【作者】 胡启军；

【导师】 谢强；

【作者基本信息】 西南交通大学 ， 道路与铁道工程， 2008， 博士

【摘要】 现有的顺层边坡推力计算方法是考虑整个滑体计算推力，基于此方法计算长大顺层边坡的推力，得到的下滑力太大，一般支挡建筑物很难满足要求。经调查发现，长大顺层边坡失稳并非整体一次下滑，而是多次分段滑移，这样就可考虑只对首段滑移滑体加固，但此种方法现在还没有理论根据。可见，长大顺层边坡的加固设计不但关系到边坡的稳定和安全，也直接关系到整个工程造价，研究长大顺层边坡的滑移失稳机理及首段滑移长度对确定合理的加固设计方案具有非常重要的意义。本论文对长大顺层边坡滑移失稳过程进行了系统的分析，首次揭示了长大顺层边坡滑移失稳机理，初步建立了长大顺层边坡的首段滑移长度公式，首次提出了基于长大顺层边坡滑移失稳机理的长大顺层边坡加固设计原则，补充完善现有的边坡设计理论。论文遵循“现场调查-理论分析-数值分析-模型试验-现场监测”多种研究手段相结合原则，主要研究内容与研究结果如下：（1）综合考虑顺层边坡的渐进滑移失稳机理与加固难度，从工程的角度将坡长大于100m的顺层边坡定义为长大顺层边坡。（2）系统分析总结了软弱夹层弹塑性特征、峰残强度特征，结构面摩擦机理、剪切特征，获得了长大顺层边坡的滑面的力学参数特征；对滑面的应力特征进行详细分析，对影响滑面应力集中段长度的各种因素进行分析，包括坡度、坡长、滑体厚度等，揭示了各种影响因素下滑面应力集中段长度的变化规律；根据不同影响因素下滑面应力集中段长度的变化规律，提出长大顺层边坡滑面应力集中段长度的计算公式：L_max=0．3938α+0．0643 14L+1．505569H-2．18222α≤35⁰ H≤40m 100m≤L≤1000m（3）设计制作了模拟长大顺层边坡滑移失稳的模型试验装置，通过模型试验模拟了长大顺层边坡破坏形态及其演化过程，深入分析了首次滑移失稳长度与坡长及滑体厚度的关系，得到了长大顺层边坡滑移基本特征，并与滑面应力集中段长度的关系式对比分析，得到了应力集中段长度确定首段滑移长度是合理的，且具有一定的安全度。（4）通过对五个长大顺层边坡工程实例的地质调查，得到了长大顺层边坡实际的首段滑移长度，实测边坡几何参数，计算得到应力集中段长度，对比分析实际首段滑移长度与应力集中段长度，结果表明，滑面应力集中段长度可作为长大顺层边坡加固设计时加固段的长度。（5）对长大顺层边坡的设计原则进行了系统深入的研究，初步建立了一套长大顺层边坡的设计原则。该原则分四个阶段：拟开挖坡体稳定性评价阶段；岩体力学参数综合取值阶段；长大顺层边坡分类阶段；长大顺层边坡设计阶段。（6）首次提出了一种确定长大顺层边坡滑面力学参数的综合集成方法，即通过大剪试验、现场调查反分析、工程类比、规范规定并结合专家经验来综合确定长大顺层边坡滑面参数的方法，确定了综合集成方法中各种方法对滑面力学参数的取值原则。运用该方法得到了宜万铁路主要岩性滑面的力学参数的取值范围。（7）基于滑面似摩擦角的大小与岩层倾角的关系，初步将长大顺层边坡分为三类：整体稳定、渐进失稳与整体失稳。分析得到了长大顺层边坡支护结构侧向岩石压力计算式，计算式中滑面似摩擦角取滑面残余强度参数。（8）以宜万铁路巴东车站长大顺层边坡为例，利用本文加固设计原则，对该长大顺层边坡进行了加固设计。通过在此边坡的坡体与支护结构上埋设监测仪器，监测得到了长大顺层边坡的变形规律与应力变化规律；现场监测得到的边坡变形段长度与滑面应力集中段长度基本相符合，符合应力与应变相对应的原则；通过岩体压力与桩体变形反分析首段滑移长度，获得了巴东车站长大顺层边坡的安全度为2．16。表明此时巴东车站长大顺层边坡不但稳定，且具有较大的安全度，证明本文提出的长大顺层边坡加固设计原则是合理的。本文提出的长大顺层边坡加固设计原则具有清楚的理论根据，可用于工程实践。更多还原

【Abstract】 In current calculation method of thrusting force for large consequent slope, the whole gliding mass is considered. In this situation, the thrust force is too large to make the general supporting structure meet the demand of design. Investigation shows that many large consequent slopes fail not as a whole but partly in one time. So it is suggested that if the first part of the consequent slope is reinforced, the slope will be safe. But this design concept is lack of theoretical supporting. The reinforcing design of large consequent slope has great effect on stability of slope; it also affects the cost of engineering. To study the mechanism of failure of large consequent slope and the length of first failing part is very important to determine a rational reinforcing design. In this paper, the failing process and mechanism of large consequent slope are analyzed systemically. A preliminary calculation formula of first failing part of large consequent slope is obtained. The reinforcing design principle based on the failing mechanism of large consequent slope is put forward, and the present design theory is supplemented and perfected. Based on field investigation, numerical analysis, model test, field survey and field monitoring, the contents of this paper are as follows:（1） Considered the progressive failing mechanism and reinforcing difficulty of consequent slope, the slope whose length is longer than 100 m is defined as consequent slope in this paper based on the point of view of engineering.（2）The characteristic of the elastic-plasticity of weak intercalated layer, peak-residual strength, friction mechanism of structural plane and shear property is systemically analyzed and summarized. The mechanics parameter of sliding surface of large consequent slope is obtained. The stress character of sliding surface is analyzed in detailed. The influence factors that affect the length of stress concentration on sliding surface are analyzed. Those factors include slope angle, slope length, thickness of slide body and so on. A length calculation formula of stress concentration segment of sliding surface in large consequent slope is put forward as following:L_max=0．3938α+0．0643 14L+1．505569H-2．18222α≤35⁰ H≤40m 100m≤L≤1000m（3）A model to stimulate the slide mechanism of large consequent slope is designed and established. The failure mode and failing process are stimulated through model test. The relation between the length of the first part of failing slope and length of slope and thickness of slope is obtained. The result is compared with the result from the length calculation formula of stress concentration segment of sliding surface, which shows that it is rational to determine the length of the first part of failing slope by the length calculation formula of stress concentration segment of sliding surface.（4） By field geologic investigation, the lengths of the first part offailing slope of five large consequent slopes are obtained. The geometric parameters of those slopes are measured in field and the lengths of stress concentration segment are calculated. The result shows the length of stress concentration can be the basis for reinforcing design for large consequent slope.（5） The design principle of large consequent slopes is systemically studied. And a preliminary design principle for large consequent slopes is established. The design principle is divided into four steps: the step of excavation stability valuation of slope, the step of rock mass mechanics parameter value collection, the step of slope classification and the step of design.（6） A comprehensive integrated method for determining mechanical parameter of sliding surface of large consequent slope is put forward. That is to determine mechanical parameter by large-sized shear test, back analysis based on field investigation, engineering analogy, code requirement and engineering experience of experts. Applied this method in large consequent slopes in Yichang-Wanzhou railway, the value range of mechanical parameter of sliding surface is obtained.（7） Based on the relationship between comprehensive friction angle and dip angle of rock stratum, the large consequent slope can be divided into three types: the overall stable, the progressive failure and the overall failure. The calculation formula for side pressure of rock mass against supporting structure for the large consequent slope is obtained, and in the formula, the comprehensive friction angle of sliding surface equals to residual strength parameter.（8） Taking Badong slope in Yichang-Wanzhou railway as an example, the reinforcing measure of this large consequent slope is designed based on the supporting principle in this paper. By field monitoring, the deformation and stress character of the slope rock mass is obtained, and the length of deformed section by field monitoring is similar to the length of stress concentration segment. By back analysis of the first part of sliding body based on rock pressure and pile deformation, the degree of safety of the BaDong large consequent slope, which is 2.16, is obtained, which shows that the reinforcing design principle in this paper is rational.The reinforcing design principle in this paper is supported by clear theory. It can be applied to engineering practices.更多还原