沟谷堆积体与微型抗滑桩群协同工作的宏细观机理及设计理论

雅砻江流域高陡边坡发育，地质地形条件复杂，沟谷堆积体结构松散，极易诱发大范围滑坡，而目前针对复杂环境下沟谷堆积体治理技术和设计计算理论的研究明显不足。以雅砻江中下游水电工程高陡边坡群典型沟谷堆积体为依托，采用超大型三轴和大型直剪试验建立粗粒土-结构接触的细观本构模型，开发考虑桩-土界面相互作用的新型接触算法和DEM-FEM耦合数值方法，探索微型抗滑桩群与沟谷堆积体协同工作的宏细观机理，利用先进的光纤光栅和PIV联合监测技术的离心试验验证数值方法；通过深入地变动参数比较研究，揭示微型抗滑桩-桩群-相邻桩群间的荷载传递机理和土拱效应机制，提出桩侧土压力分布模式。在此基础上，针对真实地形地貌特征和外荷载条件，提出不同规模（浅、中、深层）堆积体边坡的微型桩群组合模式及简化设计计算方法，从而建立抗滑微型桩群的设计理论，为地质环境脆弱西南山区水电工程开发、沟谷堆积体边坡治理和防灾减灾提供技术支持。

A wide range of landslides are easily induced due to the development of high and steep slopes in the Yalong River basin, the complex geological and topographic conditions and loose structure of talus slopes in valley. Meanwhile, the researches on the treatment technique and design theory of talus slopes in the complex environment are obviously inadequate at present. Based on the typical talus slopes encountered in the hydropower projects which are located in the middle and downstream of Yalong River, micromechanical constitutive mode of coarse soil-structural contact is established through super large-scale triaxial tests and large-scale direct shear tests, then the new contact algorithm for the interaction between pile-soil interface and the DEM-FEM coupling approach are developed to investigate the macro-meso mechanism of collaborative working between anti-slide micropiles and deposit slopes. Subsequently, the new numerical method is verified by using the geo-centrifuge modeling tests with the combination of the advanced fiber bragg grating (FBG) and the particle image velocimetry (PIV) technology; then a detailed parametric study is conducted to reveal the load transfer characteristics due to the soil arching among adjacent anti-sliding mircopiles and micropile groups, further to put forward the distribution mode of later earth pressure acting on the micropile. Based on above work, the micropile group patterns and the corresponding simplified design methods are proposed for different scales (shallow, middle and deep) talus slope in valley considering the characteristics of the actual topography and the external load conditions. And the establishment of the design of anti-sliding micropile groups can provide technical support to the development of hydropower projects, the treatment of talus slopes in valley and the disaster prevention and mitigation in the southwest mountainous areas with the fragile geologic environment.