• <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.

    亚洲欧美精品综合久久99| 日韩av在线免费看完整版不卡| 日本黄色片子视频| 2021少妇久久久久久久久久久| 婷婷色麻豆天堂久久 | 日韩人妻高清精品专区| 国产免费又黄又爽又色| 狂野欧美白嫩少妇大欣赏| 国产一区亚洲一区在线观看| 午夜福利高清视频| 少妇的逼水好多| 又爽又黄无遮挡网站| 嫩草影院新地址| 亚洲av男天堂| 欧美精品一区二区大全| 日韩国内少妇激情av| 最近最新中文字幕大全电影3| 国产成人aa在线观看| 亚州av有码| 国产女主播在线喷水免费视频网站 | 中文在线观看免费www的网站| 一区二区三区乱码不卡18| av又黄又爽大尺度在线免费看 | 日韩人妻高清精品专区| av在线老鸭窝| 我要看日韩黄色一级片| 久久精品国产自在天天线| h日本视频在线播放| 成人美女网站在线观看视频| 久久久久九九精品影院| 男女边吃奶边做爰视频| 婷婷色麻豆天堂久久 | 亚洲色图av天堂| 1024手机看黄色片| 99久久中文字幕三级久久日本| 成人一区二区视频在线观看| 激情 狠狠 欧美| 亚洲成人精品中文字幕电影| 黄色一级大片看看| 久久人妻av系列| a级毛色黄片| 我要搜黄色片| 成人三级黄色视频| 国产熟女欧美一区二区| 午夜视频国产福利| 秋霞在线观看毛片| 免费搜索国产男女视频| 又粗又硬又长又爽又黄的视频| av播播在线观看一区| 岛国毛片在线播放| 99久久人妻综合| 国产人妻一区二区三区在| 精品久久久久久久末码| 亚洲精品乱久久久久久| 亚洲精品亚洲一区二区| 熟妇人妻久久中文字幕3abv| 精品久久久久久久久久久久久| 亚洲欧美日韩高清专用| av在线天堂中文字幕| 高清日韩中文字幕在线| 欧美精品一区二区大全| 国产精品99久久久久久久久| 亚洲天堂国产精品一区在线| 能在线免费看毛片的网站| 久久久久久久午夜电影| 欧美日韩精品成人综合77777| 国产白丝娇喘喷水9色精品| 99热精品在线国产| 成人鲁丝片一二三区免费| 男插女下体视频免费在线播放| or卡值多少钱| 国产 一区精品| 久久久久久久久久久免费av| 精品久久久噜噜| 狂野欧美白嫩少妇大欣赏| 欧美性猛交╳xxx乱大交人| 美女国产视频在线观看| 亚洲精品乱码久久久久久按摩| 美女被艹到高潮喷水动态| 亚洲丝袜综合中文字幕| 亚洲精品456在线播放app| 男插女下体视频免费在线播放| 日本av手机在线免费观看| 亚洲精品色激情综合| 天天躁夜夜躁狠狠久久av| av.在线天堂| 国产亚洲精品av在线| 亚洲精品乱码久久久v下载方式| 成人性生交大片免费视频hd| av视频在线观看入口| 九色成人免费人妻av| 成人三级黄色视频| 天天躁夜夜躁狠狠久久av| 国产毛片a区久久久久| 中文字幕久久专区| 久久精品国产亚洲av天美| 人妻系列 视频| 99久国产av精品国产电影| 免费看美女性在线毛片视频| 变态另类丝袜制服| 看非洲黑人一级黄片| 91午夜精品亚洲一区二区三区| 欧美激情久久久久久爽电影| 小蜜桃在线观看免费完整版高清| 国产精品永久免费网站| 精品人妻熟女av久视频| 国产老妇伦熟女老妇高清| 在线观看美女被高潮喷水网站| 综合色av麻豆| 一级毛片aaaaaa免费看小| 青春草国产在线视频| 国产精品美女特级片免费视频播放器| 国语对白做爰xxxⅹ性视频网站| 久久精品久久精品一区二区三区| 欧美一区二区国产精品久久精品| 亚洲国产欧美人成| 国产国拍精品亚洲av在线观看| 色吧在线观看| 久久久成人免费电影| www.色视频.com| 亚洲av男天堂| 亚洲国产精品专区欧美| 少妇丰满av| 在线观看一区二区三区| 中文欧美无线码| 村上凉子中文字幕在线| 日本色播在线视频| 深夜a级毛片| av免费观看日本| 深夜a级毛片| 日本色播在线视频| 亚洲欧美日韩无卡精品| 免费看a级黄色片| 日日啪夜夜撸| av在线观看视频网站免费| 97人妻精品一区二区三区麻豆| 久久欧美精品欧美久久欧美| 中文天堂在线官网| 三级国产精品欧美在线观看| 亚洲精品,欧美精品| 久久精品人妻少妇| 三级国产精品欧美在线观看| 国内精品一区二区在线观看| 波多野结衣巨乳人妻| 99热这里只有是精品50| 婷婷色av中文字幕| 秋霞在线观看毛片| 亚洲成人久久爱视频| 在线观看美女被高潮喷水网站| 国产国拍精品亚洲av在线观看| 免费电影在线观看免费观看| 国产不卡一卡二| 国产精品无大码| 成人毛片60女人毛片免费| 免费av不卡在线播放| 秋霞伦理黄片| 日本三级黄在线观看| 亚洲一区高清亚洲精品| 亚洲综合精品二区| 能在线免费看毛片的网站| 91在线精品国自产拍蜜月| 国产一区二区亚洲精品在线观看| 久久久久久伊人网av| 国产伦精品一区二区三区视频9| 亚洲乱码一区二区免费版| 日韩av在线免费看完整版不卡| 小说图片视频综合网站| 三级男女做爰猛烈吃奶摸视频| 国产精品乱码一区二三区的特点| 亚洲欧美成人精品一区二区| 久久精品熟女亚洲av麻豆精品 | 中国国产av一级| 婷婷六月久久综合丁香| 国产精品国产三级国产av玫瑰| 久久99热这里只有精品18| 婷婷色综合大香蕉| www日本黄色视频网| 久久国产乱子免费精品| 免费看a级黄色片| 久久精品人妻少妇| 91久久精品电影网| 午夜福利高清视频| 日本免费一区二区三区高清不卡| 美女脱内裤让男人舔精品视频| 两性午夜刺激爽爽歪歪视频在线观看| 97超碰精品成人国产| 欧美人与善性xxx| 久久鲁丝午夜福利片| 99久久九九国产精品国产免费| www.av在线官网国产| 99久久九九国产精品国产免费| 人人妻人人澡人人爽人人夜夜 | 99热全是精品| 午夜激情欧美在线| 免费看日本二区| 婷婷色av中文字幕| 久久99热6这里只有精品| 亚洲精品国产av成人精品| 国产免费视频播放在线视频 | 全区人妻精品视频| 国产精品1区2区在线观看.| av天堂中文字幕网| 一个人免费在线观看电影| 欧美成人一区二区免费高清观看| 乱人视频在线观看| 一级二级三级毛片免费看| 少妇裸体淫交视频免费看高清| 久久6这里有精品| 亚洲婷婷狠狠爱综合网| 亚洲精品影视一区二区三区av| 六月丁香七月| 国产在视频线精品| 久久久色成人| 简卡轻食公司| 国产中年淑女户外野战色| 国产精品久久久久久精品电影小说 | 内射极品少妇av片p| 亚洲三级黄色毛片| 日本三级黄在线观看| 亚洲国产精品国产精品| 一级爰片在线观看| 午夜精品一区二区三区免费看| 联通29元200g的流量卡| 黄色欧美视频在线观看| 九九爱精品视频在线观看| 亚洲四区av| 成年女人看的毛片在线观看| 国产精品综合久久久久久久免费| 国产伦精品一区二区三区视频9| 精品国产露脸久久av麻豆 | 男女视频在线观看网站免费| 国产精品久久久久久av不卡| 国产片特级美女逼逼视频| 建设人人有责人人尽责人人享有的 | 国产女主播在线喷水免费视频网站 | 亚洲国产成人一精品久久久| 久久精品国产亚洲av天美| 亚洲天堂国产精品一区在线| 午夜精品一区二区三区免费看| 一级毛片aaaaaa免费看小| 高清视频免费观看一区二区 | 可以在线观看毛片的网站| 亚洲av成人精品一区久久| 免费一级毛片在线播放高清视频| 欧美日韩国产亚洲二区| h日本视频在线播放| 久久精品91蜜桃| 成人毛片a级毛片在线播放| 又粗又爽又猛毛片免费看| 亚洲真实伦在线观看| 国产精品无大码| 国产精品av视频在线免费观看| 亚洲一级一片aⅴ在线观看| 97在线视频观看| 女人十人毛片免费观看3o分钟| 亚洲欧美清纯卡通| 麻豆成人午夜福利视频| 人妻系列 视频| 99久久成人亚洲精品观看| 亚洲无线观看免费| 夜夜看夜夜爽夜夜摸| 2021天堂中文幕一二区在线观| 精品久久久久久久久亚洲| 久久人人爽人人爽人人片va| 丝袜美腿在线中文| 国产美女午夜福利| 一卡2卡三卡四卡精品乱码亚洲| 欧美一级a爱片免费观看看| 日本熟妇午夜| 国产一级毛片七仙女欲春2| 亚洲成人中文字幕在线播放| 国产高清视频在线观看网站| 国产一区二区在线av高清观看| 日日干狠狠操夜夜爽| 能在线免费看毛片的网站| 少妇人妻精品综合一区二区| av线在线观看网站| 91狼人影院| 国产高清不卡午夜福利| 村上凉子中文字幕在线| 国产精品国产三级国产av玫瑰| 国产高清国产精品国产三级 | 成人漫画全彩无遮挡| 毛片一级片免费看久久久久| 1024手机看黄色片| 国产av一区在线观看免费| 欧美高清成人免费视频www| 精品国产露脸久久av麻豆 | 99热全是精品| 日本三级黄在线观看| 成人欧美大片| 一个人看视频在线观看www免费| 日日撸夜夜添| 日本wwww免费看| 亚洲一级一片aⅴ在线观看| 亚洲aⅴ乱码一区二区在线播放| 人妻少妇偷人精品九色| 亚洲图色成人| 国产精品人妻久久久久久| 亚洲国产高清在线一区二区三| 欧美日韩在线观看h| 国产精品人妻久久久影院| 久久综合国产亚洲精品| 日本欧美国产在线视频| 亚洲一区高清亚洲精品| av专区在线播放| 国产老妇女一区| 国产乱人视频| 亚洲精品色激情综合| 91在线精品国自产拍蜜月| 三级国产精品片| 国产精品麻豆人妻色哟哟久久 | 成人欧美大片| 黄色日韩在线| 波多野结衣高清无吗| 精品久久久久久久久亚洲| 成年女人永久免费观看视频| 国模一区二区三区四区视频| 成人亚洲精品av一区二区| 亚洲成av人片在线播放无| 九九在线视频观看精品| 国产真实伦视频高清在线观看| 亚洲精品色激情综合| 91精品伊人久久大香线蕉| 如何舔出高潮| 亚洲国产日韩欧美精品在线观看| 欧美最新免费一区二区三区| 亚洲成人精品中文字幕电影| 国产一区二区亚洲精品在线观看| 亚洲综合精品二区| 青春草国产在线视频| 黄色欧美视频在线观看| 成年版毛片免费区| 久久99精品国语久久久| 九色成人免费人妻av| 一级毛片我不卡| 亚洲精品456在线播放app| 少妇的逼水好多| 国产精品综合久久久久久久免费| 我的女老师完整版在线观看| 日韩av在线大香蕉| 婷婷色av中文字幕| 欧美日韩国产亚洲二区| 婷婷色麻豆天堂久久 | 精品99又大又爽又粗少妇毛片| 赤兔流量卡办理| 久久精品91蜜桃| 久久99热这里只有精品18| 最近视频中文字幕2019在线8| 麻豆成人午夜福利视频| 国产大屁股一区二区在线视频| 女人久久www免费人成看片 | 亚洲成人久久爱视频| 天堂av国产一区二区熟女人妻| 夜夜看夜夜爽夜夜摸| 国产精品国产三级专区第一集| 亚洲18禁久久av| 国产人妻一区二区三区在| 特级一级黄色大片| 免费不卡的大黄色大毛片视频在线观看 | 亚洲欧洲国产日韩| 欧美性感艳星| 插阴视频在线观看视频| 欧美3d第一页| av专区在线播放| 熟女电影av网| 哪个播放器可以免费观看大片| 舔av片在线| 午夜免费激情av| 国产v大片淫在线免费观看| 看片在线看免费视频| 你懂的网址亚洲精品在线观看 | 国产淫片久久久久久久久| 欧美高清性xxxxhd video| 国产又色又爽无遮挡免| 男的添女的下面高潮视频| 精品久久久久久电影网 | 夜夜爽夜夜爽视频| 美女脱内裤让男人舔精品视频| 亚洲欧美日韩无卡精品| or卡值多少钱| 99热全是精品| 国产精品野战在线观看| 欧美激情久久久久久爽电影| 中文字幕av成人在线电影| 亚洲国产欧美在线一区| 91在线精品国自产拍蜜月| 国产亚洲一区二区精品| 啦啦啦韩国在线观看视频| 亚洲中文字幕一区二区三区有码在线看| 亚洲精品乱久久久久久| 毛片一级片免费看久久久久| 嘟嘟电影网在线观看| 久久久久免费精品人妻一区二区| 成人毛片60女人毛片免费| 国产高清视频在线观看网站| 日韩av在线大香蕉| 欧美丝袜亚洲另类| 国产精品麻豆人妻色哟哟久久 | 又爽又黄a免费视频| 国产白丝娇喘喷水9色精品| 精品一区二区免费观看| 搡老妇女老女人老熟妇| 能在线免费观看的黄片| 国产色爽女视频免费观看| 精品不卡国产一区二区三区| 特大巨黑吊av在线直播| 国产久久久一区二区三区| 大香蕉久久网| 91av网一区二区| 日韩强制内射视频| 久99久视频精品免费| 国产色爽女视频免费观看| 精品国产露脸久久av麻豆 | 成人美女网站在线观看视频| 看片在线看免费视频| 国产白丝娇喘喷水9色精品| 国产不卡一卡二| 能在线免费看毛片的网站| 久久草成人影院| 久久久精品大字幕| 精品不卡国产一区二区三区| 国产真实伦视频高清在线观看| 亚洲国产精品专区欧美| 99久久无色码亚洲精品果冻| 水蜜桃什么品种好| 国产又色又爽无遮挡免| 成人毛片60女人毛片免费| 国产一区二区在线av高清观看| 男人的好看免费观看在线视频| 真实男女啪啪啪动态图| 国语自产精品视频在线第100页| 自拍偷自拍亚洲精品老妇| 成人特级av手机在线观看| 久99久视频精品免费| 极品教师在线视频| 国产精品一区二区三区四区免费观看| 国产私拍福利视频在线观看| 色综合亚洲欧美另类图片| 亚洲欧美日韩高清专用| av在线亚洲专区| 日韩精品有码人妻一区| 午夜福利在线观看吧| 成人欧美大片| 亚洲自拍偷在线| 国模一区二区三区四区视频| 亚洲人成网站在线观看播放| www日本黄色视频网| 国模一区二区三区四区视频| 看片在线看免费视频| 亚洲自拍偷在线| 亚洲国产色片| 在线播放无遮挡| 亚洲欧美日韩无卡精品| 免费观看的影片在线观看| 亚洲av中文字字幕乱码综合| 久久久久精品久久久久真实原创| 欧美色视频一区免费| 国产激情偷乱视频一区二区| 亚洲精品久久久久久婷婷小说 | 亚洲av免费高清在线观看| 久久久久免费精品人妻一区二区| 国内揄拍国产精品人妻在线| 亚洲国产精品成人久久小说| 亚洲,欧美,日韩| 亚洲精品乱久久久久久| 麻豆精品久久久久久蜜桃| 亚洲av二区三区四区| 丰满乱子伦码专区| 麻豆av噜噜一区二区三区| 黄色一级大片看看| 天堂√8在线中文| 国产精品蜜桃在线观看| 国产午夜福利久久久久久| 天美传媒精品一区二区| 成人综合一区亚洲| 欧美日韩精品成人综合77777| 久久久国产成人免费| 看十八女毛片水多多多| 欧美一区二区国产精品久久精品| 嘟嘟电影网在线观看| 精品人妻偷拍中文字幕| 久久6这里有精品| 久久久精品大字幕| 婷婷色综合大香蕉| 国产淫片久久久久久久久| 伦理电影大哥的女人| or卡值多少钱| 十八禁国产超污无遮挡网站| 免费观看a级毛片全部| 男人和女人高潮做爰伦理| 91精品一卡2卡3卡4卡| 日韩大片免费观看网站 | 欧美高清成人免费视频www| 99热网站在线观看| 国产乱来视频区| 精品熟女少妇av免费看| 一级毛片电影观看 | 极品教师在线视频| 欧美一级a爱片免费观看看| 国产精品99久久久久久久久| 亚洲电影在线观看av| 久久久午夜欧美精品| 91aial.com中文字幕在线观看| 日韩大片免费观看网站 | 成人av在线播放网站| 国产伦在线观看视频一区| 高清av免费在线| 色尼玛亚洲综合影院| 亚洲精品久久久久久婷婷小说 | 免费黄网站久久成人精品| 日日啪夜夜撸| 亚洲欧美日韩高清专用| 天天一区二区日本电影三级| 少妇的逼好多水| 在线播放国产精品三级| 只有这里有精品99| 亚洲欧美日韩高清专用| 老司机影院毛片| 欧美一区二区亚洲| 国产精品电影一区二区三区| 九九久久精品国产亚洲av麻豆| 午夜免费男女啪啪视频观看| 国产精品国产三级专区第一集| 最近手机中文字幕大全| 日韩成人伦理影院| 97超视频在线观看视频| 国产精品伦人一区二区| 亚洲av日韩在线播放| 天天躁日日操中文字幕| 国产精品99久久久久久久久| 又粗又硬又长又爽又黄的视频| 国产 一区 欧美 日韩| www日本黄色视频网| 水蜜桃什么品种好| 夫妻性生交免费视频一级片| 超碰av人人做人人爽久久| 久久精品熟女亚洲av麻豆精品 | 91精品一卡2卡3卡4卡| www.色视频.com| 蜜桃亚洲精品一区二区三区| 在线天堂最新版资源| 97超视频在线观看视频| 国产69精品久久久久777片| 1000部很黄的大片| 日韩欧美精品免费久久| 国产综合懂色| 两个人的视频大全免费| 丝袜美腿在线中文| 久久久a久久爽久久v久久| 天天躁夜夜躁狠狠久久av| 男插女下体视频免费在线播放| 三级经典国产精品| 日本免费a在线| kizo精华| 亚洲精品乱久久久久久| 亚洲国产精品久久男人天堂| 97人妻精品一区二区三区麻豆| 国产成人aa在线观看| 成人毛片60女人毛片免费| 美女cb高潮喷水在线观看| 老司机影院毛片| 69av精品久久久久久| 麻豆成人av视频| 综合色av麻豆| 久久这里有精品视频免费| 亚洲熟妇中文字幕五十中出| 直男gayav资源| 日本wwww免费看| 亚洲美女搞黄在线观看| 热99在线观看视频| 亚洲人成网站在线播| 日本色播在线视频| 欧美丝袜亚洲另类| 日韩人妻高清精品专区| 成人性生交大片免费视频hd| 边亲边吃奶的免费视频| 国产精品熟女久久久久浪| 人体艺术视频欧美日本| 最近手机中文字幕大全| 中文亚洲av片在线观看爽| 久久久久九九精品影院| 国产极品精品免费视频能看的| 国语对白做爰xxxⅹ性视频网站| 精品国产露脸久久av麻豆 | 免费播放大片免费观看视频在线观看 | 好男人视频免费观看在线| av天堂中文字幕网| 一区二区三区乱码不卡18| 国产精品久久久久久久电影| 久久久色成人| 亚洲精品aⅴ在线观看| 日韩 亚洲 欧美在线| 2022亚洲国产成人精品| 日本黄色片子视频| 美女大奶头视频| 蜜桃亚洲精品一区二区三区| 精华霜和精华液先用哪个| 欧美成人免费av一区二区三区| 日本午夜av视频| 晚上一个人看的免费电影| 日韩中字成人| 国产91av在线免费观看| 亚洲欧美成人综合另类久久久 | 哪个播放器可以免费观看大片| 亚洲精品456在线播放app| 亚洲乱码一区二区免费版| 欧美3d第一页| 哪个播放器可以免费观看大片| 亚洲欧美精品综合久久99| 久久精品国产自在天天线| 免费看日本二区| 黄片wwwwww| 高清毛片免费看| 国产精品,欧美在线|