地震崩滑堆积体流态化的关键组构特征及其灾变过程模拟

After Wenchuan earthquake, landslide - debris flows chains have become increasingly prominent disaster issue, that is due to the composition and structural characteristics changes of a large number of seismic collapse-landslide deposits in the valley. This research addresses the response mechanism problem of composition and structure changes leading to the critical infiltration characteristics change during the fluidization process, and takes the typical seismic gully-erosion collapse-landslide deposits as the study object, and the research methods in the study are including field testing,model experiment,sample analysis and mathematical modeling.This research first quantitatively obtains the infiltration characteristic parameters of the accumulation body in Yangjia gully in Chenjiaba Beichuan county.Then through the model controlling tests with the fine particles increasing and the porosity changing,the study can obtain the critical the infiltration parameters change data of typical earthquake deposits fluidization process.Then, based on the observation and test data, the study quantitatively reveals laws of how the key composition and structural characteristics affect the water infiltration. Finally, through mathematical modeling, the project will establish an identifying model of coupling relationship between the critical infiltration parameters and the fine particle content - porosity changes in the slumping fluidization process.The project will be quantitatively determine the critical composition and structural parameters in the seismic slumping fluidization process,and reveal the critical variations of structure factors and the interactions.The progress of the project will lay the foundation for further study on the dynamic process of the disaster chains, and also provide a theoretical reference for the mechanism of landslide fluidization.

汶川地震灾区震后滑坡-泥石流灾害链成灾问题日益突出，源于沟谷内大量崩滑堆积体组构特征的显著变化。本项目针对地震崩滑堆积体流态化中组构变化导致入渗特性改变的响应机理问题，以灾区典型沟谷侵蚀型崩滑堆积体为研究对象，采用野外观测、模型试验、样品分析和数学建模的方法，首先定量获取北川陈家坝杨家沟沟道内堆积体的入渗特征参量，通过入渗模型控制试验，获取细颗粒含量和孔隙度变化中，典型地震崩滑堆积体灾变的临界入渗参数变化数据。然后基于观测试验数据，定量揭示出崩滑堆积体流态化过程中关键组构特征对水分入渗的影响规律，最后通过数学建模，建立崩滑堆积体流态化过程中临界入渗参数与细颗粒含量和孔隙度变化的耦合关系判识模型。项目预期将定量确定地震崩滑堆积体流态化过程中的临界组构参数，并揭示各关键组构因子的变化特征及其交互影响规律，项目进展将为进一步开展灾害链动力过程研究奠定基础，对滑坡流态化链生机理研究提供理论参考。

汶川地震灾区震后滑坡-泥石流灾害链生成灾问题突出，源于沟谷内大量崩滑堆积体组构特征的显著变化。本项目针对地震崩滑堆积体流态化过程中组构变化导致入渗特性改变的响应机理问题，以灾区典型沟谷侵蚀型崩滑堆积体为研究对象，研究了地震崩滑堆积体流态化关键组构因素的确定、地震崩滑堆积体流态化的临界入渗参量的获取和崩滑堆积体入渗与关键组构因素的耦合作用关系三方面的研究内容。本项目研究成果包括以下四个方面，第一，划分了地震崩滑堆积体组构的成因分类，揭示出了地震崩滑堆积体不同成因类型的组构特征与关键控制因素；第二，通过野外对比观测试验，定量获取了不同沟道部位崩滑堆积体细颗粒组分含量的变化数据，揭示了崩滑堆积体颗粒组分在流态化过程的演化特征；第三，定量获取了在入渗试验中不同颗粒组构的堆积体入渗参量的演化特征数据，构建了崩滑堆积体流态化过程中临界入渗参数与细颗粒含量和孔隙度变化的耦合关系判识模型；第四，通过典型堆积体变形破坏的数值模拟，反演了崩滑堆积体的灾变破坏过程中受到降雨强度和降雨历时制约的响应规律。项目获取的数据、进展和成果为进一步开展地震滑坡流态化链生过程机理研究奠定了基础，也为典型滑坡-泥石流灾害链断链防灾提供参考。