边坡治理中的植物固坡法

植物固坡法是近年来国际上越来越流行的一种边坡治理方法。本文阐述了植物固坡法的基本原理和作用机理，介绍了当前国内外植物固坡工程的一般施工流程，对镇江市的边坡治理提出了建议，最后对植物固坡法的应用前景作了分析。     

边坡治理中的植物固坡法

植物固坡法是近些年来国际上越来越流的一种边坡治理方法。本文阐述了植物固坡法的基本原理和作用机理，介绍了当前国内外植物固坡工程的一般施工流程，对镇江市的边坡治理提出了建议，最后对植物固坡法的应用前景作了分析。     

建房切坡条件下边坡稳定性分析

为研究切坡建房对边坡稳定性的影响,本文通过统计分析浙江省余杭区鸬鸟镇地质灾害发育分布特征与成灾模式,概化四类具有不同坡度的斜坡模型,利用有限元极限平衡法模拟计算斜坡开挖后应力、应变分布及安全系数变化规律,借助函数曲线拟合边坡开挖进尺与安全系数间的关系,推算出斜坡开挖失稳时的开挖进尺临界值。得出以下结论:(1)未开挖状态,斜坡潜在失稳区位于坡顶处,开挖后坡脚附近失稳概率高于坡顶。(2)斜坡开挖后,坡度与开挖进尺共同影响边坡稳定性,且坡度影响大于开挖进尺。(3)误差分析发现,坡度小于20°斜坡的临界值误差较大,坡度大于20°斜坡的临界值误差较小。     

桥坡顺接工程中高边坡稳定性的三维数值模拟分析

公路、铁路等工程在穿过高边坡或山谷时多采用桥坡顺接方式通过,这类边坡在开挖卸荷、降雨及桥面荷载等因素作用下极易产生灾变且影响巨大。针对桥坡顺接工程高边坡稳定性问题,依托云（浮）-罗（定）高速公路某高边坡,开展其稳定性三维有限元数值模拟,分别探讨其开挖前、开挖后支护前、支护后运营等3个不同阶段边坡稳定性及受力情况,研究高边坡在开挖、支护及桥面荷载等作用下的力学响应及其稳定性,以及边坡变形对桥梁安全性和行车舒适性的影响。计算结果表明：开挖后坡体稳定性降低,原定支护方案在提高边坡稳定性方面作用有限,并提出改进建议; 整个坡体的稳定性主要受开挖卸荷及工程支护控制,而受桥面荷载影响较小,仅对其附近的小范围坡体影响较大。研究可为桥坡顺接高边坡工程的设计与稳定性评价提供参考。     

地下水对边坡稳定性影响的数值模拟研究

边坡的失稳与地下水有很大关系,针对这一特点,利用有限元方法分析了地下水的变化对边坡稳定性的影响,研究了在地下水作用下,边坡体内应力场及位移场的分布规律。同时采用有限元方法、瑞典圆弧法(Fellenius 法)、简化毕肖普(Bishop 法)、简布法(Janbu 法)等多种边坡稳定安全系数分析方法计算了不同地下水位条件下边坡的安全系数,综合分析地下水位变化对边坡稳定性的影响,为边坡防护体系的设计提供理论依据。     

基于MIDAS的尾矿边坡三维流固耦合稳定性分析

针对尾矿坝边坡稳定性问题,使用三维有限元软件计算,对吉林省集安石墨尾矿坝进行渗流-应力-边坡耦合分析。渗流分析基于三维介质达西定律,通过不断改进工况条件来降低浸润线溢出部位,保证坝体不会发生渗透破坏。同时,尽量降低溢出部位的应力坡降,保证坝体不会发生流砂、管涌等形式渗透破坏。在渗流计算的基础上,进行渗流-应力-边坡耦合,不断改进尾矿边坡的坡角和高度等要素,得到强度折减法下的尾矿边坡稳定性系数。通过理论计算和验证,提出了一种便于施工的排渗体布置方式,并验证了排渗体的可靠性,为尾矿坝具体施工提供了技术支持。     

降雨对土质边坡稳定性影响分析

从降雨对土体抗剪强度的影响、降雨对土体重度的影响、降雨形成的水压力及降雨对土体的化学作用四个方面分析了降雨对边坡稳定性的影响。并通过一个因降雨而失稳的滑坡实例介绍其整治措施。     

西部大峡谷温泉新址边坡稳定性分析

为温泉项目的设计施工提供地质依据,分析项目边坡地质条件,对其稳定性进行定性和定量分析.采用弹塑性Mohr-Coulomb理论和刚体极限平衡法,计算边坡在向家坝水库蓄水前后不同工况下的稳定系数.研究发现,在各极端工况下边坡稳定性系数都远大于1.15,边坡整体稳定性好.     

人工堆山边坡稳定性数值分析

镇江市蛋山堆山工程是在原蛋山废弃采石场地基上,采用建筑垃圾堆筑起一座具景观功能的新蛋山,堆土厚度最大达50m,该工程西侧地基中分布有厚度较大的软土层,勘察试验结果表明该软土层强度低,压缩性高,对新山体的变形和稳定性有很大的影响。本文以该工程为例,采用数值分析法对软土地基上人工堆山边坡的变形和稳定性进行了研究,计算时对堆土施工过程中4个阶段的岩土体变形和孔隙压力变化进行了模拟。分析结果表明:地基土层和地下水对人工边坡稳定性影响较大,随堆土高度增大,坡体内超孔隙压力值和增长幅度、土体位移均不断增大。潜在滑动面附近超孔隙压力增大最大可达150kPa,引起土体中有效应力降低,不利于边坡稳定,竣工1a后孔隙压力消散最大可达71%,消散速度较慢,土体固结变形稳定将至少需要1a以上时间。竣工时,原地表最大水平位移为91.2cm,最大垂直位移量为38.3cm,位于堆土厚度较大的8号监测点。工后边坡变形稳定后,堆土体内部自身压缩沉降量约为70cm。竣工后岩土体最大位移位置位于人工山体中部,岩土体中将发生一定的差异变形,不利于边坡稳定。最后采用有限元强度折减法计算得到边坡稳定性系数为1.28,与极限平衡法计算结果接近,表明本文计算结果可靠,可以作为工程设计和施工的依据。     

非饱和土边坡稳定分析方法探讨

在对非饱和土边坡进行稳定分析时,应该全面地考虑基质吸力对边坡稳定的贡献。首先,分别探讨了基于Fredlund非饱和土强度表达式和Bishop非饱和土有效应力强度公式将强度折减有限元法推广到非饱和土边坡稳定分析中的具体方法;然后,开发了可以考虑基质吸力两种处理方法的强度折减有限元计算程序;最后,给出了一个非饱和土边坡稳定分析的对比算例,说明了二者的不同特点。     

Numerical and analytical observations on long and infinite slopes

Interest in the mechanics of landslides has led to renewed evaluation of the infinite slope equations, and the need for a more general framework for estimating the factor of safety of long and infinite slopes involving non‐homogeneous soil profiles. The paper describes finite element methods that demonstrate the potential for predicting failure in long slope profiles where the critical mechanism is not necessarily at the base of the soil layer. The influence of slope angle is also examined in long slopes, leading to some counter‐intuitive conclusions about the impact of slope steepness on the factor of safety. Copyright © 2010 John Wiley & Sons, Ltd.     

Mesh-free analysis applied in reinforced soil slopes

One of the most applicable geotechnical structures whose analysis is carried out through iterative procedures is the reinforced soil slope. In this regard, the most successful method for the reinforced slope analysis through numerical methods is the finite element method whose updating mesh may result in some difficulties. In this study, the Natural Element Method (NEM), which is a mesh-free method, in conjunction with conventional limit equilibrium is implemented to find the slip surface in the reinforced slopes. Results demonstrate the convergence and preciseness of the present method in comparison with the other numerical methods and conventional limit equilibrium method.     

Limit analysis of the stability of slopes reinforced with anchors

An approach based on the category of upper bound theorem of limit analysis is proposed in this article to consider the reinforcing effect of one row of anchors on slope stabilization. The shear strength reduction technique is used in the determination of the safety factor of the slope. The effect of anchor reinforcement is assumed to be an external axial force applied on the slope, and in the formulas of kinematic limit analysis, the work rate done by the anchor can be calculated. So, the stability analysis can be conducted without any assumptions on the acting position and decomposition of the axial force of anchors. Results were compared with those obtained using both the limit equilibrium method and numerical method. A parametric study was carried out to illustrate the effect of anchor orientation and position on slope stabilization. Copyright © 2011 John Wiley & Sons, Ltd.     

Limit state analysis of earthen slopes using dual continuum/FEM approaches

A framework alternative to that of classical slope stability analysis is developed, wherein the soil mass is treated as a continuum and in-situ soil stresses and strengths are computed accurately using inelastic finite element methods with general constitutive models. Within this framework, two alternative methods of stability analysis are presented. In the first, the strength characteristics of the soil mass are held constant, and the gravitational loading on the slope system is increased until failure is initiated by well-defined mechanisms. In the second approach, the gravity loading on the slope system is held constant, while the strength parameters of the soil mass are gradually decreased until well-defined failure mechanisms develop. Details on applying both of the proposed methods, and comparisons of their characteristics on a number of solved example problems are presented. Copyright © 1999 John Wiley & Sons, Ltd.     

再论岩质高边坡稳定性分析方法

岩质高边坡稳定性分析是岩土工程中经典的研究课题,其假定不同,分析方法就不同。从现有稳定性分析方法中存在的问题入手,指出其存在的优劣性,在刚体极限平衡和有限元等传统边坡稳定性分析方法的基础上,提出了用有限单元法直接求解边坡稳定性。该方法的思路是用潜在滑动面上在开挖、支护完成后尚未发生滑动的所有滑面单元模拟边坡在各工况下的真实应力场和变形场,根据这个真实应力场直接计算边坡安全系数。结合现场即时监测手段和计算机仿真技术可逐步模拟边坡在分步开挖期间的稳定性。算例分析表明,该方法完善了刚体极限平衡法的不足,克服了强度折减法强度参数c、?值折减比例的难题,弥补了超载法力学方向不明确的缺陷。计算所得的边坡安全系数和稳定状态与工程实际相当接近,表明提出的方法是可靠有效的新方法,为复杂岩质边坡稳定性分析提供了新的思路和途径。     

A procedure for the design and analysis of geosynthetic reinforced soil slopes

Summary A procedure for the stability analysis and design of geosynthetic reinforced soil slopes over a firm foundation is described. Firstly the unreinforced slope is analysed, and for this a circular failure method is used which allows a surcharge load to be taken into account. Any method of slip circle analysis could be used to identify the coordinates of the centre of the slip circle, its radius and the minimum factor of safety. In this study, both internal and external stability analysis of the reinforced slope is presented. Internal stability deals with the resistance to pullout failure within the reinforced soil zone resulting from the soil/reinforcement interaction. The external stability is considered by an extension of the bilinear wedge method which allows a slip plane to propagate horizontally along a reinforcing sheet. The results for total tensile force, internal and external stability are presented in the form of charts.For given properties of soil and slope geometry, the required strength of the geosynthetic and the length of reinforcement at the top and bottom of the slope can be determined using these charts. The results are compared with the published design charts by Schmertmannet al. (1987).     

土坡稳定分析简化Bishop法的数值解

建立了适于边坡稳定分析简单的平面直角坐标系,得到了该坐标系下的边坡稳定分析瑞典圆弧法的积分表达式,与张天宝法进行了验证和对比;提出了基于边坡稳定分析简化Bishop法原理的积分法,推导了其安全系数Fs积分表达式,编制了数值积分计算和图形处理程序,并进行了工程应用,实践证明该方法的正确性。     

Limit equilibrium analysis of seismic stability of slopes reinforced with a row of piles

An approach based on the category of limiting equilibrium analysis is proposed to consider the reinforcing effect of one row of vertical piles on slope under seismic conditions. The approach is based on an uncoupled formulation in which the pile response and slope stability are considered separately. Closed‐form equations are derived, allowing the yield acceleration coefficient to be determined for giving pile characteristics. Results were compared with those obtained using another limit equilibrium method. The effects of pile location on the effectiveness of increasing seismic stability of the slope–pile system were elucidated. It was found out that the piles should be installed in the middle–upper part of the slope to achieve greatest safety, but the pile length and other possible failure modes should be checked carefully in design. Copyright © 2015 John Wiley & Sons, Ltd.     

岩质高边坡的锚固设计及其稳定性分析

通过分析岩质高边坡的稳定性,采用格构式加固设计,确定了详细的设计方案;采用有限差分方法来模拟加固方案的数值解法,建立了实际的差分模型,经过计算得出加固后的边坡滑动面消失,支护后岩质边坡的稳定性系数满足要求,边坡处于稳定,为以后实际的边坡加固工程设计和计算依据提供借鉴。