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1.
临界滑动面的获得是土质边坡稳定性分析中一个必要的过程,然而现有分析方法难以保证该临界滑面的准确性,而且部分分析方法在计算过程中会陷入局部最小值陷阱。基于单变量方法和最速梯度法,提出了交替变量局部梯度法,该方法能够突破最优化方法应用在边坡稳定性分析上的瓶颈。首先,通过斯宾塞极限平衡方法和网格搜索法（或者其他确定临界滑面的方法）,获得边坡初始椭球状临界滑面;其次,在该滑面上布置若干节点作为变量,目标函数为安全系数Fs关于空间节点坐标Zi的方程,为了使目标函数快速降低,沿负梯度方向循环优化每个节点,当满足一定精度要求时,即可获得三维土质边坡非圆弧状临界滑动面;最后,通过算例证明该方法可行,计算结果可靠。 相似文献
2.
Sumio Matsuura Takashi Okamoto Shiho Asano Hikaru Osawa Tatsuya Shibasaki 《Environmental Earth Sciences》2017,76(10):362
The displacement of a relatively small reactivated landslide in a snowy area in Japan was monitored over a long period. The displacement rate of the landslide, which was approximately of 20 mm d?1 before the formation of snow cover, decelerated drastically during the continuous snow cover period every winter period. Possible causes included reduction in the amount of water that reached the ground surface (MR: meltwater and/or rainwater) and increase in snow load. Given that the actual displacement of the landslide was far below the predicted value based on the relationship between landslide displacement and MR immediately before the continuous snow cover period, the deceleration of landslide displacement was more likely attributable to the increase in snow load than to the reduction in MR. An investigation of the link between snow load and landslide displacement showed a negative logarithmic relationship. A dynamic analysis based on the limit equilibrium method showed that snow load increases the effective normal stress and the stability of a landslide in which the mean inclination angle of the slip surface is smaller than the internal friction angle. The stability of the actual slope was also analyzed by conducting soil tests on samples collected at the site and using the resultant parameters. The analysis also showed that the increase in snow load increases the safety factor and reduces the landslide displacement. The displacement of a relatively small landslide that has a shallow slip surface was found to be greatly influenced by snow cover. 相似文献
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4.
位于四川茂县南新镇的周场坪滑坡是一大型古滑坡,曾于1982年发生大规模快速复活,目前滑体半堰塞岷江。野外地质调查表明,周场坪滑坡在平面上呈不规则长舌形,长约850 m,滑体前后缘高差约350 m;在剖面上发育3级滑动,钻探揭露滑带埋深以50~70 m为主,推测潜在失稳滑坡体积为1 500×10 4~2 000×10 4 m 3。周场坪滑坡在平面上分为4个变形区,在滑体中后部和前缘坡脚发育大量拉裂缝与下错陡坎,拉裂缝宽度以0.2~3.0 m为主,陡坎下错高度2~10 m。在野外调查和钻探分析的基础上,对该滑坡开展了地表位移(GNSS)、深部蠕滑变形(钻孔测斜仪)和雨量等监测。监测分析表明,目前周场坪滑坡后缘变形速率达0.80 m/a,中部和前缘分别为0.69 m/a和0.51 m/a,呈推移式滑动变形,整体向NW310°方向滑动;地表位移速率在监测期内基本在1~3 mm/d之间波动,波动主要受降雨量影响,且略滞后于降雨量;滑移加速度基本在0~6 mm/d 2范围波动。ZK2钻孔测斜仪监测数据表明,滑坡在80 m深度内主要沿2层滑带蠕滑,其中浅层滑带埋深在22 m左右,深层滑带埋深在46 m左右,滑移速率在0~5 mm/d范围波动。综合研究认为,周场坪滑坡目前处于缓慢变形的深层蠕滑中,其变形速率受降雨和河流侵蚀等因素的影响,在极端内、外动力条件下,可能会加速滑动,并再次整体复活,造成堵塞岷江等危害。 相似文献
5.
Finding the critical slip surface and estimating the landslide volume are of primary importance for slope seismic design. However, this may be difficult due to the uncertainty of ground motions. To address this problem, a new method for calculating uncertainties is recommended in this paper, especially for the critical slip surface and landslide volume under random earthquake ground motions. Firstly, a series of intensity–frequency nonstationary random earthquake ground motions were generated based on an improved orthogonal expansion method. A given number of potential slip surfaces were set in a soil slope. Subsequently, the factor of safety (FOS) of each slip surface for all ground motions was calculated and the minimum FOS curves were obtained. It was found that the critical slip surfaces and failure times are uncertain under different earthquakes. The Monte Carlo method was used to verify the accuracy of probability density evolution method (PDEM), and the results of the PDEM and the Monte Carlo method are consistent, meaning that the PEDM has higher computational efficiency. Moreover, the distributions of earthquake-triggered landslide volume and landslide depth were analyzed by considering equivalent extreme events. Both landslide volume and depth exhibit a normal distribution for a homogeneous soil slope. The framework of this study is meaningful for slope seismic design in engineering, for example, the location of critical slip surface can be used for slope reinforcement, and the distribution of sliding volume can be used for disaster assessment. 相似文献
6.
The Donghekou landslide-debris flow was a remarkable geological disaster triggered by the Wenchuan earthquake in 2008. The dynamic process of a rapid landslide-debris flow is very complicated and can be divided into two aspects: the slope dynamic response of the earthquake and the mass movement and accumulation process. A numerical method combined with a finite difference method (FDM) and discrete element method (DEM) for simulation of landslide-debris flow under seismic loading is presented. The FDM and DEM are coupled through the critical sliding surface, initiation time and velocity. The dynamic response of the slope is simulated by the finite difference method, and critical sliding surface is determined using the earthquake response spectrum method. The landslide initiation time and the velocity are determined by time–history analysis. The mass movement and accumulation process is simulated using the discrete element method. Simulation results demonstrate that the maximum amplification coefficient of dynamic acceleration for the Donghekou slope is approximately 3.909, the initiation time of landslide is approximately 6.0 s, and the average initial velocity of the sliding mass is approximately 0.85 m/s. The failure of the slope is the result of elevation-orientated amplification effect and the sliding mass triggered with a small initial velocity. The numerical simulated result of the maximum sliding velocity is approximately 66.35 m/s, and the mass is disintegrated rapidly because of collision and free fall. The landslide velocity decreases when the flowing mass reaches a lower slope angle and gradually comes to a stop, and the total travel distance is approximately 2400 m. 相似文献
7.
On June 14 2008, an Iwate–Miyagi inland earthquake that had a magnitude of 7.2 hit the eastern foot of the Ohu Mountains in
Tohoku district, Japan. The seismic peak ground acceleration was greater than 1,000 gal in the Aratozawa Dam area. The earthquake
triggered a massive landslide at the upper reach of the dam. The landslide had the sediment volume of over 67 million cubic
meters and is considered the largest catastrophic landslide in Japan during the last 100 years. This report presents a summary
of our findings pertinent to the landslide’s activities based on our field investigations that started the day after the landslide.
This report covers: (1) details of the land deformations caused by the landslide, (2) geological background pertinent to landslide
development, and (3) estimation of the slip surface and the other physical properties of the landslide based on the analysis
of the boring core specimens and landform features. The landslide is roughly divided into two sections, a lower and an upper
half. The lower half moved almost simultaneously as one massive block of 700 m long, 800 m wide, and 70–80 m thick. The slip
surface had developed on the very fine sand of the alternate layer of fine-grained sandstone and siltstone. The slickensided
slip surface has a gradient of only 2°. This feature indicates that the type of the landslide movement is considered to be
a block glide. The landslide body is nearly identical to the topography of the landslide area that was developed about 50,000 years ago. This shows the possibility that the landslide was reactivated. The upper half consists of two large ridges and the broad
debris field and is 600 m long, 900 m wide, and 70–100 m thick. The maximum height of the main scarp is over 150 m. 相似文献
8.
Application of large-scale ring shear tests to the analysis of tsunamigenic landslides at the Stromboli volcano, Italy 总被引：2，自引：2，他引：0
The island of Stromboli (Southern Italy) is a 4,000-m-high volcanic edifice about 900 m above sea level. Most of the NW flank
is formed by a wide scar (Sciara del Fuoco) filled by irregular alternations of volcaniclastic layers and thin lava flows.
Between 29 and 30 December 2002, a submarine and a subaerial landslide involved the northernmost part of the Sciara del Fuoco
slope and caused two tsunami waves with a maximum run-up of 10 m. Mechanisms of the rapid submarine landslide and the preceding
deformation of the subaerial and submarine slope were investigated using large-scale ring shear tests on the saturated and
dry volcaniclastic material. The shear behaviour of the material under different drainage conditions was analysed during tests
conducted at DPRI, Kyoto University. Pore pressure generation, mobilised shear strength and grain crushing, within a range
of displacements encompassing the different stages of evolution of the slope, were considered. Experimental results suggest
that even at larger displacements, shear strength of the dry material explains the virtual stability of the slope. Conversely,
full or partial liquefaction can be invoked to explain the submarine failure and the subsequent long runout (more than 1,000 m)
of the failed materials. 相似文献
9.
滑带土抗剪强度参数的三维反分析 总被引：2，自引：0，他引：2
以滑面正应力修正模式的三维边坡稳定性分析方法为基础,建立了确定滑带土抗剪强度参数的三维反分析模型。先对滑坡体的稳定性进行调查评估,确定滑坡的安全系数与三维滑面的几何尺寸;然后,通过对滑面正应力进行合理假定与修正,建立了平衡方程,以强度参数为未知数,利用数学方法并结合试验、经验等手段求解出抗剪强度参数。该模型克服了二维反分析将会高估滑带土的抗剪强度参数的缺陷,而且计算过程简单,易于编程实现。两个简单算例表明,三维反分析模型可以考虑三维滑体的空间效应,得到的抗剪强度参数更真实、更符合实际情况,为滑坡治理提供参考。 相似文献
10.
在平面应变条件下,从考虑强度折减的滑动土体极限平衡方程出发,推导出一般情况下均质土坡稳定分析的泛函极值等周模型。依据泛函取极值时必须满足的欧拉方程,通过坐标变换对变分问题求解,得到滑裂面函数及其上分布的法向应力函数。对于给定的边界条件及横截条件,土坡稳定问题转化为求解以两个拉格朗日乘子、安全系数和滑裂面一个端点的x坐标为4个未知量的函数极值问题,可以通过数值计算得到最小安全系数及所对应的最危险滑裂面。考虑坡顶拉裂缝,通过算例分析了不同的滑裂面位置及对应的安全系数。通过对ACADS边坡考题算例分析,在不考虑坡顶开裂的条件下,采用该方法的分析结果与依据极限平衡法得到的各裁判答案非常接近,在考虑坡顶开裂时,安全系数略有减小。 相似文献
11.
Evaluation of potential landslide damming: Case study of Urni landslide,Kinnaur, Satluj valley,India
This work aims to understand the process of potential landslide damming using slope failure mechanism,dam dimension and dam stability evaluation. The Urni landslide, situated on the right bank of the Satluj River, Himachal Pradesh(India) is taken as the case study. The Urni landslide has evolved into a complex landslide in the last two decade(2000-2016) and has dammed the Satluj River partially since year 2013,damaging ～200 m stretch of the National Highway(NH-05). The crown of the landslide exists at an altitude of ～2180-2190 m above msl, close to the Urni village that has a human population of about 500.The high resolution imagery shows ～50 m long landslide scarp and ～100 m long transverse cracks in the detached mass that implies potential for further slope failure movement. Further analysis shows that the landslide has attained an areal increase of 103,900 ± 1142 m^2 during year 2004-2016. About 86% of this areal increase occurred since year 2013. Abrupt increase in the annual mean rainfall is also observed since the year 2013. The extreme rainfall in the June, 2013; 11 June(～100 mm) and 16 June(～115 mm),are considered to be responsible for the slope failure in the Urni landslide that has partially dammed the river. The finite element modelling(FEM) based slope stability analysis revealed the shear strain in the order of 0.0-0.16 with 0.0-0.6 m total displacement in the detachment zone. Further, kinematic analysis indicated planar and wedge failure condition in the jointed rockmass. The debris flow runout simulation of the detached mass in the landslide showed a velocity of ～25 m/s with a flow height of ～15 m while it(debris flow) reaches the valley floor. Finally, it is also estimated that further slope failure may detach as much as 0.80 ±0.32 million m^3 mass that will completely dam the river to a height of 76±30 m above the river bed. 相似文献
12.
Stability analysis of the 2007 Chehalis lake landslide based on long-range terrestrial photogrammetry and airborne LiDAR data 总被引：1，自引：1，他引：0
Marc-André Brideau Matthieu Sturzenegger Doug Stead Michel Jaboyedoff Martin Lawrence Nicholas J. Roberts Brent C. Ward Thomas H. Millard John J. Clague 《Landslides》2012,9(1):75-91
On December 4th 2007, a 3-Mm3 landslide occurred along the northwestern shore of Chehalis Lake. The initiation zone is located at the intersection of the
main valley slope and the northern sidewall of a prominent gully. The slope failure caused a displacement wave that ran up
to 38 m on the opposite shore of the lake. The landslide is temporally associated with a rain-on-snow meteorological event
which is thought to have triggered it. This paper describes the Chehalis Lake landslide and presents a comparison of discontinuity
orientation datasets obtained using three techniques: field measurements, terrestrial photogrammetric 3D models and an airborne
LiDAR digital elevation model to describe the orientation and characteristics of the five discontinuity sets present. The
discontinuity orientation data are used to perform kinematic, surface wedge limit equilibrium and three-dimensional distinct
element analyses. The kinematic and surface wedge analyses suggest that the location of the slope failure (intersection of
the valley slope and a gully wall) has facilitated the development of the unstable rock mass which initiated as a planar sliding
failure. Results from the three-dimensional distinct element analyses suggest that the presence, orientation and high persistence
of a discontinuity set dipping obliquely to the slope were critical to the development of the landslide and led to a failure
mechanism dominated by planar sliding. The three-dimensional distinct element modelling also suggests that the presence of
a steeply dipping discontinuity set striking perpendicular to the slope and associated with a fault exerted a significant
control on the volume and extent of the failed rock mass but not on the overall stability of the slope. 相似文献
13.
Rennie B. Kaunda Ronald B. Chase Alan E. Kehew Karlis Kaugars James P. Selegean 《Environmental Earth Sciences》2010,60(7):1545-1558
A back propagation artificial neural network approach is applied to three common challenges in engineering geology: (1) characterization
of subsurface geometry/position of the slip (or failure surface) of active landslides, (2) assessment of slope displacements
based on ground water elevation and climate, and (3) assessment of groundwater elevations based on climate data. Series of
neural network models are trained, validated, and applied to a landslide study along Lake Michigan and cases from the literature.
The subsurface characterization results are also compared to a limit equilibrium circular failure surface search with specific
adopted boundary conditions. It is determined that the neural network models predict slip surfaces better than the limit equilibrium
slip surface search using the most conservative criteria. Displacements and groundwater elevations are also predicted fairly
well, in real time. The models’ ability to predict displacements and groundwater elevations provides a foundational framework
for building future warning systems with additional inputs. 相似文献
14.
物质点强度折减法及其在边坡中的应用 总被引：1，自引：0，他引：1
物质点法适用于模拟连续介质大变形,如边坡失稳全过程。在物质点法中应用强度折减法,用于边坡稳定性评价。与极限平衡法相比,二者安全系数计算值、滑动面位置结果基本一致;与有限元强度折减法相比,物质点法失稳评价标准的物理意义明确。利用物质点法大变形计算优势,评价边坡失稳后的破坏后果,通过算例说明其评价不同安全系数下的滑坡堆积形态及滑移距离的能力,尤其是评价滑坡对临近建筑物的影响程度的能力。物质点强度折减法可用于边坡稳定性评价及边坡破坏后果评价。 相似文献
15.
缓倾煤层采空区上覆山体滑坡形成机制分析 总被引：4，自引：0，他引：4
下伏采空区的缓倾斜坡,由于采空区大小、方位不同和斜坡结构特征的差异,多存在地表沉陷、拉裂、局部崩塌、滑坡等工程地质问题,常常会诱发大规模的地质灾害。马达岭滑坡发育于存在软弱夹层和煤层采空区的缓倾斜坡中,由采空区的破坏和降雨诱发形成,体积达190104m3。调查和分析表明,脆弱的地质结构和坡体下伏采空区的破坏是滑坡形成的主要原因,降雨的促进作用加速了滑坡的发生; 马达岭滑坡的破坏模式为塌落-拉裂-剪切滑移,滑坡的形成机制和发展过程可以分为以下3个阶段: 斜坡后缘拉裂阶段,滑面贯通阶段和滑坡整体破坏阶段。崩滑体崩解后顺着沟谷向下游流动,形成长1.5km的泥石流碎屑堆积区,淹没大量农田。 相似文献
16.
2015年4月11日,受持续降雨影响,三峡库区秭归县沙镇溪镇发生了大型的反倾岩质滑坡,滑坡面积约2.5×104m2,体积约25.0×104m3,造成道路及大量房屋、管道设施破坏。基于现场地质调查第一手资料,详细阐述了滑坡特殊的地质地貌及岩体结构特征,分别从地质因素和环境因素两方面进行了滑坡成因分析,基于地貌学与工程地质力学理论推断滑坡形成演化过程,并对其变形发展趋势进行了预测。得出如下结论:（1）杨家水井滑坡为持续降雨触发的牵引式反倾岩质滑坡;（2）特殊的地质构造及地形地貌条件是滑坡形成的长期孕育内在条件,持续降雨则是滑坡发生的直接诱发因素;（3）河谷下切,伴随着高应力释放及斜坡岩体卸荷回弹,层状岩体发生弯曲倾倒变形,顺向纵张节理发育,尤其是弯折带底面陡倾顺向裂隙逐步形成软弱结构面对滑坡变形失稳起着至关重要的控制作用;（4）现阶段正值汛期,后续滑坡变形以局部失稳破坏为主,而产生堰塞湖和泥石流的可能性较小,建议汛期结束后实施治理工程为宜。 相似文献
17.
公路沿线花岗岩风化区滑坡危险度评价--以日本49号国道合户地区为例 总被引：2，自引：1，他引：2
对公路沿线边坡进行稳定性评价及滑坡灾害分析，对于由滑坡、泥石流等引起的公路灾害的防治具有重要指导意义。为了评价处于花岗岩风化区的日本福岛县合户地区49号国道沿线边坡的滑坡危险程度，在调查和分析了该地区的表层破坏模式、并通过简易探测方法摸清了风化土层的厚度分布后，将研究区域划分为边坡单元(Slopeunit)，使用椭球体下半部模拟滑动面的形状，通过随机试算法确定各边坡单元危险滑动面的位置及空间形状；采用一种基于GIS的边坡稳定性三维分析模型计算各边坡单元最小安全系数以及滑坡发生概率，定量评价滑坡灾害危险程度。所有的计算过程及结果显示均在一个基于GIS平台的系统中完成，为如何利用GIS技术更好地为滑坡灾害防治工作服务拓宽了思路。 相似文献
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19.
Based on field investigation of the constituent structure and geological formation of the Maoping landslide, the authors made an in-depth study of the deformation characteristics and triggering mechanism of the reservoir-induced slide through comprehensive analysis of the about 13 years observation data. The Maoping landslide, the largest ancient landslide in Geheyan reservoir, with a volume of 23.5 million m3, is located on the left bank of the Qingjiang River, 66 km upstream of Geheyan dam. In April 1993 reservoir inundation reactivated the landslide, which resulted in relocation of a village of 290 people. Since then the landslide body has been experiencing persistent deformation with an observed maximum displacement of 2841.4 mm up to October 2005. Therefore, further development of deformation of the landslide becomes a great concern for the safety of the reservoir and dam. The analysis results show that the Maoping landslide is an ancient landslide that is an accumulation of several consequent slides along the bank slope and experienced several secondary slumps in its front in later stages. The ongoing deformation of the reactivated landslide is controlled by mechanical properties of materials and hydraulic effects induced by reservoir. The slip process is of creep deformation as a whole, and appears to be attenuating in later stage, which indicates very low possibility of the high-speed slip and integral failure of the slide. 相似文献
20.
Landslides in Sado Island of Japan: Part I. Case studies, monitoring techniques and environmental considerations 总被引：1，自引：0，他引：1
Lulseged Ayalew Hiromitsu Yamagishi Hideaki Marui Takami Kanno 《Engineering Geology》2005,81(4):419-431
A sufficient knowledge on the kinematics and development of landslides helps to adopt proper measures that can be used to protect slopes and the environment in general. This can be achieved by adequate monitoring programs. This paper presents the findings of intensive monitoring activities carried out on Shiidomari and Katanoo landslides found in Sado Island of Japan. More than one year of observation of the two landslides allowed defining some peculiar futures of their kinematics and style of development. The problem of slope instability in the two areas is generally accredited to various factors. But, both landslides were triggered by heavy rainfalls and snowmelt. Because of the outline of the area and the presence of relict topographic features, the Shiidomari landslide is considered to be a large-scale reactivation of old slope failures. The Katanoo landslide is, however, a first-time case. Geophysical investigations and drilling activities in Shiidomari indicated the presence of two slip planes. The deepest (80–100 m) of these is controlled by existing lineaments. Monitoring data suggests that the body of the landslide has subsided as much as 1.16 m just below the main scarp, but a centimeter in the central region. The toe sector also experienced a significant amount of subsidence, but this was counter-balanced by an uplift on the opposite side of the landslide. Hence, the landslide seems not any more active along the deepest slip surface, although it may extend upward and define a series of shallow shear planes around the crown. In the case of Katanoo, the landform characteristics, differential weathering, the road cut and groundwater fluctuations appeared to contribute much to determine the exact location of the landslide. Extensional cracks that preceded the landslide can be related to heavy rainfalls and the cold and warm cycles thereafter. Subsurface investigations and monitoring works indicated that the landslide has two slide blocks with different slip planes. During the observation period, the upper part of the landslide responded more effectively to rainfall and snowmelt than the middle and lower sections. The corresponding movements, however, appeared to settle about three months after failure. There were also little strain transmissions in boreholes and no significant change in the characteristics of the landslide. The kinematics of deformation of many of the slopes in Sado Island resembles that of Shiidomari landslide. But mass movements along highways and mountain roads are usually similar to Katanoo. Landslides of the type like Shiidomari may not show sudden and drastic failures, but are usually long lasting and can reactivate repeatedly along new, shallow shear planes. Monitoring works and long-term supervisions in these types of landslides are useful to identify impending failures and take the right measures before they brought about large-scale destruction to the environment. 相似文献