赣南地区崩岗侵蚀的岩土特性及其成因机理研究

Collapsing erosion is the serious type of soil erosion in gannan granite area. It is necessary to catch the change law of collapse occur on an essential aspect.The growth of collapse is closely related to geotechnical engineering characteristic,wetting-drying cyclic and rainfall factor. The project develops the research on collapsing erosion genetic mechanism in gannan, on the investigation of collapsing erosion, and deeply analysing the distribute, formation, active of collapsing erosion characteristic in gannan. Collapsing erosion should investigated taking into account the wetting-drying cyclic, and establish relationship between shear strength indices and wetting-drying cyclic parameters. Analysing the geotechnical engineering characteristic of collapsing erosion, it researches the disintegration of granite weathered soil and researches collapse form mechanism at the aspect of geomechanical characteristic interaction of water and soil and researches the kinetic mechanism of collapsing erosion and researches the influence on collapsing erosion by rainfall conditions and hydrogeological Conditions. We carry out the collapse indoor simulation test, simulate the process of collapsing erosion, and analyze the developing process of cutting slope erosion under the different rainfall conditions and different terrain conditions. We research the cutting slope erosion caused by rainfall event, through setting up numerical model. We explain collapse failure mechanism by contrasting the result of numerical model with the result of indoor simulation test.It can provide a science basis for prediction, reduce prevention of collapse, and also provide a science basis of sustainnble development through proclaiming its mechanism.

崩岗侵蚀是赣南花岗岩地区土壤侵蚀最严重的类型。崩岗的发育变化与岩土工程特性、干湿循环作用及降雨等因素密切相关，有必要开展上述因素影响崩岗侵蚀的规律研究。本项目开展赣南崩岗侵蚀成因机理研究，在崩岗侵蚀的调查基础上，深入地分析赣南地区的崩岗侵蚀的分布、形态、活动状态等现状特点；进行崩岗侵蚀的岩土工程特性分析；开展干湿循环作用下崩岗侵蚀的机理研究；从岩土力学水土相互作用的角度研究崩岗侵蚀机理；研究降雨条件对崩岗侵蚀的影响。开展室内崩岗模拟试验工作，模拟崩岗侵蚀过程，分析在不同降雨条件、不同地形条件下边坡侵蚀发展过程；通过建立数值模型，研究降雨事件在坡面引起侵蚀情况，并且利用数值模拟的结果与室内模型试验结果对比分析，解释崩岗破坏的机理。通过揭示其机理，为崩岗的预测及防治提供科学依据，为实施减少侵蚀危害、改善生态环境、实施赣南等原中央苏区可持续发展的科学决策依据。

崩岗侵蚀是赣南花岗岩地区土壤侵蚀最严重的类型。崩岗的发育变化与岩土工程特性、干湿循环作用及降雨等因素密切相关，有必要开展上述因素影响崩岗侵蚀的规律研究。本项目开展赣南崩岗侵蚀成因机理研究，在崩岗侵蚀的调查基础上，深入地分析赣南地区的崩岗侵蚀的分布、形态、活动状态等现状特点；进行崩岗侵蚀的岩土工程特性分析，研究了花岗岩残积土的强度、变形、非饱和土特性、土水特征曲线等；开展干湿循环作用下崩岗侵蚀的机理研究；从岩土力学水土相互作用的角度研究崩岗侵蚀机理；采用自制的可控温度崩解试验装置进行崩岗区重塑土样的崩解试验，分析了初始含水量、干密度、PH值、干湿循环作用和温度等各因素对花岗岩残积土的崩解速率的影响，结果表明花岗岩残积土遇水易发生崩解，其崩解特性促进了土体的崩岗侵蚀发育。利用自制的土柱潜蚀实验装置，通过对不同角度及不同流量下的土柱进行了室内土柱潜蚀试验，研究表明，花岗岩残积土易发生内蚀现象，在侵蚀过程中有明显的优先流效应。利用自主设计研发的降雨模型和实验方法开展室内崩岗模拟试验工作，模拟崩岗侵蚀过程，研究降雨条件对崩岗侵蚀的影响，分析在降雨条件下花岗岩残积土边坡侵蚀发展过程；崩岗侵蚀过程可以概括为雨滴溅蚀→浸蚀→汇积侵蚀→切沟侵蚀→剥离崩塌。通过建立数值模型，研究降雨事件在坡面引起侵蚀情况，并且利用数值模拟的结果与室内模型试验结果对比分析，揭示了赣南地区崩岗侵蚀破坏的机理。通过揭示其机理，为崩岗的预测及防治提供科学依据，为实施减少侵蚀危害、改善生态环境、实施赣南等原中央苏区可持续发展的科学决策依据。