 国产精品自产拍在线观看55亚洲| 国产国语露脸激情在线看| 亚洲人成伊人成综合网2020| 国产亚洲精品综合一区在线观看 | 丰满人妻熟妇乱又伦精品不卡| 欧美乱码精品一区二区三区| 99热只有精品国产| 欧美丝袜亚洲另类 | 欧美精品啪啪一区二区三区| 精品久久久久久,| 桃红色精品国产亚洲av| 日日夜夜操网爽| 无遮挡黄片免费观看| 黄色视频不卡| 这个男人来自地球电影免费观看| 欧美久久黑人一区二区| 国产成人欧美| 色综合站精品国产| 可以在线观看的亚洲视频| 不卡av一区二区三区| 久久精品aⅴ一区二区三区四区| 亚洲国产精品成人综合色| 窝窝影院91人妻| 99国产极品粉嫩在线观看| 中亚洲国语对白在线视频| 啦啦啦观看免费观看视频高清 | 中亚洲国语对白在线视频| 黄色a级毛片大全视频| 成年版毛片免费区| 最好的美女福利视频网| 桃红色精品国产亚洲av| 国产人伦9x9x在线观看| 国产精品免费视频内射| 日韩欧美一区二区三区在线观看| 日韩高清综合在线| 久久午夜综合久久蜜桃| 亚洲国产高清在线一区二区三 | 国产精品久久久久久人妻精品电影| 老司机福利观看| 国产私拍福利视频在线观看| 亚洲国产精品成人综合色| 国产熟女午夜一区二区三区| 国产精品一区二区免费欧美| 欧美不卡视频在线免费观看 | e午夜精品久久久久久久| 精品欧美一区二区三区在线| 久久人妻av系列| 老司机在亚洲福利影院| 久久狼人影院| 1024视频免费在线观看| 亚洲情色 制服丝袜| 女同久久另类99精品国产91| 99精品欧美一区二区三区四区| 国产国语露脸激情在线看| 中文字幕av电影在线播放| 成人av一区二区三区在线看| 男女床上黄色一级片免费看| 国产欧美日韩综合在线一区二区| 真人做人爱边吃奶动态| 欧美亚洲日本最大视频资源| 琪琪午夜伦伦电影理论片6080| 欧美色视频一区免费| 久久久久久久久免费视频了| 男女下面进入的视频免费午夜 | 久久久久久人人人人人| 亚洲精品粉嫩美女一区| 视频在线观看一区二区三区| 久久久国产成人精品二区| 免费一级毛片在线播放高清视频 | 欧美激情高清一区二区三区| 欧美一级毛片孕妇| 亚洲专区字幕在线| 在线观看免费视频网站a站| av网站免费在线观看视频| 国产麻豆成人av免费视频| 国产成人免费无遮挡视频| 亚洲国产欧美日韩在线播放| 色综合站精品国产| 美女 人体艺术 gogo| 99久久99久久久精品蜜桃| 国产欧美日韩一区二区三区在线| 女生性感内裤真人,穿戴方法视频| 久久午夜亚洲精品久久| 亚洲情色 制服丝袜| 黄色成人免费大全| 久久中文看片网| 91国产中文字幕| 国产成人免费无遮挡视频| 女人高潮潮喷娇喘18禁视频| 日日干狠狠操夜夜爽| 欧美成人免费av一区二区三区| 欧美乱色亚洲激情| 两个人免费观看高清视频| 十八禁人妻一区二区| 欧美久久黑人一区二区| 自线自在国产av| a在线观看视频网站| 国产精品一区二区在线不卡| 久久久久久人人人人人| 国产一区二区三区在线臀色熟女| 国产99久久九九免费精品| 大型黄色视频在线免费观看| 美女高潮喷水抽搐中文字幕| 啦啦啦 在线观看视频| 亚洲精华国产精华精| 免费搜索国产男女视频| 中文字幕久久专区| 欧美av亚洲av综合av国产av| 十八禁人妻一区二区| 国产精品国产高清国产av| 久久中文看片网| 国产精品久久电影中文字幕| 男人舔女人的私密视频| 精品欧美国产一区二区三| 亚洲国产日韩欧美精品在线观看 | 亚洲午夜理论影院| 日韩欧美国产一区二区入口| 女警被强在线播放| av免费在线观看网站| 免费看美女性在线毛片视频| 欧美久久黑人一区二区| 精品国产美女av久久久久小说| 日韩高清综合在线| 最新美女视频免费是黄的| 一级a爱片免费观看的视频| 一级片免费观看大全| av天堂久久9| 男女做爰动态图高潮gif福利片 | 午夜久久久久精精品| 老司机靠b影院| 男女下面插进去视频免费观看| 啦啦啦观看免费观看视频高清 | 婷婷丁香在线五月| 激情视频va一区二区三区| 性色av乱码一区二区三区2| √禁漫天堂资源中文www| 侵犯人妻中文字幕一二三四区| 一夜夜www| 国产成人欧美在线观看| 国产男靠女视频免费网站| 国产精品九九99| 国产成人av激情在线播放| av天堂在线播放| 久9热在线精品视频| 老司机深夜福利视频在线观看| 免费av毛片视频| 成人亚洲精品av一区二区| 动漫黄色视频在线观看| 在线观看午夜福利视频| 亚洲中文日韩欧美视频| 91精品三级在线观看| 色av中文字幕| 国产xxxxx性猛交| 欧美乱妇无乱码| 一级黄色大片毛片| 美女高潮到喷水免费观看| 人妻丰满熟妇av一区二区三区| 午夜福利18| 欧美日韩一级在线毛片| 国产精品亚洲一级av第二区| 嫩草影院精品99| 久久国产亚洲av麻豆专区| 在线永久观看黄色视频| 丰满人妻熟妇乱又伦精品不卡| 99久久久亚洲精品蜜臀av| 丝袜人妻中文字幕| 免费观看精品视频网站| 亚洲中文av在线| 99久久综合精品五月天人人| 老司机靠b影院| 操美女的视频在线观看| 国产精品1区2区在线观看.| 90打野战视频偷拍视频| 国产激情久久老熟女| 黄色 视频免费看| 国产高清有码在线观看视频 | 欧美在线黄色| 亚洲成国产人片在线观看| 亚洲中文字幕日韩| 男女之事视频高清在线观看| 精品国内亚洲2022精品成人| 美女免费视频网站| 色综合欧美亚洲国产小说| 动漫黄色视频在线观看| 最近最新中文字幕大全免费视频| 色综合婷婷激情| 日韩欧美一区视频在线观看| 制服人妻中文乱码| 精品久久久久久,| 成年人黄色毛片网站| 欧美绝顶高潮抽搐喷水| 人人妻人人爽人人添夜夜欢视频| 欧美丝袜亚洲另类 | 中国美女看黄片| 老司机在亚洲福利影院| 久久久久久久午夜电影| 国产精品一区二区在线不卡| 精品久久久久久,| 精品久久蜜臀av无| 一进一出抽搐gif免费好疼| 69av精品久久久久久| 国产1区2区3区精品| 欧美黑人欧美精品刺激| 成人三级做爰电影| 黑人巨大精品欧美一区二区蜜桃| 亚洲人成电影观看| 国产亚洲精品一区二区www| 亚洲性夜色夜夜综合| 国产单亲对白刺激| 久久久久久免费高清国产稀缺| 高清黄色对白视频在线免费看| 中文字幕久久专区| 精品一品国产午夜福利视频| 18禁黄网站禁片午夜丰满| 男人舔女人的私密视频| 91国产中文字幕| 欧美乱色亚洲激情| 19禁男女啪啪无遮挡网站| 99国产精品99久久久久| 久久天堂一区二区三区四区| 亚洲一区高清亚洲精品| 动漫黄色视频在线观看| 欧美乱色亚洲激情| 亚洲第一av免费看| 最新在线观看一区二区三区| 日韩 欧美 亚洲 中文字幕| 国产麻豆成人av免费视频| 人人妻人人澡欧美一区二区 | 国产伦一二天堂av在线观看| 久久久国产精品麻豆| 9色porny在线观看| 变态另类丝袜制服| 久久热在线av| 久久精品影院6| 亚洲第一电影网av| 亚洲男人天堂网一区| √禁漫天堂资源中文www| 国产精品免费一区二区三区在线| 国产精品久久电影中文字幕| 在线永久观看黄色视频| 亚洲avbb在线观看| 亚洲av成人不卡在线观看播放网| 首页视频小说图片口味搜索| 韩国精品一区二区三区| 中出人妻视频一区二区| 无遮挡黄片免费观看| 精品午夜福利视频在线观看一区| 国产野战对白在线观看| 一进一出抽搐动态| 国产xxxxx性猛交| 两人在一起打扑克的视频| 国产精品久久久av美女十八| 日本撒尿小便嘘嘘汇集6| 久久精品91蜜桃| 国产熟女午夜一区二区三区| 午夜两性在线视频| 91国产中文字幕| 久久国产精品影院| 两个人视频免费观看高清| 精品福利观看| 久久久久久久精品吃奶| 免费在线观看视频国产中文字幕亚洲| av有码第一页| 亚洲专区字幕在线| 亚洲人成77777在线视频| 国产成人av激情在线播放| 亚洲精品在线观看二区| 成人亚洲精品av一区二区| 欧美在线黄色| 最新在线观看一区二区三区| 波多野结衣高清无吗| 可以在线观看的亚洲视频| 在线观看66精品国产| 国产熟女午夜一区二区三区| 日韩中文字幕欧美一区二区| 色播亚洲综合网| 精品国产国语对白av| 中文字幕另类日韩欧美亚洲嫩草| 看片在线看免费视频| 99国产精品免费福利视频| 欧洲精品卡2卡3卡4卡5卡区| 天天躁狠狠躁夜夜躁狠狠躁| 久久伊人香网站| 亚洲国产毛片av蜜桃av| 久久香蕉激情| 激情视频va一区二区三区| 国产麻豆69| 色哟哟哟哟哟哟| 母亲3免费完整高清在线观看| 亚洲 欧美一区二区三区| 十八禁网站免费在线| 婷婷丁香在线五月| 嫩草影视91久久| 18禁美女被吸乳视频| 久久精品国产99精品国产亚洲性色 | 黄色a级毛片大全视频| 天天躁夜夜躁狠狠躁躁| 制服丝袜大香蕉在线| 女人被狂操c到高潮| 曰老女人黄片| 午夜福利,免费看| 亚洲一卡2卡3卡4卡5卡精品中文| 韩国av一区二区三区四区| 日韩欧美国产一区二区入口| 搡老妇女老女人老熟妇| 亚洲欧美精品综合久久99| 9热在线视频观看99| 一级a爱片免费观看的视频| 成年人黄色毛片网站| 精品国产国语对白av| 国产私拍福利视频在线观看| 正在播放国产对白刺激| 久久狼人影院| 大码成人一级视频| 一区二区三区国产精品乱码| 正在播放国产对白刺激| 身体一侧抽搐| 免费高清在线观看日韩| 亚洲欧美激情综合另类| 一级毛片高清免费大全| 午夜福利18| 精品欧美一区二区三区在线| 中文字幕人成人乱码亚洲影| 亚洲第一欧美日韩一区二区三区| 美女大奶头视频| a级毛片在线看网站| 亚洲一区二区三区不卡视频| 嫩草影视91久久| 久久久水蜜桃国产精品网| 国产麻豆成人av免费视频| 欧美性长视频在线观看| 国产精品,欧美在线| 真人一进一出gif抽搐免费| 91在线观看av| 婷婷六月久久综合丁香| 久久久久国内视频| 欧美最黄视频在线播放免费| 亚洲精品在线观看二区| 女性生殖器流出的白浆| 精品午夜福利视频在线观看一区| 制服诱惑二区| 亚洲天堂国产精品一区在线| 欧美日本亚洲视频在线播放| 国产高清videossex| av欧美777| 老司机福利观看| av中文乱码字幕在线| 18禁黄网站禁片午夜丰满| 麻豆久久精品国产亚洲av| 很黄的视频免费| 久久欧美精品欧美久久欧美| 午夜精品久久久久久毛片777| 999久久久精品免费观看国产| 一区二区三区精品91| 亚洲专区国产一区二区| 给我免费播放毛片高清在线观看| 免费在线观看视频国产中文字幕亚洲| 国产精品九九99| 国产精品一区二区免费欧美| 97人妻精品一区二区三区麻豆 | 在线观看免费视频网站a站| 在线av久久热| 男女午夜视频在线观看| 色尼玛亚洲综合影院| 国产精品久久久久久精品电影 | 操美女的视频在线观看| 国产一卡二卡三卡精品| 日韩欧美国产在线观看| 色综合亚洲欧美另类图片| 免费久久久久久久精品成人欧美视频| 成人免费观看视频高清| netflix在线观看网站| 一个人免费在线观看的高清视频| 波多野结衣巨乳人妻| 麻豆av在线久日| 国产精品免费视频内射| 免费在线观看完整版高清| 日韩一卡2卡3卡4卡2021年| 国产精品电影一区二区三区| 精品国产亚洲在线| 91字幕亚洲| 久久草成人影院| 老熟妇仑乱视频hdxx| 中亚洲国语对白在线视频| 国产熟女xx| 亚洲国产精品成人综合色| 亚洲国产欧美网| 欧美激情极品国产一区二区三区| 美国免费a级毛片| 久久中文字幕人妻熟女| 91在线观看av| 亚洲国产精品成人综合色| 激情视频va一区二区三区| 18美女黄网站色大片免费观看| 亚洲自偷自拍图片 自拍| 亚洲av成人av| 91老司机精品| 久热这里只有精品99| 欧美一级a爱片免费观看看 | 天天躁夜夜躁狠狠躁躁| 中文字幕人妻熟女乱码| 国产成人系列免费观看| 一区在线观看完整版| 又黄又爽又免费观看的视频| 欧美激情高清一区二区三区| 91在线观看av| 亚洲熟妇熟女久久| 中出人妻视频一区二区| 亚洲美女黄片视频| 日本撒尿小便嘘嘘汇集6| 国产成人欧美| 国产成人精品久久二区二区91| 一级毛片精品| 在线视频色国产色| 99久久精品国产亚洲精品| 伊人久久大香线蕉亚洲五| 亚洲七黄色美女视频|