滑坡灾害的成因机制与力学特征及治理方法研究

Landslide disaster is one of the main disasters in our country and the world. In recent years, the Shenzhen muck landslide and Lishui landslide in Zhejiang happened in succession, causing dozens of life losses and billions of property loss. It indicates that the mechanism and the prediction of landslide disaster are not fully understood by people. One of the main reasons for landslide disaster is the lag in assessment and analysis method. The limited equilibrium method and the strength reduction method cannot fully reflect the mechanism of landslide. Therefore, this project plans to investigate the mechanism of landslide through indoor and outdoor model tests, constitutive models study and numerical methods. Based on stress field and deformation field, this project studies the formation mechanism, the progressive development, and the relation between the displacement and safety factor of landslide. The strength characteristics and stress-strain characteristics of slip soil are investigated, and its practical constitutive model would be proposed. An analysis method for slope stability based on stress field and deformation field of landslide will be presented. This method can identify the failure type of landslide quantitatively and establish the relation between deformation and safety stock, which can be applied in safety monitoring. Also, the method to identify “brittle slope” and “plastic slope” is proposed that can avoid or reduce the landslide disaster. Finally, the determination method of optimal reinforcement site of landslide is also established. Overall, the above studies of this project have theoretical significance and application value to landslide disaster treatment.

滑坡灾害仍是我国及世界上的主要灾害之一。近年我国相继发生了深圳渣土滑坡和浙江丽水滑坡造成数十人遇难和数以亿计的财产损失，说明滑坡灾害的机理及其预警仍未被人们充分认识，造成滑坡灾害的主要原因之一是目前对滑坡的评估分析手段落后，工程中常用的极限分析或强度折减法未能充分反映滑坡的机制。为此，本课题拟通过室内外模型试验、本构模型研究、数值方法等方法，研究滑坡发生的机理，利用其应力场及变形场，对滑坡的成因机制、渐进发展过程、位移与安全系数之间的关系等问题进行研究，通过研究滑带土的强度特性和应力应变特性，建立滑带土的实用本构模型；提出一套基于滑坡应力场和变形场的边坡稳定性分析方法；可以定量判断滑坡破坏的模式、建立滑坡变形与安全储备之间关系，用于安全监测预警；建立“脆性坡”和“塑性坡”的判别方法，可以避免或减少滑坡灾害；建立滑坡最优加固位置的确定方法。课题开展对滑坡灾害治理既有理论意义又有应用价值。

近年我国相继发生的深圳渣土场等滑坡灾害造成了数十人遇难和数以亿计的财产损失，说明滑坡灾害的机理及其预警仍未被人们充分认识。造成滑坡灾害的主要原因之一是目前工程中常用的极限分析或强度折减法等分析手段未能充分反映滑坡的机制。本课题采用本构理论研究、室内模型试验、数值方法等多种手段开展分析，通过研究滑带土的强度和应力应变特性，建立了滑带土的变模量本构模型；通过开展室内试验，揭示了“牵引式滑坡”和“推移式滑坡”的成因机制及渐进破坏过程；提出了一套基于变模量本构模型的边坡稳定性分析方法，并利用变模量本构模型计算边坡的应力位移场，建立位移与安全系数之间的关系，基于此提出了根据应力水平确定滑坡最优加固位置的方法。.通过研究发现，（1）与弹性本构及摩尔库伦本构相比，变模量本构能够描述岩土体的非线性变形特征，能考虑模量随应力状态的调整，能有效模拟应力释放问题，所得应力和沉降结果均与工程实际更为相符；（2）不同类型滑坡其形成发展过程不同，相应的成因机制、力学特征及稳定性变化规律也不同：推移式滑坡以剪切破坏为主，破坏首先发生于滑带中上部，而后剪切破坏单元逐步向滑带上部和坡脚方向延展，最终形成贯通的剪切破坏面，防治重点在坡腰；牵引式滑坡为剪切-张拉复合式破坏，首先是滑带中下部发生剪切破坏，逐渐扩展至滑坡中部，中上部岩土体因下部滑体滑移失去支撑发生张拉-剪切复合型破坏，防治重点在坡脚。推移式滑坡稳定性降低缓慢，有较长的缓冲时间，而牵引式滑坡稳定性降低迅速，破坏趋势一旦形成，呈不可控态势；（3）采用基于变模量本构模型计算得到的边坡应力位移场来确定加固位置及稳定性，往往能最大程度的发挥支挡结构的抗力作用，既经济又可靠。.本研究所提出的边坡稳定性分析方法及加固位置的确定方法，可以定量判断滑坡的安全储备，用于安全监测预警，避免或减少滑坡灾害。课题开展对滑坡灾害治理既有理论意义又有应用价值。