花岗岩残积土初期崩解规律与数学形态学方法近似模拟  

Initial-disintegration analysis of granite residual soil and approximate simulation of mathematical morphology

作　　者：黎澄生 安然 舒荣军 孔令伟[1] LI Chengsheng;AN Ran;SHU Rongjun;KONG Lingwei(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049

出　　处：《岩石力学与工程学报》2020年第4期845-854,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(11672320)。

摘　　要：含水率是影响花岗岩残积土崩解特性的重要因素,其中瞬态入渗作用在崩解初期阶段是一个重要原因。为了研究崩解初期阶段的瞬态入渗作用的非饱和有效应力状态,利用数学形态学方法对崩解过程中的非饱和有效应力进行近似模拟。对不同含水率试样进行崩解试验,基于Pore Algorithm(PM)方法初步建立18格子方法计算不同饱和度下的非饱和有效应力,结合瞬态入渗方法近似模拟初期崩解过程,从非饱和有效应力角度分析崩解机制。试验及模拟结果表明:花岗岩残积土的崩解曲线具有显著的两段性,在崩解初期阶段曲线具有"S"特征,初期崩解速率随着含水率的降低而增大;模拟结果发现,试样内部的气体在瞬态入渗阶段不能及时排出,试样内部的孔隙气压快速增大并稳定于某一范围,非饱和粒间综合作用力快速衰减至0,且试样初始饱和度越低衰减速率越快;如果初始饱和度足够低,试样的非饱和粒间综合作用力在入渗的瞬间急剧变成负值,即土体内部出现张应力,若张应力大于土颗粒之间的强度,土的微观结构容易被破坏,对应于试验中的初期崩解破坏。Moisture content is an important factor affecting the disintegration characteristics of granite residual soil,and transient infiltration is an important reason for initial disintegration. In order to better understand the unsaturated effective stress state of granite residual soil under transient infiltration in the initial stage of disintegration,the unsaturated effective stress in the disintegration process was approximately simulated by mathematical morphological method. The disintegration tests on different water content samples were carried out,and the unsaturated effective stress under different saturations was calculated by 18-lattice method based on the Pore Algorithm(PM) method. The approximate simulation of initial disintegration process was performed in combination with transient infiltration method,and the disintegration mechanism was analyzed from the perspective of unsaturated effective stress. The experimental results show that the disintegration curve of granite residual soil has significant two-stage characteristics and presents a"S"shape in the initial stage of disintegration. The initial disintegration rate increases with decreasing the water content. The simulation results show that the gas inside the sample can not be exhausted in time during the transient infiltration stage,resulting in that the pore pressure inside the sample increases rapidly and tends to be stable in a certain range,and that the synthetic unsaturated force between particles rapidly decays to zero and the decay rate is faster with a lower initial saturation. If the initial saturation is low enough,the synthetic unsaturated force will suddenly become negative at the moment of infiltration,that is,a tensile stress occurs inside the soil. If the tensile stress is greater than the strength between soil particles,the microscopic structure of the soil will be destroyed,which corresponds to the initial disintegration failure.

关 键 词：岩石力学 残积土 崩解 Pore Algorithm方法 非饱和有效应力 

分 类 号：TU45[建筑科学—岩土工程]