• <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 ?

    Numerical analysis of rockfall and slope stability along the Karakorum Highway in Jijal-Pattan

    2021-03-06 02:45:20,,3,4,,,,,

    , ,3,4, , , , ,

    1a.Key Laboratory of Mountain Hazards and Earth Surface Process; 1b.Institute of Mountain Hazards and Environment, Chinese Academy of Sciences (CAS), Chengdu 610041, P.R. China;2. University of Chinese Academy of Sciences, Beijing 100049, P. R. China; 3. CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, P. R. China; 4. China-Pakistan joint Research Center on Earth Sciences, Islamabad, Pakistan)

    Abstract: Along the Karakorum Highway (KKH), the key route for the China-Pakistan Economic Corridor, there are many rockfalls and unstable slopes, usually caused by tectonic movement and rainfall on the fractured rocks and slopes. This paper presents a numerical investigation of the rockfall and slope stability along the Karakorum Highway in Jijal-Pattan, Northern Pakistan using DIPS, GeoRock 2D and SLIDE, focusing on rockfall and slope stability along the KKH to develop countermeasures. Along the KKH, two major sections susceptible to rockfalls were selected to investigate the mechanism of rockfall and slope instability. The stereographic projection analysis following four sets of joints indicates that both sections are prone to plane failure and wedge failure. Based on the limit equilibrium theory, under static loading, the slope for Section 1 showed a stability coefficient of 0.917, representing its instability, and the slope in Section 2 has a stability coefficient of 1.131 depicting its slight stability. However, under the seismic condition, the stability coefficients of the slopes were lower than 1 for both sections, which indicates their instability. The results by GeoRock 2D reveal that in Section 1 the fallen rock mass attained the bounce height of 33 m, and in Section 2 it attained a bounce height of 29 m. The fallen rocks in Section 1 have the total kinetic energy of 1 135.099 kJ with a velocity ranging from 0.5 m/s to 44 m/s, while in Section 2 the fallen rocks have a velocity ranging from 0.5 m/s to 40.901 m/s with a damage capacity of 973.012 kJ. This study showed the rockfalls and landslides along the KKH have great damage potential.

    Keywords:Karakorum Highway; steep rock slope; stereographic projection; slope stability analysis; dynamic process

    1 Introduction

    Rockfalls and landslides are widely known hazards in mountainous areas. Rockfalls usually include the quick movement of rock boulders in the form of falling, bouncing, or rolling[1]and are a great threat to people, their livelihoods, environmental services and resources, infrastructure, and economic, social and cultural assets[2]. One of the major causes of rock slope failure is the construction of roads without proper geological and geotechnical engineering investigation of the natural rock slopes[3-5]. In addition, it is not possible to continuously monitor the rock slope, particularly in the rainfall season. The threat of rockfall exists whenever humans or nature disturb the natural balance of the rock slope[6-8].

    The forces triggering rockfalls are usually earthquakes, temperature fluctuation, and neotectonic activity[9-12]. The study of rockfalls along highways is of interest to many researchers. Singh et al.[5]investigated rockfall activity along the Luhri hydro-electric project on the Sutlej River in Himachal Pradesh, India, and performed a kinematic analysis to assess the failure mode. RocFall v4.0 was used to study the trajectories and energy dissipation of the falling rock. It was observed that the main reasons for the rockfall were weak rock mass and rainfall. They described that the fall of rock blocks was a potential threat to human lives and infrastructure. Singh et al.[4]also analyzed the stability of the road cut cliff face along SH-121, in Maharashtra, India through rockfall analysis and finite element modelling. They reported that the study area was prone to rockfall hazards, particularly in rainfall events, due to the steep and highly jointed slopes along the roads.

    Slope failure is another great threat along the KKH. Slope failure is the result of forces such as increased destabilization or seismic events, external load, undermining, increased water pressure in rock cracks, hairline cracks and frost wedging, mining and loss of capillary pressure[13]. Slope stability analysis can be carried out using the limit equilibrium method, numerical modelling techniques and kinematic analysis. Kinematic analysis is suitable for identifying slope failure types using discontinuities and joint orientations[14-16]. Slope stability issues can be minimized with in-depth monitoring and analysis[17]. Akram et al.[18]carried out the stability evaluation of a slope in Balakot, Pakistan, which is one of the seismically active regions in Pakistan. These researchers performed kinematic analysis using limit equilibrium methods to assess the failure modes of slopes and to evaluate the stability of slopes under different conditions. It was concluded that the slope failure modes were plane, wedge, and toppling, with less likely chances of circular failures. The above-mentioned studies were focused mainly on the assessment of rockfall due to slope orientation, rock joint condition, and dynamic stability. However, in the Jijal-Pattan area, the rockfall results from earthquakes along with weak rock conditions, steep slopes, and the lack of geotechnical engineering investigations. The rockfall assessment in such areas should be carried out by performing slope stability analysis in both static and dynamic conditions along with kinematic analysis to assess the failure modes of the rockfalls.

    The northern part of Pakistan is comprised of high mountain ranges with a history of rockfalls due to seismic activity, particularly in the area between Jijal and Pattan[19]. The only mode of transportation in such a mountainous area is by road, but recurring rockfalls and landslides lead to damage to the infrastructure, residents, and travelers. The Jijal-Pattan road is an important part of the China-Pakistan Economic Corridor (CPEC). However, due to complex tectonic conditions and multiple seismic events, this section of the road is characterized by highly fractured and jointed rocks. Further, ill-considered rock cuts for infrastructure development in this area facilitate rockfalls and landslides. Nonetheless, there has been little study of the rockfalls and landslides in this area, and it is crucial to investigate the mechanism of the rockfalls and landslides here due to the threat to human life and infrastructure.

    This research aims to reveal the stability of the slope and the extent of the threat from rockfalls and landslides along the road from Jijal to Pattan through field investigation and numerical studies. Along and across the slopes, DIPS was initially used to obtain the geological orientation and perform kinematic analysis of the major planes[20]. GeoRock 2D software was used to display the rockfall analysis based on the kinematic analysis[21]. The software SLIDE 6.0 was used for the numerical slope stability analysis[22]. The key contribution of this study is the usage of three different models to assess the slope stability and rockfall risk in the Jijal-Pattan area to fill the research gap.

    2 Geo-location of the research area

    Northern Pakistan is linked to Western China through the Karakorum Highway (KKH), which forms a part of the China-Pakistan Economic Corridor (CPEC). The rising of the Himalayan, Karakorum, and Hindu Kush Mountains represent the collision of the Indian and the Eurasian plates and the Kohistan Island Arc[23]. The study area is the Lower Kohistan District (Jijal-Pattan) along the Karakorum Highway in the Khyber Pakhtunkhwa Province, Pakistan. The Lower Kohistan District extends from latitude 34°54′ to latitude 35°52′ north and from longitude 72°43′ to longitude 73°57′ east. It borders the Ghizer and Diamer districts on the north and northeast, the Manshera District on the south-east, the Battragram District on the south, and the Shangla and Swat districts on the west. The geology of the study area mainly contains sedimentary rocks, igneous rocks, and metamorphic rocks. Along the KKH, highly active rockfall areas have been identified. The lithology of the study area consists of the Besham group, the Jijal Complex, the Kamila amphibolite, and the Chilas Complex.

    From Pattan to Kamila and north along the Indus River, the Kamila amphibolites are well exposed. South and north of Kamila lie large gneissic and huge granitic bodies consisting of sheet-like intrusions. During the field visit it was observed that the section is dominated by amphibolies of the Besham group, which is of Cretaceous age intruded by younger granodioritic gneiss with little schists at the top of the slope.

    The northern part of Jijal along the KKH lies in a highly vulnerable zone. It consists of the highly fragmented Jijal Complex ultra-mafic rocks. It is extremely jointed and locally sheared because the study area is located in the hanging wall of the Main Mantle Thrust (MMT)[19].

    This seismic area is only 3 km away from the site of the earthquake in Pattan (Magnitude=6.2, Depth=22 km) on 28 December 1974[24]. In this part, the topography is steep, mostly with slope angles of more than 50°, even up to 90°. The area is located in the monsoon region, where the annual average precipitation is over 400 mm[25]. A large number of rockfalls have occurred due to heavy rainfall and biological weathering, blocking the roads for weeks. The surface of the slope is moderately weathered, which has produced clay with medium vegetation cover. Due to the dominant weathering, the slope surface is covered by rock fragments ranging in size from pebbles to boulders. Fault closeness, biological weathering, strong seismicity, fractured rock mass, heavy rainfall, and steep topography, are all responsible for the rockfalls in this region.

    Geological Cross-Section of the slopes: Section 1 is located along the Karakorum highway between the Pattan Tehsil and the Mali Dhera Kohistan District. During the field survey, it was observed that the section is dominated by amphibolites of the Besham group. Cretaceous age intruded by younger granodioritic gneiss with little schists at the top of the slope were also observed. The section is moderately jointed with an almost 100 m-high slope facing N30E and a dip angle ranging from 67° to 80°. The Cretaceous amphibolite sheet intrusion sub-parallel to the fabric and banding is very common throughout the Besham group. Most parts of the slope were covered by fallen rocks, indicating the high risk of rockfall impacting the asphalt road. The geological cross-section of both sections is given in Fig.1. Section 2 is situated a few kilometers away from Dubair, Kohistan. Cretaceous amphibolite dominates in this highly fractured section and a well-defined joint system was observed in this section. The slope face dips in the N58E direction with an average dip angle of 70°. The surface of the slope is moderately weathered, producing clay that favors medium vegetation cover. Due to the dominant weathering, the slope surface is covered by rock fragments ranging in size from pebbles to boulders.

    Fig.1 Geological cross section of (a) Section 1 and (b)Section 2

    These amphibolites are coarse-grained with a fracture filling of quartz. The overall dip and strike of the granodioritic gneiss are 60° and N82E, respectively. A geological cross-section is given in Fig.1.

    3 Material and methods

    The design of the cliff is an iterative process, and no principles are defined throughout all areas[26], therefore, every survey is important. The rockfall prone areas were identified during a field survey. The slope height, slope angle, block size, block shape, joint spacing and biological weathering of each section were identified and measured during the field study. The open joints, blocks overhanging the KKH and biological weathering were found to be vulnerable to instability. However, only a few man-made cut slopes are located along the KKH. The Rocscience software SLIDE 6.0 and DIPS were used to analyze the profile of each section, GeoRock 2D software based on kinematic analysis was used to display the orientation of major planes along and across the slope to investigate the slope failure. In this study, two different vulnerable sites were chosen and analyzed kinematically for rockfall by numerical analysis, which are explained below.

    The slope may be naturally formed or man-made.The man-made slope includes excavation/cut for construction, borders of embankments, dams, canals etc. Many factors contribute to slope failure, including 1) forces due to the seepage of water, 2) gravitational forces, 3) sudden lowering of the water table adjacent to the slope, 4) earthquake forces, 5) reduction in strength of the material and 6) a non-engineered cut. Slope failure occurs in several modes. Cruden and Varnes[27]classified slope failure into five major categories: fall, slide, topple, spread, and flow.

    Different methods are available to compute the slope stability for rock and soil. Due to the advancement of computer technology, a number of slope stability tools exist for both rock and mixed rock-soil slopes[28].

    Kinematic analysis shows the orientation of rock discontinuities (joints, fault, bedding, etc.) is the leading factor influencing the stability of rock slopes[26]. Different failure modes are associated with the orientation of discontinuities for plane failure, wedge failure, toppling failure and circular failure[5-6,29-30]. Kinematic analysis using stereographic projection gives the geometry of discontinuities and analyzes the result to predict the type of failure. Scanline survey was used in this study to find the parameters of the rock discontinuities for stereographic analysis. These parameters include the type of discontinuities, persistence, aperture, property of infilling, spacing, roughness, water condition and lithology.

    A rockfall is the movement of a rock or boulder sliding, toppling or falling along a steep or sub-vertical slope, which proceeds down a steep hill both bouncing and flying or rolls downwards over debris slopes or talus[1]. Various geometrical, geological, geotechnical and climatic influences lead to the initiation of significant rockfall incidents in mountainous regions. In this study, the widely used GeoRock 2D software was used to display the orientation of major planes along and across the slope to analyze the slope failure.

    The most commonly used factors of the environmental condition of the study area[21, 31-32]are shown in Table 1.

    Table 1 Boulder properties of Section 1 and Section 2

    The minimum and maximum mass of a rock boulder in Section 1 is 12 kg and 4 486 kg, respectively, while the minimum and maximum mass of a rock boulder in Section 2 is 9.8 kg and 5 972 kg, respectively, as shown in Table 1. Section 1 is a highly weathered rockmass jointed with some large spacing and size blocks in the face zone, while Section 2 is highly fractured with a thin cover of weathered overburden. The rockfall simulation technique calculated the trajectory, kinetic energy, velocity motion, bounce height and run-out distance of the falling blocks based on the theory of collision and laws of motion[33].

    The numerical analysis of Section 1 and Section 2 was carried out using the commercial software Rocscience SLIDE 6.0. Since the strength of the rock mass is controlled by discontinuities, the Hoek-Brown failure criterion is used in the analysis. The safety factor was calculated based on the limit equilibrium method (LEM). The limit equilibrium method is commonly used in geotechnical engineering problems related to seepage and the stability of slopes. It uses the perfectly plastic Mohr-Coulomb criterion to model soil stress-strain behavior.

    4 Results

    4.1 Kinematic slope stability analysis

    Based on stereographic analysis, four sets of joints were observed. The types of critical discontinuity planes that are prone to fail are listed in Table 2. The planar sliding analysis results for Section 1 show that only 3/7 poles are in the critical zone, having 42.86% probability of plane failure. When considering the individual sets, 2/3 poles are in the critical zone in set 1 with 66.67% probability of plane failure. For set 2, 1 pole has a 100% probability of failure (Fig.2(a)). For Section 2, out of 6 poles, only 2 poles are in the critical planar sliding zone, with 33.33% probability of plane failure. However, for set 2, all the poles are in the critical state having 100% probability of plane failure (Fig.2(d)). The results revealed that set 2 in both sections is more susceptible to planar failure (Table 2). Nagendran et al.[34]mentioned in their research, the overall plane failure was 8.66%, where the probability of failure was 15.40% (set 1), which is in line with our results. Section 1 wedge sliding analysis presents that 11/15 inter-sections are under the critical condition, with 73.33% probability of failure. For Section 2, the critical inter-sections are 10/15, with 66.67% probability of failure (Fig.2(b) and (d)), which is comparable to the results of Tiwari et al.[35]and Sazid et al.[36]. This indicates that the percentage of critical intersections in these analyzed sections is very high and more prone to wedge failure (Table 2).

    Table 2 Dominant joint set data at two rockfall sites

    4.2 Rockfall slope stability analysis

    Ritchie[37]proposed that falling blocks achieve numerous types of motion, depending on the slope structure and the mechanical properties of the blocks. In free fall movement, there is hardly any interaction with the slope surface, while the falling mass continually interacts with the surface in other motions such as rolling, sliding and bouncing and each impact changes their impact and energy.

    Fig. 2 Plane failure and wedge failure of

    Impact positions of the falling rock bodies (X(m) andY(m)), the falling rock mass (kg), first strike point and run-out distance of falling rocks in both sections are described. The slope height is 103.87 m in Section 1 while in Section 2 it is 123 m as shown in Fig.3, which causes the blocks to achieve greater velocity and even extensive momentum. In all situations, rock movement starts with sliding. The falling rocks strike the rock slopes and bounce and roll several times before stopping or resting at the asphalt. The estimated maximum bounce heights for both sections plotted with the run out distance, are shown in Fig.4(c) and (d).

    Fig.3 Slope face, trajectory, motion and run out the distance of the falling body at (a) Section 1 and (b) Section 2

    The results showed that the rock mass in Section 1 attained a maximum bounce height of 33 m, while in Section 2, it attained a maximum bounce height of 23 m. The damage capacity of the rockfall based on the translational velocity and kinetic energy values obtained through rockfall analysis, shows that the damaging impact of the rockfall is as high as 1 135.099 kJ with a falling velocity ranging from a minimum of 0.5 m/s to a maximum of 44 m/s in Section 1, as given in Fig.4(a), (e) and Table 3.

    The values of the damage capacity of the fallen rock mass in Section 2 are estimated to be 973.012 kJ, with a maximum velocity of 40.901 m/s and a minimum velocity of 0.5 m/s, as shown in Fig.4(b), (f) and Table 3. The parabola height, kinetic energy and velocity of falling rocks are greatly influenced by slope height, slope angle and the

    Table 3 Statistic computations of Section 1 and 2

    Fig.4 Energies at each strike of the fallen rock mass (a)(b),the trajectories and their parabolic heights attained by the fallen rock bodies(c)(d),and velocity pattern of the fallen rock bodies(e)(f) at Section 1 and Section 2.

    weight of the falling boulders. Similar results were obtained by Choi et al.[31]. Perret et al.[38]divided kinetic energy into three intensity groups to determine the hazardous zones. The highest intensity zone had a kinetic energy of more than 300 kJ, which is achieved in this study in both sections, as shown in Table 3. The medium intensity zone has a kinetic energy of 30~300 kJ and the low- intensity zone has a kinetic energy of <30 kJ. Dorren[12], Perret et al.[38]and Basson[39]suggested that a descending block reaches a velocity of 5~30 m/s and eventually it stops underneath a slope of 30°.

    These analyses showed that the majority of the fallen rocks stopped at the roadside after losing most of their energy, with few falling further down to the valley floor. So the chance of impacting the commuters on a mountain road is very high.

    4.3 Numerical analysis

    Limit equilibrium method (LEM) parameters including cohesion, angle of friction, unconfined compressive strength (UCS), unit weight, the Geological Strength Index (GSI) value and loading type were used for the purpose of calculation, as shown in Table 4. Considering the seismic loading of 0.24g, Seismic Zone 2B[40]parameters were followed. These analyses followed Janbu methodology, and 638 possible slope slice surfaces were considered. For Section 1, 25 sets of different critical parameter slices were calculated such as base cohesion, base friction angle, shear stress, and shear strength, with the numeric model shown in Fig.5 (a) and (c). For Section 2, 550 slices were considered for the calculation of these parameters, and 19 slice sets were defined. Graphical representation of Section 2 under static and dynamic conditions, is shown in Fig.5 (b) and (d). These analyses show that the stability of the slope is directly dependent on the safety factor, which is 0.917 for Section 1, showing that it is unstable in static conditions, while the safety factor for Section 2 is 1.131, showing that it is slightly stable under static conditions (Table 5, Fig.5 (a) and (b)), whereas the safety factor is defined from the numerical analysis under dynamic conditions for Section 1 and Section 2, which is 0.539 and 0.784, respectively (Table 5, Fig.5 (c) and (d)). Exposure to any seismic activity, whether by artificial blasting or natural, such as an earthquake, can induce movement down the slope under gravity and both the slopes can fail at any time producing socio-economic disaster in the area. A similar trend of static condition to the dynamic condition was acquired by Akram et al.[18]

    Table 4 Average values of the parameters

    Note:UCS is unconfined compressive strength; GSI is Geological Strength Index;sandaare constant values which depend upon the characteristics of the rock mass; mb is a reduced value (for the rock mass) of the material.

    Table 5 Derived parameters obtained from the lab analysis

    Fig.5 Numerical slope stability model without seismic loading of (a) Section 1 and (b) Section 2 and 13-5.tifwith seismic loading of (c) Section 1 and (d) Section 2

    5 Discussion

    At each site, hundreds of dip/dip directions were calculated by Brunton compass while dominant joint set data were measured by pole density. In a major part, four sets of slightly weathered joints were identified at each site at diverse persistence and frequency, as listed in Table 2. The results of the kinematic studies are used in this study to evaluate the failure mode in both sections. Rocscience Software DIPS was used to display the major planes along and across the slope and to analyze the data for failure types, as shown in Fig.2.

    Rockfall slope stability analysis shows that the blocks were triggered to fall due to the steep rock slope face, reaching the road and causing undesirable consequences. The trajectories of their fall and their endpoints for Section 1 and 2 are shown in Fig.3. Most of the rock boulders reached the bottom of the slope due to the absence of benches. Their trajectories are decided by the collision of the rock boulder on the face of the slope.

    Additionally, the orientation of the blocks is determined by the properties of the slope. Upon the first impact, a large amount of energy is lost and the blocks are separated into smaller sections. Most of them may stop at their first impact, and some may move hundreds of meters downhill to the valley floor.

    Numerical slope stability analysis analyzes the equilibrium between driving forces and resisting forces and takes into account material parameters like cohesion, angle of friction, USC, unit weight and GSI value, as shown in Table 4. Limit equilibrium analysis is used for numerical slope stability analysis to define the critical surface on which the movement of rock or soil occurs or is expected to occur. The critical surface is based on the minimum factor of safety. The limit equilibrium method (LEM) is based on a common approach "resisting forces/driving forces"[28].

    Based on the analysis of rockfall events,the failure characteristics of the slopes, and the energy of the falling blocks, appropriate structural countermeasures are proposed to improve the stability of the selected sections with the aim of avoiding geological hazard. The suggested structural countermeasure is an anchored rock mesh system with rock bolts as additional support. The anchored rock mesh system consists of a steel mesh anchored by bolts, which covers the rock surface and restrains the movement of small rock blocks on the slope. Additionally, the selected sections are also susceptible to slope failure; therefore, rock bolting is recommended to increase the safety factor to prevent the sliding of the slope.

    6 Conclusion

    The Karakorum Highway in Pakistan is not only a very important route for the business trade between China and Pakistan, but also important for domestic trading. The area along the Karakorum highway is very vulnerable to slope failure and rockfalls that could put people at risk and result in significant finacial losses. The kinematic analysis showed that the two study sites are highly jointed with a dip/dip direction of 67/32, indicating 100% susceptibility to sliding under gravity. Rockfall analysis showed that the fallen rock mass in section 1 has attained a maximum bounce height of 33 m whereas the fallen rock in in section 2 has attained a maximum bounce height of 23 m. The damage capacity of the fallen rock in section 1 was probably 1135.099 kJ, with the velocity varying from 0.5 m/s to 44 m/s, while in section 2, it was 973.012 kJ, with a minimum velocity of 0.5 m/s and a maximum velocity of 40.901 m/s. These analyses also showed that the majority of the fallen rocks stopped at the road, having lost most of their energy, with few falling further down to the valley floor. Therefore, the chance of falling rocks impacting commuters is high. Based on the numerical analysis, the stability of the slope directly depends on the safety factor, which was 0.917 for section 1, showing that it is unstable in the static condition, while the safety factor of section 2 was 1.131, showing that it is slightly stable under the static condition. However, the safety factors for both sections were less than 1 under the dynamic condition, which means that the slopes are unstable and can slide any time. To avoid the hazards of rockfall and landslides, engineering countermeasures are proposed.

    Acknowledgements

    The authors would like to acknowledge the financial support from The Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA20030301) and "Belt & Road" international cooperation team for the "Light of West" program of CAS.

    国产精品亚洲av一区麻豆| 精品久久久久久久人妻蜜臀av| 欧美日韩瑟瑟在线播放| 国产精品自产拍在线观看55亚洲| 欧美在线黄色| 91字幕亚洲| 精品一区二区三区视频在线观看免费| 搞女人的毛片| 国产综合懂色| 久久国产乱子伦精品免费另类| 精品一区二区三区av网在线观看| 久久久国产成人精品二区| 夜夜夜夜夜久久久久| 亚洲国产色片| 国产精品 国内视频| 偷拍熟女少妇极品色| 国产伦精品一区二区三区视频9 | 国产真实乱freesex| 好男人在线观看高清免费视频| 国产私拍福利视频在线观看| 欧美+亚洲+日韩+国产| 亚洲成人免费电影在线观看| 在线观看免费视频日本深夜| 亚洲av五月六月丁香网| 熟妇人妻久久中文字幕3abv| 午夜福利18| 国产精品九九99| 日本一二三区视频观看| 99热这里只有是精品50| 精品一区二区三区视频在线观看免费| 亚洲熟妇中文字幕五十中出| 午夜精品在线福利| 人妻丰满熟妇av一区二区三区| 亚洲专区国产一区二区| 91麻豆精品激情在线观看国产| 99国产综合亚洲精品| 亚洲国产色片| 亚洲国产欧美网| ponron亚洲| 国产成年人精品一区二区| а√天堂www在线а√下载| 日本撒尿小便嘘嘘汇集6| 一级毛片精品| 97碰自拍视频| 国内毛片毛片毛片毛片毛片| 少妇的丰满在线观看| 在线国产一区二区在线| 男女午夜视频在线观看| 最近最新中文字幕大全免费视频| 日本三级黄在线观看| 欧美不卡视频在线免费观看| 他把我摸到了高潮在线观看| 香蕉国产在线看| 久久午夜综合久久蜜桃| 12—13女人毛片做爰片一| 天堂动漫精品| 午夜激情福利司机影院| 国产伦在线观看视频一区| 嫩草影视91久久| 亚洲中文av在线| 一级作爱视频免费观看| 好看av亚洲va欧美ⅴa在| 午夜福利在线在线| 51午夜福利影视在线观看| 女人被狂操c到高潮| 国产亚洲精品一区二区www| 欧美+亚洲+日韩+国产| 欧美性猛交黑人性爽| 国产精品美女特级片免费视频播放器 | 亚洲国产日韩欧美精品在线观看 | 久久久久久大精品| www国产在线视频色| 无限看片的www在线观看| 日本与韩国留学比较| 天天添夜夜摸| 成人亚洲精品av一区二区| 日韩国内少妇激情av| 日韩成人在线观看一区二区三区| 欧美在线一区亚洲| 国产又黄又爽又无遮挡在线| 特级一级黄色大片| 黄色 视频免费看| 午夜激情欧美在线| 又大又爽又粗| 一夜夜www| 香蕉丝袜av| 欧美性猛交╳xxx乱大交人| 变态另类丝袜制服| 国产一区二区三区在线臀色熟女| 亚洲精品中文字幕一二三四区| www.www免费av| 成人性生交大片免费视频hd| 欧美av亚洲av综合av国产av| 偷拍熟女少妇极品色| aaaaa片日本免费| 国产熟女xx| 亚洲自拍偷在线| 亚洲中文av在线| 国内精品久久久久久久电影| 欧美精品啪啪一区二区三区| 午夜免费观看网址| 亚洲人与动物交配视频| 亚洲欧美日韩东京热| 精华霜和精华液先用哪个| 69av精品久久久久久| 亚洲精品456在线播放app | a级毛片a级免费在线| 免费在线观看成人毛片| 色老头精品视频在线观看| 亚洲片人在线观看| 亚洲色图 男人天堂 中文字幕| 国产 一区 欧美 日韩| 亚洲电影在线观看av| 波多野结衣高清作品| 在线观看日韩欧美| 又黄又粗又硬又大视频| 亚洲激情在线av| 欧美乱妇无乱码| 成人一区二区视频在线观看| 亚洲自拍偷在线| 亚洲aⅴ乱码一区二区在线播放| 亚洲国产精品久久男人天堂| 每晚都被弄得嗷嗷叫到高潮| 男女之事视频高清在线观看| 两个人看的免费小视频| 国内精品美女久久久久久| 国产三级黄色录像| 国产v大片淫在线免费观看| 国内精品一区二区在线观看| 亚洲av免费在线观看| 成人性生交大片免费视频hd| 亚洲va日本ⅴa欧美va伊人久久| 色噜噜av男人的天堂激情| 麻豆av在线久日| 中文字幕久久专区| 婷婷精品国产亚洲av在线| 搡老妇女老女人老熟妇| 午夜久久久久精精品| 亚洲一区二区三区色噜噜| 女生性感内裤真人,穿戴方法视频| 免费在线观看成人毛片| 久久国产精品影院| 90打野战视频偷拍视频| 蜜桃久久精品国产亚洲av| 国产亚洲精品久久久久久毛片| 亚洲国产欧洲综合997久久,| 久久草成人影院| 亚洲专区国产一区二区| a级毛片a级免费在线| 99久国产av精品| 小说图片视频综合网站| 国产精品爽爽va在线观看网站| 国产单亲对白刺激| 999精品在线视频| 久久香蕉国产精品| www.精华液| 精品国产超薄肉色丝袜足j| 久久精品综合一区二区三区| 精品99又大又爽又粗少妇毛片 | 美女 人体艺术 gogo| 欧美乱码精品一区二区三区| 国产私拍福利视频在线观看| 色视频www国产| 网址你懂的国产日韩在线| 欧美黄色片欧美黄色片| 久久久国产成人精品二区| 在线观看66精品国产| 九色成人免费人妻av| 老司机午夜十八禁免费视频| 国产精品1区2区在线观看.| 日本精品一区二区三区蜜桃| 免费观看的影片在线观看| 久久久久精品国产欧美久久久| 在线观看66精品国产| 久久久国产欧美日韩av| 久久久久九九精品影院| 搞女人的毛片| 变态另类丝袜制服| svipshipincom国产片| 亚洲一区二区三区色噜噜| 极品教师在线免费播放| 久久热在线av| 国产成人系列免费观看| 别揉我奶头~嗯~啊~动态视频| 国产免费男女视频| 天堂√8在线中文| 国内精品久久久久久久电影| 中文资源天堂在线| 国产男靠女视频免费网站| 亚洲熟妇熟女久久| 亚洲人成电影免费在线| 国产综合懂色| 欧美乱码精品一区二区三区| 91字幕亚洲| 国产成人福利小说| 亚洲成av人片免费观看| 一本精品99久久精品77| 黄色日韩在线| 久久精品aⅴ一区二区三区四区| 亚洲av熟女| 99久久综合精品五月天人人| 国产精品99久久久久久久久| 午夜福利18| 极品教师在线免费播放| 国产69精品久久久久777片 | 亚洲性夜色夜夜综合| 欧美黄色淫秽网站| 一区二区三区激情视频| 欧美激情在线99| 亚洲 欧美一区二区三区| 中文字幕人成人乱码亚洲影| 午夜激情欧美在线| av福利片在线观看| 日本免费a在线| 精品久久久久久久久久免费视频| 久久这里只有精品中国| 亚洲欧美日韩高清专用| 国产探花在线观看一区二区| 国产黄片美女视频| 日本五十路高清| 日日干狠狠操夜夜爽| 精品久久久久久久久久免费视频| 国产高清激情床上av| 日韩有码中文字幕| 精品国产超薄肉色丝袜足j| 性色av乱码一区二区三区2| 久久久精品大字幕| 国产免费av片在线观看野外av| 18禁黄网站禁片午夜丰满| 国产精品一区二区三区四区免费观看 | 香蕉丝袜av| 久99久视频精品免费| 精品国内亚洲2022精品成人| 国产一级毛片七仙女欲春2| 国产不卡一卡二| 精品免费久久久久久久清纯| 高清毛片免费观看视频网站| 国产精品久久电影中文字幕| 国产精品国产高清国产av| 国产又色又爽无遮挡免费看| 久久久久久久精品吃奶| 欧美日韩亚洲国产一区二区在线观看| 曰老女人黄片| 99国产综合亚洲精品| 午夜久久久久精精品| 精品电影一区二区在线| 性色av乱码一区二区三区2| 欧美最黄视频在线播放免费| 色综合亚洲欧美另类图片| 美女高潮的动态| 国产一级毛片七仙女欲春2| 亚洲av熟女| 看片在线看免费视频| 国产精品久久久久久精品电影| 很黄的视频免费| 全区人妻精品视频| 亚洲五月天丁香| 国产伦在线观看视频一区| АⅤ资源中文在线天堂| 黄色丝袜av网址大全| 午夜福利18| 在线观看日韩欧美| 国产精品亚洲一级av第二区| 老鸭窝网址在线观看| 国产亚洲精品综合一区在线观看| 变态另类丝袜制服| 99热这里只有是精品50| 99久久精品热视频| 女人被狂操c到高潮| 国产高清视频在线播放一区| 一本一本综合久久| 一区二区三区激情视频| 这个男人来自地球电影免费观看| 国产精品国产高清国产av| 亚洲狠狠婷婷综合久久图片| 波多野结衣巨乳人妻| 九九久久精品国产亚洲av麻豆 | 国产一级毛片七仙女欲春2| 99国产精品一区二区蜜桃av| 老司机深夜福利视频在线观看| 久久香蕉国产精品| 99精品在免费线老司机午夜| 男女床上黄色一级片免费看| 国产 一区 欧美 日韩| 一a级毛片在线观看| 国产视频内射| 午夜福利在线在线| 中文字幕精品亚洲无线码一区| 中文亚洲av片在线观看爽| 18禁美女被吸乳视频| 国产1区2区3区精品| 国产私拍福利视频在线观看| 99久久成人亚洲精品观看| 搡老岳熟女国产| 国内精品久久久久久久电影| 男人舔奶头视频| 久久久色成人| 国产99白浆流出| 午夜福利在线观看吧| 不卡av一区二区三区| 琪琪午夜伦伦电影理论片6080| 两个人看的免费小视频| 亚洲,欧美精品.| 日韩欧美在线二视频| 国产精品久久久av美女十八| 少妇的丰满在线观看| 午夜福利在线在线| 久久久久性生活片| 国产精品影院久久| 国产精品美女特级片免费视频播放器 | 制服丝袜大香蕉在线| 麻豆一二三区av精品| 99热只有精品国产| 久久久国产成人精品二区| 日本成人三级电影网站| 天堂动漫精品| 久久久久国产一级毛片高清牌| 黄色 视频免费看| av视频在线观看入口| xxx96com| 亚洲国产精品999在线| 免费看美女性在线毛片视频| bbb黄色大片| 一级毛片女人18水好多| 午夜免费成人在线视频| 亚洲九九香蕉| 亚洲av电影不卡..在线观看| 亚洲国产高清在线一区二区三| 一个人免费在线观看的高清视频| 人妻久久中文字幕网| 在线a可以看的网站| 淫秽高清视频在线观看| 精品99又大又爽又粗少妇毛片 | 亚洲熟妇中文字幕五十中出| 久久这里只有精品19| 国产毛片a区久久久久| 老汉色av国产亚洲站长工具| 欧美一级毛片孕妇| 三级国产精品欧美在线观看 | xxx96com| 成人三级黄色视频| 精品欧美国产一区二区三| 小说图片视频综合网站| 99riav亚洲国产免费| av天堂中文字幕网| 在线观看午夜福利视频| 在线观看免费视频日本深夜| 黄片大片在线免费观看| 精品国产超薄肉色丝袜足j| 国模一区二区三区四区视频 | 在线观看日韩欧美| 成人国产一区最新在线观看| 99热6这里只有精品| 午夜视频精品福利| 久99久视频精品免费| 亚洲成人久久性| 国产欧美日韩一区二区精品| 午夜福利高清视频| 99久久国产精品久久久| 女人高潮潮喷娇喘18禁视频| 国产美女午夜福利| 在线观看66精品国产| 久久精品综合一区二区三区| 精品人妻1区二区| 在线观看午夜福利视频| 亚洲中文日韩欧美视频| 国产精品,欧美在线| 99久国产av精品| 人人妻人人澡欧美一区二区| 午夜精品久久久久久毛片777| 在线a可以看的网站| av在线天堂中文字幕| www.精华液| 亚洲 国产 在线| 国产精品 国内视频| 久久精品国产综合久久久| 精品乱码久久久久久99久播| 国产视频内射| 悠悠久久av| 成年人黄色毛片网站| 国产乱人伦免费视频| 国产三级黄色录像| 法律面前人人平等表现在哪些方面| 一区二区三区高清视频在线| 国产成人精品无人区| 怎么达到女性高潮| 久久精品夜夜夜夜夜久久蜜豆| 操出白浆在线播放| 婷婷精品国产亚洲av| 听说在线观看完整版免费高清| 欧美不卡视频在线免费观看| 国产精品香港三级国产av潘金莲| 香蕉国产在线看| 免费看光身美女| 亚洲九九香蕉| 国产成人精品久久二区二区免费| 亚洲中文字幕日韩| 在线观看美女被高潮喷水网站 | 国产激情欧美一区二区| 亚洲真实伦在线观看| 禁无遮挡网站| www日本在线高清视频| 国产精品九九99| 亚洲第一电影网av| 久久久国产欧美日韩av| 最近在线观看免费完整版| 亚洲国产高清在线一区二区三| 欧美成狂野欧美在线观看| 国产高清视频在线播放一区| 国产日本99.免费观看| 午夜影院日韩av| 免费看日本二区| 午夜a级毛片| 天堂影院成人在线观看| 99在线人妻在线中文字幕| 少妇的逼水好多| 中文字幕熟女人妻在线| 一个人看视频在线观看www免费 | 亚洲精品乱码久久久v下载方式 | 最近在线观看免费完整版| 日本免费一区二区三区高清不卡| 色视频www国产| 国产一区在线观看成人免费| 亚洲第一电影网av| 亚洲av成人av| 91九色精品人成在线观看| 日本a在线网址| 手机成人av网站| 在线观看午夜福利视频| 国产高清视频在线播放一区| 国产97色在线日韩免费| 久久这里只有精品中国| 国内精品久久久久精免费| 国产亚洲欧美在线一区二区| 亚洲专区字幕在线| 久久精品91无色码中文字幕| 麻豆久久精品国产亚洲av| 一进一出抽搐动态| 亚洲成人中文字幕在线播放| www.熟女人妻精品国产| 一二三四社区在线视频社区8| 成人欧美大片| 一个人免费在线观看电影 | 最近在线观看免费完整版| 嫩草影视91久久| 亚洲第一欧美日韩一区二区三区| 香蕉av资源在线| 免费在线观看日本一区| 久久中文字幕一级| 精品福利观看| 后天国语完整版免费观看| 欧美又色又爽又黄视频| 亚洲avbb在线观看| 亚洲18禁久久av| 中文字幕av在线有码专区| 香蕉丝袜av| h日本视频在线播放| 给我免费播放毛片高清在线观看| 成年版毛片免费区| 精品久久久久久久末码| 日韩欧美 国产精品| aaaaa片日本免费| 中文字幕人成人乱码亚洲影| 99热这里只有是精品50| 成在线人永久免费视频| 婷婷精品国产亚洲av| 后天国语完整版免费观看| 人人妻,人人澡人人爽秒播| 色综合欧美亚洲国产小说| 国产91精品成人一区二区三区| 国产探花在线观看一区二区| 黄频高清免费视频| 熟女电影av网| 亚洲欧美激情综合另类| avwww免费| 亚洲人成网站高清观看| av在线天堂中文字幕| 国产乱人伦免费视频| 精品欧美国产一区二区三| av中文乱码字幕在线| 女人被狂操c到高潮| 久久久国产欧美日韩av| 日韩三级视频一区二区三区| 欧美色视频一区免费| 国产亚洲精品久久久久久毛片| 亚洲国产精品成人综合色| 亚洲欧美日韩东京热| 91av网站免费观看| 国产激情欧美一区二区| 男女做爰动态图高潮gif福利片| 很黄的视频免费| 久久欧美精品欧美久久欧美| 性色avwww在线观看| 亚洲av片天天在线观看| 免费电影在线观看免费观看| 色av中文字幕| 亚洲成人中文字幕在线播放| 老司机午夜十八禁免费视频| 日韩欧美 国产精品| 男插女下体视频免费在线播放| 中文亚洲av片在线观看爽| 99riav亚洲国产免费| 国产乱人视频| 欧美极品一区二区三区四区| 99精品欧美一区二区三区四区| 99久久99久久久精品蜜桃| 欧美黑人巨大hd| 国产精品综合久久久久久久免费| 精品日产1卡2卡| 国产精品一区二区三区四区久久| 亚洲专区字幕在线| 十八禁人妻一区二区| 国产精品影院久久| 99久久成人亚洲精品观看| 久久久久久久午夜电影| 日韩国内少妇激情av| 毛片女人毛片| 欧美av亚洲av综合av国产av| 亚洲在线自拍视频| 性色av乱码一区二区三区2| 一区二区三区激情视频| 成人鲁丝片一二三区免费| 精品国产美女av久久久久小说| 免费一级毛片在线播放高清视频| 亚洲黑人精品在线| 大型黄色视频在线免费观看| 亚洲精品乱码久久久v下载方式 | 欧美在线一区亚洲| 午夜福利高清视频| 蜜桃久久精品国产亚洲av| 国产一区二区在线av高清观看| 岛国在线观看网站| 欧美日韩一级在线毛片| 亚洲国产看品久久| 可以在线观看毛片的网站| 69av精品久久久久久| 久久久久久人人人人人| 老司机福利观看| 国产成人福利小说| 手机成人av网站| 亚洲成人久久爱视频| 男女下面进入的视频免费午夜| 精品国内亚洲2022精品成人| 欧美在线一区亚洲| 97碰自拍视频| 中文字幕最新亚洲高清| 香蕉丝袜av| 亚洲中文字幕一区二区三区有码在线看 | 亚洲人成网站在线播放欧美日韩| 两人在一起打扑克的视频| 久久亚洲精品不卡| 中文字幕av在线有码专区| 国模一区二区三区四区视频 | 在线播放国产精品三级| 嫩草影院精品99| 熟女电影av网| 免费看日本二区| 天堂√8在线中文| 欧美不卡视频在线免费观看| 99久久国产精品久久久| 91麻豆精品激情在线观看国产| 亚洲一区二区三区不卡视频| 成年人黄色毛片网站| 欧美在线黄色| 麻豆一二三区av精品| 一边摸一边抽搐一进一小说| 精品人妻1区二区| 两个人看的免费小视频| 狠狠狠狠99中文字幕| 999久久久国产精品视频| 法律面前人人平等表现在哪些方面| 久久久久久大精品| 全区人妻精品视频| 91麻豆av在线| 成人特级av手机在线观看| 女同久久另类99精品国产91| 国产精品亚洲av一区麻豆| 久久精品影院6| 国产精品99久久99久久久不卡| 免费在线观看成人毛片| 深夜精品福利| 色老头精品视频在线观看| 无人区码免费观看不卡| 宅男免费午夜| 免费看光身美女| 亚洲熟女毛片儿| 夜夜夜夜夜久久久久| 亚洲国产欧洲综合997久久,| 国产乱人伦免费视频| 两人在一起打扑克的视频| 亚洲国产欧洲综合997久久,| 国产黄片美女视频| 国产97色在线日韩免费| АⅤ资源中文在线天堂| 国产精品98久久久久久宅男小说| 国产97色在线日韩免费| 日韩三级视频一区二区三区| 国产黄片美女视频| 日本黄色片子视频| 床上黄色一级片| 国产亚洲av高清不卡| 99久久综合精品五月天人人| 欧美性猛交黑人性爽| 精品国产超薄肉色丝袜足j| 欧美另类亚洲清纯唯美| 国产精品精品国产色婷婷| 国产99白浆流出| 欧洲精品卡2卡3卡4卡5卡区| 免费看美女性在线毛片视频| 国产高潮美女av| 午夜久久久久精精品| 最近最新中文字幕大全免费视频| 欧美又色又爽又黄视频| 精品一区二区三区av网在线观看| 啪啪无遮挡十八禁网站|