Stability Analysis and Design of Cantilever Retaining Walls with Regard to Possible Failure Mechanisms: An Upper Bound Limit Analysis Approach

This study presents a new algorithm for design of cantilever retaining walls based on the proposed failure mechanisms and considers the effects of wall geometric parameters using an upper-bound limit analysis approach. All previous work on this subject has only focused on the optimum design of the retaining walls assuming constant forces, irrespective of the total stability and critical conditions of failure mechanisms. In the present study, the upper-bound limit analysis method was used to determine the shape of the critical failure mechanisms for a retaining wall simultaneously with its optimal dimensions. The safety factors against overturning, sliding, and bearing capacity failure were assessed by the limit analysis approach. The current results show good agreement with the results obtained using the limit equilibrium methods and finite element analyses. The results obtained based on the proposed failure mechanism show that the geometry and dimensions of the wall affect its stability safety factors, the shape of the critical failure mechanisms and the active pressure on the wall; therefore, the process of determining the shape of the critical failure mechanisms, checking the stability of the wall and the procedure of finding its optimal dimensions should be performed simultaneously.     

综谈抗滑墙

介绍抗滑墙的种类，特点和选择原则。     

悬臂式支护结构中几种控制变形的方法

悬臂式支护结构是基坑工程中常用的支护形式,多以排桩、地下连续墙、工法桩、钢板桩等形式出现。基坑工程中在条件受限的情况下,无法做内撑,但周边部分建（构）筑物对基坑变形很敏感,需要采取一些辅助措施来控制基坑的变形。结合工程实例介绍了悬臂式支护结构中常用的几种控制变形的方法,包括双排桩外拉、锚杆（索）加固、基坑内斜撑、基坑内土加固、坑内预留反压土等,并对这几种方法的适用范围、技术要求等进行了分析,为今后类似工程的设计施工提供借鉴。     

参数法在悬臂式挡土墙底板尺寸设计中的应用

通过对悬臂式挡土墙设计特点的分析 ,提出了运用参数法进行墙趾板和墙踵板截面的设计计算 ,并进一步探讨了地基承载力对底板尺寸的影响。算例表明 ,该方法能简化设计过程 ,所得到的结果更加合理     

Internal Stability Analysis of Reinforced Earth Retaining Walls

The stabilization of slopes by the technique of reinforced earth (Terre Armée) is a very economical and reliable technique. We propose in this paper to check the overall internal stability of the reinforced earth retaining walls by three mechanical models, using the analytical method of the limit equilibrium (failure). The main objective of this paper is to compare these failure mechanical models with the failure models obtained by numerical analysis (code FLAC 2D), in order to validate the most realistic and more unfavourable failure models. Parametric and comparative studies carried out have allowed us to bring a very useful knowledge concerning the study of the internal stability of the reinforced earth retaining walls. It also proposed a theoretical mechanical model of calculation proved by numerical simulation.     

悬臂式排桩挡土墙在某铁路中的应用

本文简要介绍了悬臂式排桩挡土墙作为永久性支挡结构的设计原理、方法和施工注意事项等。     

深基坑挡土支护钻孔灌注桩设计方法

在高层建筑深基坑挡土支护后，用锚杆拉结钻孔灌注桩作挡土近年来应用的的主要方法之一。以烟台龙腈大厦深基坑挡土支护为例，介绍了用锚杆拉结的钻孔灌注桩设计方法。     

Seismic Retrofit of Gravity Retaining Walls for Residential Fills Using Ground Anchors

Failure of several gravity retaining walls in residential areas built on reclaimed land, during the October 23, 2004 Chuetsu earthquake in Niigata Prefecture, Japan, determined the authorities to consider the seismic retrofit of the walls in order to mitigate future similar disasters in the urban environment. This study addresses the effectiveness of ground anchors in improving the seismic performance of such retaining structures through a sliding block analysis of the seismic response of an anchored gravity retaining wall supporting a dry homogeneous fill slope subject to horizontal ground shaking. Sliding failure along the base of the wall and translational failure along a planar slip surface of the active wedge within the fill material behind the wall were considered in the formulation, whereas the anchor load was taken as a line load acting on the face of the gravity retaining wall. The effects of magnitude and orientation of anchor load on the yield acceleration of the wall-backfill system and seismically induced wall displacements were examined. It was found that for the same anchor orientation, the yield acceleration increases in a quasi-linear manner with increasing the anchor load, whereas an anchor load of a given magnitude acting at various orientations produces essentially identical yield accelerations. On the other hand, the computed earthquake-induced permanent displacements of the anchored gravity retaining wall decrease exponentially with increasing magnitude of anchor load. Additionally, the influence of backfill strength properties (e.g., internal friction angle) on the seismic wall displacement appears to diminish considerably for the anchored gravity retaining wall. A dynamic displacement analysis conducted for the anchored gravity retaining wall subjected to various seismic waveforms scaled to the same peak earthquake acceleration revealed a good correlation between the calculated permanent wall displacements and the Arias intensity parameter characterizing the input accelerogram.     

Seismic Passive Earth Thrust on Retaining Walls with Cohesive Backfills Using Pseudo-Dynamic Approach

In this paper, the pseudo-dynamic approach is used to estimate seismic passive earth thrust on retaining walls with cohesive-frictional backfills. The time-dependent pseudo-dynamic approach considers the influence of dynamic parameters such as the velocity of primary and shear waves, the period of lateral shaking, and the phase and amplitude variations of horizontal and vertical earthquake accelerations with depth. The failure plane behind the wall is assumed to be planar. The analysis is based on the equilibrium of forces which act within the failure wedge. The obtained results show that the backfill cohesion increases both the seismic passive earth thrust and the failure plane inclination angle with the horizontal plane. It is also observed that both horizontal and vertical seismic accelerations have decreasing effect on seismic passive earth thrust as well as failure plane inclination angle. The results of present pseudo-dynamic analysis propose a lower solution for seismic passive earth thrust compared to earlier pseudo-static solution available in the literature.     

基于遗传算法的重力式挡土墙优化设计

将遗传算法应用于重力式挡土墙截面优化设计问题的求解,并在此基础上建立了重力式挡土墙截面优化的数学模型.采用二进制编码,通过执行遗传算法的选择、交叉和变异算子,实现对重力式挡土墙截面的优化设计.算例结果表明,该优化算法用于重力式挡土墙截面优化设计是有效可行的.     

利用1stOpt软件优化设计重力式挡土墙断面

为解决挡土墙设计指标计算较为繁琐,并且难以得出最佳结果的问题,以重力式档土墙的截面面积最小为目标函数,并以满足稳定性及地基承载力验算要求为约束条件,得到非线性优化数学模型,并利用优秀国产数学软件1stopt优化求解。该方法避免了繁琐的试算过程,能得到经济合理的截面尺寸,并已成功应用在忠-武输气管线沿途水工保护工程中。     

饱水砂层深基坑中悬臂式双排桩支护及地下水处理方法

结合实例,对常用基坑支护及止水方法进行了比选,介绍了在饱水砂层深基坑中采用的悬臂式双排桩支护及高压旋喷止水帷幕技术。通过理论计算和监测数据分析了双排桩的支护效果,并探讨了高压喷射注浆止水技术在基坑支护中的应用。     

基于引力场的挡土墙设计方法研究与初步实验

传统的挡土墙设计理论存在很多缺陷,其对挡土墙工作机理的解释尚有许多争议,挡土墙失效现象时有发生。根据多年来的工程实践与理论研究,结合地球引力场理论,对挡土墙的工作机理作出了新的诠释,指出挡土墙底部与接触岩土体问的摩擦力是挡土墙稳定的关键。据此,给出了挡土墙设计的基础公式,并用实例进行了验证,从计算结果来看,引力场法的计算结果比朗肯土压力法的计算结果偏大,与预埋土压力盒的监测结果较吻合,证实该方法较切合实际。     

索道建筑基于桩锚共同作用的悬臂桩加固设计

结合武当山风景区某护坡工程,介绍了一种预应力锚索与悬臂桩（墙）组合补强加固高边坡变形的设计方案。通过对边坡地层的补充勘察,对护坡桩结构内力的受力分析,找出了高边坡变形加剧和桩身局部裂缝的原因,设计采用了预应力锚索补强加固悬臂桩（墙）。经过长期监测,加固后3年来的桩顶最大位移累计30.1 mm,小于国家规定的规范要求。实践表明,桩锚支护补强设计安全可靠,其成功经验和体会对类似项目有借鉴意义。     

长沙某高边坡支护设计优化

结合长沙某高边坡支护工程实例，详细研究边坡岩土条件及环境条件，充分挖掘岩土参数潜力：≯耋翌睾；方綦建藉蓑术、经济对比分析，优选锚杆网格梁法进行边坡加固支护。实践表明，锚杆网格梁法是一种加固高边坡性价比很好的方法。     

地连墙与自凝灰浆防水墙组合防渗新技术的应用及分析

地连墙与自凝灰浆防水墙配套使用是一种新型的深基坑支护形式,相对传统的基坑支护形式具有经济节约和防渗效果佳等优点。结合南京华新城AB地块深基坑工程应用实例,根据其复杂的工程特点,从防渗、力学性能、造价等方面论证了地连墙与自凝灰浆防渗墙配套使用的可行性及优点,并结合工程实际对自凝灰浆防渗墙的施工工艺和技术要点做了详细的介绍。     

挡土墙截面设计直接计算方法

在满足挡土墙地基承载力验算要求的基础上,推导了抗倾覆安全系数的允许取值范围表达式,同时将相关参数用截面底部宽度进行表示,并给出了换算系数的关系曲线图,进而结合抗滑移稳定性要求直接进行挡土墙截面设计。算例表明,该方法简捷直观且结果可靠,可供设计人员参考。     

大连沿海国际中心基坑支护设计

当前基坑支护设计基本以相关基坑设计软件为依托,进行极限平衡的电子计算,但是电算不能从本质上表现出受危基坑侧壁危险性与支挡结构之间的受力关系。而本文以大连星海湾沿海国际中心基坑支护设计为例,以手算的方式直观还原上述受力关系,为基坑侧壁选择支护方案。