极限平衡理论下土质边坡非线性失稳灾变机理分析与滑动面位移计算

The soil properties have important influence on stability of slope under the complex conditions, and the slope destruction exhibits the non-linear and gradual characteristics. However, the existing limit equilibrium methods (LEM) have inadequate consideration on these characteristics, so they can not satisfy the need of actual projects. In this research project, the generation model for arbitrary curved slip surface of three-dimensional (3D) slope is constructed. Then, through incorporating non-linear strength criterion, establishing the calculation model of comprehensive safety factor under different strength reduction strategy, and deducing the theory solution of slip surface displacement in combination with shear stress – strain curve on the basic of limit equilibrium theory, the stability analysis method for soil slope, which is controlled by the comprehensive safety factor and slope displacement, is obtained. By applying this method, the non-linear instability disaster mechanism and internal essence of soil slope is revealed, and the gradual destruction law of slope is obtained. Meanwhile, introducing the reasonable mathematical model with consideration of soil engineering characteristic, the limit equilibrium calculation methods for slope stability under creep and strain softening condition are proposed. In addition, the model test and numerical simulation methods are used to verify the theoretical results, and the corresponding computer software is also developed. The development of this research project can realize the modular, program, and visualization of soil slope stability analysis under the complex conditions, and these results can be convenient to guide the existing soil slope safety assessment and reinforcement protection.

复杂条件下土体的自身性质对边坡稳定性影响很大，且边坡的破坏表现为非线性和渐变性等特征，然而，现有极限平衡计算方法对其考虑不足，已不能满足实际工程的需要。本项目构建三维边坡任意曲线滑动面的生成模型，并在极限平衡理论的基础上，融入非线性强度准则，建立不同强度折减策略下综合安全系数计算模式，且结合剪应力应变关系曲线推导滑动面位移理论解，进而获得综合安全系数和边坡位移双向控制的土质边坡稳定性分析方法，用于揭示土质边坡的非线性失稳灾变机理和内在本质，以及得到边坡的渐进式破坏规律。同时，考虑土的工程特性，引入合理的数学模型，提出蠕变和应变软化条件下土质边坡稳定性极限平衡计算方法。另外，模型试验和数值模拟方法被采用去对比验证理论结果，并开发相应的计算机软件。本项目研究的开展可实现复杂条件下土质边坡稳定性分析的模块化、程序化和可视化，其成果可便于指导现行土质边坡的安全评估与加固防护。

本项目基于边坡稳定性极限平衡理论，旨在土质边坡非线性失稳灾变机理分析方面开展研究，取得了预期的研究成果，完成了预期考核目标。主要研究成果如下：.(1) 基于“点生点”技术，构建了二、三维任意曲线滑动面生成模型，建立了滑动面控制方程，并针对实际工程中三维凸型和凹型边坡，改进了三维任意曲线滑动面生成方法，提出了三维凸型和凹型边坡下滑动面与坡面交点的计算算法，编制了滑动面的可视化程序；.(2) 基于滑动面应力的合理假设，根据滑动体所满足的整体力学平衡条件建立极限平衡方程，从而提出了二、三维边坡稳定性极限平衡应力分析方法，相比传统极限平衡方法，该方法具有计算过程简单、计算速度快及计算结果多样化等优点； .(3) 创新性地应用泰勒级数展开一般非线性强度准则，对展开式的高阶误差项进行忽略，代替采用线性修正展开式的常数项和线性项，由此建立一般非线性强度准则下滑动面剪应力的假设条件，进而结合边坡稳定性极限平衡应力分析方法，推导出一般非线性强度准则下边坡稳定性极限平衡解答；.(4) 在双强度参数折减技术下，建立了边坡稳定性综合安全系数计算方法，改进了传统极径法，弥补了传统极径法应用范围所存在的盲区，并得到了适用范围更广的算术平方根值法；.(5) 基于所构建的加固条件下边坡失效模式，推导得土钉、锚索和抗滑桩加固条件下边坡稳定性极限平衡解答，并绘制出边坡稳定性加固优化设计图表；.(6) 假定边坡滑动体为刚体，构建出滑动面位移与滑动体整体水平位移的关系，进而应用滑动面剪应力与剪切位移的本构模型，结合边坡稳定性极限平衡应力分析方法，推导得考虑滑动面位移时边坡稳定性极限平衡解答，并由滑动体所满足的能量平衡条件，建立了滑动体整体水平位移计算公式；.(7) 在项目执行期内（2016.09.01-2018.12.31）发表和录用学术论文15篇（SCI/EI检索论文13篇，CSCD源刊论文2篇），另有3篇SCI返修，获发明专利3项，获湖南省科学技术进步一等奖1项，获湖南省优秀博士学位论文奖1项。