碎块石堆积体边坡热-气-液-固耦合灾变机理及控制研究

In the preliminary study, we find that the disaster of debris slope is caused by the interactions among hot field, gas one, fluid one and deformation one, and heavy rainfall is the most critical factor to induce the disaster of talus slope with gravel and block stone. On the basis of the preliminary study, using in-situ test, infiltration triaxial test and rheological triaxial test of unsaturated soil, and numerical simulation using the asynchronous strength reduction method of numerical manifold element and the multi-scale cascaded coupled numerical evaluation method of finite element and discrete element, the viscoelastic plasticity model of loose deposit with gravel and block stone coupling hot field, gas field, fluid field and deformation field, and the disaster probabilistic control model of talus slope, are established using unsaturated soil mechanics, rheological principles of soil mechanics, rheological damage mechanics, multi-physics coupling theory, the probabilistic control theory of nonlinear dynamics for disaster and the orthogonal experiment method. The coupled disaster effects among hot field, gas one, fluid one and deformation one, and the reason and induced conditions of disaster occurrence for talus slope with gravel and block stone are researched using the models developed in the study. From the standpoint of the coupling actions among hot field, gas one, fluid one and soil rheological damage, the disaster mechanism of talus slope with gravel and block stone will be clarified. Forthermore, the most critical induced condition and occurrence time of slope disaster will be revealed in the study. These studies have very important practical significance to explore new mechanism and new strategy for prevention and control of slope disaster. The results will provide new ideas and scientific basis to evaluate reasonably slope stability, master the dynamic evolution process of slope disaster, forecast accurately the occurrence time of slope disaster, and control and mitigate slope disaster in an economical, safety and reliable way.

雅砻江水电开发中库区两岸存在大量的碎块石堆积体边坡，严重影响着雅砻江水电工程施工期及运行期的安全。在本课题组预研究发现碎石土边坡灾变是由热场、气场、液场和形变场相互作用引起的和强降雨是诱发碎块石堆积体边坡灾变的最关键因素的基础上，本项目拟通过现场试验、非饱和土三轴渗透试验、三轴流变试验和流形元异步强度折减法、有限元与离散元多尺度级联耦合的数值模拟，运用非饱和土力学、土力学的流变原理、流变损伤力学、多场耦合理论、非线性动力学灾变概率控制理论和正交试验方法，建立碎块石堆积体热-气-液场和形变场耦合的粘弹塑性模型和边坡灾变概率控制模型，研究碎块石堆积体边坡热-气-液场和流变损伤耦合的灾变效应、灾变发生的原因和诱发条件，从热-气-液场和流变损伤耦合作用的角度，阐明碎块石堆积体边坡灾变机理，揭示边坡灾变的最关键诱发条件和发生时间，以期探寻边坡灾变的新机制和防治的新策略，为合理评价边坡稳定性、把握其成灾动态演化过程、准确预测边坡灾变发生时间以及经济、安全和可靠地控制和治理边坡灾变提供新思路和科学依据。

雅砻江水电开发中库区两岸存在大量的碎块石堆积体边坡，严重影响着雅砻江水电工程施工期及运行期的安全。本项目通过现场试验、非饱和土渗透试验、流变试验和数值模拟方法，运用非饱和土力学、土力学的流变原理、流变损伤力学、多场耦合理论、非线性动力学灾变概率控制理论和正交试验方法，建立了碎块石堆积体热-气-液场和形变场耦合的粘弹塑性模型和边坡灾变概率控制模型，研究了碎块石堆积体边坡热-气-液场和流变损伤耦合的灾变效应、灾变发生的原因和诱发条件，从热-气-液场和流变损伤耦合作用的角度，阐明了碎块石堆积体边坡灾变机理，揭示了边坡灾变的最关键诱发条件和发生时间。本项目取得的重要成果如下：开发了三维粘弹塑性热-气-液-固耦合有限元模拟评价技术和降雨作用下碎块石土边坡安全性态的动态评价技术，揭示了降雨作用下碎块石土边坡破坏过程和成灾机制，并采用流形元方法，揭示了降雨作用下塑性区贯通后碎块石土边坡的成灾过程；基于现场实时采集数据，构建了碎块石边坡灾变时间的循环神经网络模型和碎块石边坡灾变时间的连续型马尔可夫链概率模型，通过加权平均得到最终的预测模型，据此开发了一种碎块石边坡灾变险情预警预报方法；通过建立土体气-液-固-流变损伤多场耦合模型，开发了一种碎块石滑坡稳定性动态数值评价方法；基于有限差分法FLAC3D获得测点位移量，结合现场监测数据，采用神经网络、粒子群算法和NSGA-II算法，反演获取土体力学参数，据此开发了一种岩土体力学参数获取方法；采用非线性动力突变预测理论，提出了一种用于计算降雨条件下碎块石边坡失稳时间的灰色尖点突变预测模型。本项目通过探究碎块石边坡灾变的新机制和防治的新策略，为合理评价边坡稳定性、把握其成灾动态演化过程、准确预测边坡灾变发生时间以及经济、安全和可靠地控制和治理边坡灾变提供了新思路和科学依据，对该类型边坡治理和防灾减灾具有重要理论指导意义。