不同频度和强度的干湿循环对花岗岩红壤固结强度的影响  

Effect of wetting-drying cycles of different frequencies and intensities on consolidation intensity of granite red soil

作　　者：任秋菊 孙艺函 魏玉杰[1] 陈新 王佳鑫 刘凌志 张光辉 蔡崇法[1] REN Qiuju;SUN Yihan;WEI Yujie;CHEN Xin;WANG Jiaxin;LIU Lingzhi;ZHANG Guanghui;CAI Chongfa(College of Resources and Environment,Huazhong Agricultural University,430070,Wuhan,China;Power China Huadong Engineering Corporation,311100,Hangzhou,China)

机构地区：[1]华中农业大学资源与环境学院,武汉430070 [2]中国电建集团华东勘测设计研究院有限公司,杭州311100

出　　处：《中国水土保持科学》2024年第3期28-35,共8页Science of Soil and Water Conservation

基　　金：国家自然科学基金面上项目“花岗岩风化土体裂隙演化机制及其对崩岗侵蚀的影响”(42277329);国家自然科学基金青年科学基金项目“干湿交替作用下非均质土体的变形与失稳机制”(41807065);华中农业大学大学生创新创业训练计划项目“PAM对花岗岩残积土理化性质及作物生长的改良效应”(202210504016)。

摘　　要：南方频繁干湿交替环境是影响土体结构强度演化的重要因素。为系统探究干湿循环频度和强度对赣州花岗岩红壤固结强度的影响,本研究通过进行不同强度和频度干湿循环条件下的快速固结试验,确定干湿循环效应对固结强度变化的影响机制。结果表明:1)孔隙比随着荷载压力的增大呈现先快速减小后趋于平稳趋势,干湿循环加剧花岗岩红壤的压缩变形;2)土壤瞬时沉降量和主固结沉降量均随着干湿循环频度和强度作用增强而逐渐增加;3)花岗岩红壤干湿循环后的压缩系数在0.8~1.0之间,呈现高压缩性,且随着频度的增加压缩系数逐渐增大,7次循环后缓慢增加并趋于稳定;干湿循环频度和强度增加条件下固结系数均呈现连续下降趋势,使土体强度降低;4)干湿循环频度对固结系数和压缩系数变化作用最为显著(F=4102.71,P<0.001;F=508.40,P<0.001)。研究结果说明季节性降雨干旱引发的干湿循环效应显著影响土体的固结强度,加剧岩土体失稳崩塌的风险。[Background]Erosion-induced collapse is the most intense and severe type of erosion in the southern tropical and subtropical regions of China.The combination of abundant water and high temperatures in this region leads to variations in soil moisture due to temperature and changes in rainfall intensity and frequency.These changes result in frequent cycles of wet and dry conditions,and increase the probability of collapse.As Gan county being an area with the highest,most concentrated,and clustered erosion intensity,this study was carried out in Gan county,Jiangxi province,with the aim of providing a theoretical basis for predicting the degree of occurrence and development trend of collapse erosion.[Methods]We collected the samples from the surface granitic red soil in the Jingouxing sub-watershed characterized by a subtropical hilly-mountainous climate with concentrated rainfall from April to June,which was subjected to wetting-drying cyclic tests with different frequencies and intensities,followed by rapid consolidation tests.By analyzing the e-p curves and the amount of consolidation sedimentation,we summarized the changes in consolidation intensity of granite red soil during humidification and desiccation,as well as the change rule of consolidation intensity under different frequencies and intensities of wetting-drying cycles.[Results]1)The porosity ratio demonstrated a trend of first rapid reduction with increasing loading pressure,followed by a tendency of stabilizing.Wetting-drying cycles intensified the compression deformation of granite red.During the first 7 cycles,the porosity ratio followed the pattern of medium intensity>low intensity>high intensity.After 7 cycles,porosity showed no clear intensity-related pattern,indicating stabilization in both soil compression and deformation.2)With the increase in frequency and intensity of wetting-drying cycles,both instantaneous soil sedimentation and main consolidation sedimentation had a gradual increase.At the 10th cycle,there was a rebound in the increment of

关 键 词：花岗岩红壤 干湿循环频度 干湿循环强度 固结特性 土壤侵蚀 

分 类 号：S157.1[农业科学—土壤学]