控制厚度条件下崩岗土体的裂隙演化特征  

Evolution Characteristics of Cracks in Benggang Soil Under Controlled Thickness

作　　者：王娜 王佳妮 张晓明[1] 段晓阳 WANG Na;WANG Jiani;ZHANG Xiaoming;DUAN Xiaoyang(School of Resources and Environment, Huazhong Agricultural University, Wuhan 430070)

机构地区：[1]华中农业大学资源与环境学院,武汉430070

出　　处：《水土保持学报》2021年第6期175-182,共8页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41771307,41201271);长江科学院开放研究基金项目(CKWV2017522/KY);2020年湖北省大学生创新创业训练项目(S202010504045)。

摘　　要：裂隙发育降低土体承载力、抗剪强度、凝聚力等力学特性,促使崩壁崩塌。在控制土体厚度(0.8,1.6,2.2 cm)条件下,对崩岗4层土体进行室内脱湿试验,通过相机定时定点拍照,并结合数字图像处理技术分析崩岗土体的裂隙演化特征。结果表明:(1)脱湿过程中土体变形均先产生核心收缩,后产生裂隙,且4层土中过渡层最早产生核心收缩与裂隙发育现象;(2)4层土之间,裂隙发育程度呈现为过渡层>红土层>表土层>砂土层,过渡层与砂土层的较大差异会破坏土体的稳定性,加速崩壁崩塌;(3)随着土体厚度的增加,裂隙发育现象减弱,核心收缩现象逐渐增强。对于直径为12 cm的崩岗土体,当厚度为2.2 cm时,无裂隙发育,仅产生核心收缩现象。研究结果可为研究崩壁崩塌机理、提高崩岗稳定性提供科学依据。The development of crack reduces soil bearing capacity,shear strength,cohesion and other mechanical properties,promotes wall collapse.Under the condition of controlling soil thickness(0.8 cm,1.6 cm and 2.2 cm),the indoor dehumidification test was carried out on the four layers of Benggang soil.The crack evolution characteristics of Benggang soil were analyzed by taking photos at fixed time and fixed points with a camera sand combined with digital image processing technology.The results showed that:(1)During the dehumidification process,the soil deformation first produced radial shrinkage and then the cracks developed,and the transition layer of four layers soil first produced radial shrinkage and cracks.(2)Among the four layers of soil,the degree of crack development followed the order of transition layer>laterite layer>topsoil layer>sandy layer.The large difference between transition layer and sandy layer would destroy the stability of Benggang soil and accelerate wall collapse.(3)With the increasing of soil thickness,crack development gradually weakened,and the core shrinkage phenomenon increased gradually.For the Benggang soil with a diameter of 12 cm,when the thickness was 2.2 cm,there was no crack development and only core shrinkage.The research results could provide scientific bases for studying the collapse mechanism and improving the stability of Benggang soil.

关 键 词：崩岗 厚度 裂隙 核心收缩 

分 类 号：TU443[建筑科学—岩土工程]