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1.
降雨诱发碎石土堆积层滑坡十分普遍,野猫面滑坡则是典型的碎石土堆积型滑坡,也是三峡库区内距三峡大坝最近的
特大型滑坡体,研究其在不同降雨条件下的变形规律具有示范性和实用价值。首先,在滑坡区域地质分析的基础上,研究了碎石
土堆积层滑坡的组成结构;然后应用Modflow软件建立了滑坡地下水渗流场数值模型,对不同降雨强度和降雨历时条件下,降雨
入渗补给地下水的规律进行了模拟;最后,运用FLAC3D软件对不同降雨工况条件下,渗流场变化引起的滑坡变形规律进行了模
拟。研究结果表明:①野猫面滑坡碎石土堆积层表现为三层结构,上部为碎块石土,中下部为块石土、钙质胶结碎块石,下部滑面
为碎石土和黏土夹碎石;②降雨强度和降雨历时增加均使滑坡地下水头抬升,在斜坡前缘临近库岸部分的水力坡度明显增大;③
降雨作用下,滑坡位移量增加,变形由地表向深部、由前缘向后缘发展,在滑面处剪应变集中;极端大暴雨条件下,前缘存在整体变
形区;④碎石土堆积层滑坡地表径流疏导与生态防渗可有效防治滑坡。 相似文献
特大型滑坡体,研究其在不同降雨条件下的变形规律具有示范性和实用价值。首先,在滑坡区域地质分析的基础上,研究了碎石
土堆积层滑坡的组成结构;然后应用Modflow软件建立了滑坡地下水渗流场数值模型,对不同降雨强度和降雨历时条件下,降雨
入渗补给地下水的规律进行了模拟;最后,运用FLAC3D软件对不同降雨工况条件下,渗流场变化引起的滑坡变形规律进行了模
拟。研究结果表明:①野猫面滑坡碎石土堆积层表现为三层结构,上部为碎块石土,中下部为块石土、钙质胶结碎块石,下部滑面
为碎石土和黏土夹碎石;②降雨强度和降雨历时增加均使滑坡地下水头抬升,在斜坡前缘临近库岸部分的水力坡度明显增大;③
降雨作用下,滑坡位移量增加,变形由地表向深部、由前缘向后缘发展,在滑面处剪应变集中;极端大暴雨条件下,前缘存在整体变
形区;④碎石土堆积层滑坡地表径流疏导与生态防渗可有效防治滑坡。 相似文献
2.
顶管施工因非开挖或少开挖而在城市建设中应用广泛, 但顶管施工引起的地表沉降不容忽视。依托佛山市某电力隧道顶管工程, 通过现场实测、数值模拟及Peck经验公式的方法研究了顶管施工引起的地表沉降规律, 探讨了管-土摩擦、注浆压力及支护压力对地表沉降的影响。结果表明: 顶管施工引起的横向地表沉降在距轴线约4倍管径范围内变化较大, 管-土摩擦的改变对横向地表距轴线约3倍管径范围内的地表沉降影响较大, 对纵向地表距开挖面约1倍管径范围内的地表沉降影响较小; 注浆压力的增大能够抑制地表沉降; 支护压力的改变对横向地表距轴线约2倍管径范围内的地表沉降影响较大。研究结果可为控制顶管施工引起地表沉降措施的制定提供参考; 同时, 实测值、模拟值及Peck经验公式所得到的地表沉降变化趋势和大小相近, 验证了数值模拟及Peck经验公式在实际工程中预测地表沉降的可行性。 相似文献
3.
针对广西合山市八二路膨胀土路基,考虑采用其附近溯河矿区内煤矸石对膨胀土进行换填。通过对溯河矿区煤矸石及八二路膨胀土进行现场试验及室内实验,研究了其物理力学性质,采用数值模拟技术,探讨了煤矸石换填比例对不同含水率的膨胀土路基路面沉降的影响,取得了以下研究成果:合山地区膨胀土力学性质受其含水率的影响较大,需对膨胀土进行换填;合山市煤矸石散体级配良好,易于压实,适合用作路基填充材料;膨胀土路基在荷载作用下,路面沉降曲线整体上呈对称形式,中间部位相对于两边沉降量更大,对于半路堑路基断面形式,距道路中线同样距离的位置,路面靠近下部边坡的一侧沉降量更大;随着换填比例的增加,路面最大沉降量和差异沉降量明显减小,根据模拟结果建议将合山市八二路膨胀土路基换填3.5 m厚的煤矸石。 相似文献
4.
为研究LNAPL （轻质非水相液体）污染物在均匀含水介质中的运移规律,本文建立微元模型推导出LNAPL在均匀含水介质中的对流--弥散方程。针对不同的介质模型,对二维对流--弥散方程运用差分法进行数值模拟,求其数值解。分析LNAPL污染物的运移特征,得出在均匀介质和非均匀层状介质中运移规律： LNAPL污染物在含水介质中的运移规律遵循对流--弥散方程,介质的弥散系数是影响LNAPL污染物运移的主要因素。 相似文献
5.
万福矿井深部人工冻结粘土层的力学性状 总被引：1，自引：0，他引：1
根据万福矿井400m以下巨厚粘性土层取样进行的冻土力学性状试验结果，深部冻结粘性土的应力应变关系主要表现为应变软化特点，达到峰值应力之前显现较大幅度的屈服变形。从冻结效果看，-20℃是使深部粘性土力学性状发生明显变化的冻结状态界限值，冻结粘土样的强度明显提高，而蠕变性则明显降低，达到-20℃后，随着温度进一步降低，强度和蠕变性的变化则逐渐趋缓。 相似文献
6.
7.
在D.G.Fredlund等的非饱和土抗剪强度理论及其延伸的Rankine土压力公式以及国内学者卢肇钧等近年来的研究成果(用膨胀力代替基质吸力来刻画非饱和土的抗剪强度)的基础上,推导了含膨胀力的非饱和土竖直边坡临界高度的计算公式,初步探讨了非饱和土基坑无支护开挖深度的确定方法。 相似文献
8.
在总结前人研究的基础上,综合岩石矿物、地球化学等分析测试资料对宜昌地区五峰组-龙马溪组黑色页岩层系中笔石的赋存状态及其沉积环境进行了深入研究。结果显示:五峰组-龙马溪组黑色页岩中笔石的赋存状态存在显著差异,笔石的丰度由下至上呈现由高到低的变化趋势,硅质炭质页岩中的笔石丰度最高,以杂乱堆积为主,部分可见弱定向排列特征;灰绿色泥岩与黑色硅质页岩中笔石丰度低,以碎片为主,且硅质页岩中的笔石碎片细小。笔石的分异度在纵向上也呈现出规律性变化,赫南特阶笔石分异度最低,埃隆阶与凯迪阶对应的笔石分异度高。综合研究表明,不同笔石赋存状态所对应的有机碳质量分数w(TOC)、围岩性质、氧化还原条件、古海洋环境与水动力条件均有所差异:高笔石丰度的页岩往往对应着较高的w(TOC);石英质量分数在40%~60%的黑色页岩中笔石最为发育;笔石在弱氧化和还原环境中均能保存,但还原环境更有利于笔石的大规模富集;纵向上笔石丰度与分异度变化均受到了古环境的显著影响, 赫南特冰期造成了笔石的大量死亡和分异度的显著降低;笔石的大量混杂堆积显示悬浮沉积是主要的沉积作用方式,而定向排列的笔石应是深水底流作用的结果。基于上述页岩中笔石赋存状态差异及其沉积地质指示,深入分析了不同笔石赋存状态的沉积环境并建立了五峰组-龙马溪组沉积期的笔石堆积模式。 相似文献
9.
陕西泾阳南塬黄土滑坡滑带土残余剪切强度特性 总被引：1，自引：0，他引：1
为探求陕西泾阳南塬高速远程黄土滑坡的复活机理,从大型黄土滑坡滑带采集原状黄土试样、古土壤试样(原状土),部分制备重塑试样(重塑土),进行不同体积含水率下的反复剪切试验,从而获得滑带土残余剪切强度指标与体积含水率、黏粒含量之间的关系.结果表明:原状土和重塑土的剪应力-位移曲线均为硬化型;在不同的垂直压力下,原状土和重塑土的残余剪切强度差值变化较大;当剪切强度达到峰值强度以后,随着剪切位移的继续增大,原状土和重塑土的残余剪切强度都有一定程度的损失,这种损失因垂直压力的不同而不同;对同类土,通过反复剪切试验获得的内聚力和内摩擦角随体积含水率的增加而降低;相关性分析表明,该区滑带土的黏粒含量较低,对残余剪切强度的内摩擦角影响很小,尤其是当天然体积含水率较低时,体积含水率的变化对残余剪切强度的影响远远大于黏粒含量的影响. 相似文献
10.
针对目前盾构施工既有建（构）筑地基加固依靠经验,缺乏完善理论作为支撑的现象,有必要研究盾构掘进中、离开后既有建（构）筑地基承载力影响机理及加固后土体稳定性。为了解水泥土加固体的受剪工作状态,开展水泥土三轴试验,结果表明,当偏应力达到屈服之前,（σ1-σ3）-ε1关系近似直线,应变很小,且加固体与未加固土抗剪强度相差甚远,稳定性分析时,不考虑加固体位移及其外侧未加固土对剪力的分担。盾构掘进中,其周围土体受到挤压产生的剪应力,扩散至桩侧形成附加正摩阻力,基桩承载力提高;盾构离开后土体卸荷,桩侧产生负摩阻力,基桩承载力降低。盾构施工中加固体上段内侧受被动或主动土压力,外侧及下段受静止土压力,土压力差产生剪应力,潜在滑动界面产生拉、压应力,并导出加固后土体复合滑动面安全系数公式,通过工程实例验算加固体强度及加固后土体的稳定性。 相似文献
11.
岩体变形和破坏可以看作能量耗散和释放的过程.由于节理岩体结构复杂且难以开展室内试验,因此无法通过试验直接求取其能量学参数.基于Hoek-Brown准则和岩石能量理论,提出了节理岩体在临界状态能量学参数的估算方法.针对含贯通节理(或层面)岩体,通过修正岩块单轴抗压强度以体现贯通节理的方向效应.采用PFC3D分别模拟小尺寸岩样(Φ50mm×100mm)和大尺寸岩体(Φ2m×2m)的三轴压缩试验,通过岩石三轴试验结果拟合岩石数值模拟的细观参数并应用于节理岩体的模拟.根据节理岩体模拟得到应力应变曲线和能量流,验证了Hoek-Brown准则对节理岩体能量参数估算的合理性. 相似文献
12.
When transparent soil technology is used to study the displacement of a slope, the internal deformation of the slope can be visualized. We studied the sliding mechanism of the soil-rock slope by using transparent soil technology and considering the influence of the rock mass Barton joint roughness coefficient, angle of the soil mass, angle of the rock mass and soil thickness factors on slope stability. We obtained the deformation characteristics of the soil and rock slope with particle image velocimetry and the laser speckle technique. The test analysis shows that the slope sliding can be divided into three parts: displacements at the top, the middle, and the bottom of the slope; the decrease in the rock mass Barton joint roughness coefficient, and the increase in soil thickness, angles of the rock mass and soil mass lead to larger sliding displacements. Furthermore, we analyzed the different angles between the rock mass and soil thickness. The test result shows that the displacement of slope increases with larger angle of the rock mass. Conclusively, all these results can help to explain the soil-rock interfacial sliding mechanism. 相似文献
13.
Modelling the flexural buckling failure of stratified rock slopes based on the multilayer beam model
The buckling failure of stratified rock slopes intersected by a set of steep discontinuities that are approximately parallel to the slope surface is frequently encountered while constructing railways and roadways in mountainous areas. In this study, an analytical approach based on the energy equilibrium principle is presented to solve the flexural buckling stability of stratified rock slopes within the framework of multilayer beam theory. The generalized HoekBrown failure criterion is introduced to reflect the influences of slope size(scale effects) on the buckling stability. Subsequently, numerical and physical modellings from previous literatures are employed to validate the proposed approach. Furthermore, a practical case of Bawang Mountain landslide is also used for the comparative analysis. The study shows that the present analytical approach is capable to provide a more reasonable assessment for the buckling failure of stratified rock slopes, compared with several existing analytical approaches. Finally, a detailed parametric study is implemented, and the results indicate that the effects of rock strength, rock deformation modulus, geological strength index, layer thickness and disturbance degree of rock mass on the buckling failure of stratified rock slopes are more significant than that of rock type and slope angle. 相似文献
14.
Deformation features and failure mechanism of steep rock slope under the mining activities and rainfall 总被引：1，自引：0，他引：1
Zhi-qiang Li Yi-guo Xue Shu-cai Li Le-wen Zhang Dan Wang Bin Li Wen Zhang Kai Ning Jian-ye Zhu 《山地科学学报》2017,14(1):31-45
Underground mining activities and rainfall have potential important influence on the initiation and reactivation of the slope deformations, especially on the steep rock slope. In this paper, using the discrete element method (UDEC), numerical simulation was carried out to investigate deformation features and the failure mechanism of the steep rock slope under mining activities and rainfall. A steep rock slope numerical model was created based on a case study at the Wulong area in Chongqing city, China. Mechanical parameters of the rock mass have been determined by situ measurements and laboratory measurements. A preliminary site monitoring system has been realized, aiming at getting structure movements and stresses of unstable rock masses at the most significant discontinuities. According to the numerical model calibrated based on the monitoring data, four types of operation conditions are designed to reveal the effect of mining excavation and extreme rainfall on the deformation of the steep rock slope. 相似文献
15.
柴达木北缘奥陶纪火山作用与构造机制 总被引：4，自引：0，他引：4
柴达木北缘奥陶系海相火山岩（洋脊及洋岛火山岩组合）是柴北缘奥陶纪古洋盆存在的重要证据。奥陶纪末期，柴北缘洋盆逐渐闭合，洋壳自南向北下插到祁连陆块之下。大洋消失后，俯冲作用携带柴达木陆块继续下插，祁连陆块则自北向南道冲到柴达木陆块之上，柴北缘成为陆－陆碰撞型造山带。从而在柴达木北缘地区，自北而南形成了祁连超叠壳楔、柴北缘碰撞混杂岩带以及柴达木俯冲壳楔的三单元结构模式。 相似文献
16.
Runnels are characteristic erosional features on karstified soluble rocks and can occasionally develop on less soluble rocks (i.e. sandstones and granites) but are poorly reported in Malaysia. This research summarizes boulder distribution, size, petrology and runnel morphology in a Pleistocene post-glacial mudflow on Mount Kinabalu. The goal is to investigate the runnel formation on granites. Colonization of boulders by cyanobacteria, mosses, lichens and higher plants is observed and related to rock surface meso-scale and micro-scale features. The coarse porphyritic texture of the granite contributes to the fragmentation and mechanical weathering of large K-feldspar crystals in the runnels. The damp runnel micro-environment is preferentially covered with mosses further enhancing weathering and erosion. As runnels deepen, the remnant protruding fins of rock weaken and may break off. The runnels are subaerial pseudokarst features, not the result of dissolution. 相似文献
17.
Cracks in rock or soil slopes influence the stability and durability of the slopes. Seismic forces can trigger slope disasters, particularly in the cracked slopes. Considering the nonlinear characteristics of materials, the more generalized nonlinear failure criterion proposed by Baker is adopted. The influence of non-dimensional strength parameters on the stability of cracked slopes under earthquakes is performed using the upper bound limit analysis. The seismic displacement is calculated by adopting the logarithmic spiral failure surface according to the sliding rigid block model. Based on the existing studies, two methods for the stability analysis of cracked slopes under earthquakes are introduced: the pseudo-static method(with the factor of safety(Fs) as an evaluation index), and the displacement-based method(with the seismic displacement as an evaluation index). The pseudo-static method can only determine the instantaneous stability state of the cracked slope, yet the displacement-based methodreflects the stability variation of cracked slopes during earthquakes. The results indicate that the nondimensional strength parameters affect the factor of safety and seismic displacement of slopes significantly. The non-dimensional strength parameter(n) controlling the curvature of strength function shapes on the slope stability is affected by other parameters. Owing to cracks, the effect of non-dimensional strength parameters on seismic displacement becomes more significant. 相似文献
18.
《山地科学学报》2021,(8)
Tibetan Plateau is known as the roof of the world. Due to the continuous uplift of the Tibetan Plateau, many active fault zones are present. These active fault zones such as the Anninghe fault zone have a significant influence on the formation of special geomorphology and the distribution of geological hazards at the eastern edge of the Tibetan Plateau. The Anninghe fault zone is a key part of the Y-shaped fault pattern in the Sichuan-Yunnan block of China. In this paper, high-resolution topographic data, multitemporal remote sensing images, numerical calculations, seismic records, and comprehensive field investigations were employed to study the landslide distribution along the active part of the Anninghe. The influence of active faults on the lithology, rock mass structures and slope stress fields were also studied. The results show that the faults within the Anninghe fault zone have damaged the structure and integrity of the slope rock mass, reduced the mechanical strength of the rock mass and controlled the slope failure modes. The faults have also controlled the stress field, the distribution of the plastic strain zone and the maximum shear strain zone of the slope, thus have promoted the formation and evolution of landslides. We find that the studied landslides are linearly distributed along the Anninghe fault zone, and more than 80% of these landslides are within 2-3 km of the fault rupture zone. Moreover, the Anninghe fault zone provides abundant substance for landslides or debris flows. This paper presents four types of sliding mode control of the Anninghe fault zone, e.g., constituting the whole landslide body, controlling the lateral boundary of the landslide, controlling the crown of the landslide, and constituting the toe of the landslide. The results presented merit close attention as a valuable reference source for local infrastructure planning and engineering projects. 相似文献
19.
Rock slope stability is of great concern along highway routes as stability problems on cut slopes may cause fatal events as well as loss of property. In rock slope engineering, stability evaluations are commonly performed by means of analytical or numerical analyses, principally considering the factor of safety concept. As a matter of fact, the probabilistic assessment of slope stability is progressively getting popularity due to difficulties in assigning the most appropriate values to design parameters in analytical or numerical methods. Additionally, the effect of heterogeneities in rock masses and discontinuities on the analysis results is minimized through the probabilistic concept. In this study, slope stability of high and steep sedimentary rock cut slopes along a state highway in Adilcevaz-Bitlis (Turkey) was evaluated on the basis of probabilistic approach using the Slope Stability Probability Classification (SSPC) system. The probabilistic assessment indicates major slope stability problems because of discontinuity controlled and discontinuity orientation independent mass movements. Almost all studied cut slopes suffer from orientation-independent stability problems with very low stability probabilities. Additionally, the probability of planar and toppling failures is significantly high with respect to the SSPC system. The stability problems along the investigated rock slopes were also verified by field reconnaissance. Remedial measures such as slope re-design and reinforcement at the studied locations should be taken to prevent hazardous events along the highway. On the other hand, the probabilistic approach may be a useful tool during rock slope engineering to overcome numerous uncertainties when probabilistic and analytic results are compared. 相似文献
20.
溃屈型破坏是顺层岩质边坡一种常见的破坏模式。以大奔流顺层岩质滑坡为例，分析了其溃屈型破坏的形成机制，绿泥石片岩层面发育程度和层面抗剪强度及岩石破碎程度是大奔流滑坡发生的主要地质因素，爆破震动荷载和地下水作用是发生溃屈型破坏的主要诱发因素。基于弹性板梁稳定理论和能量平衡原理，建立了顺层岩质滑坡溃屈型破坏力学模型；通过力学分析，提出了综合考虑滑坡自重、地下水与震动荷载作用的顺层岩质滑坡溃屈段长度条件方程。以大奔流滑坡为实例进行了验算，计算结果和现场破坏特征基本一致，表明了该方法的可行性，为研究顺层岩质滑坡溃屈型破坏的力学机制提供了依据。 相似文献