考虑土体结构劣化的高原山区桩-土体系数值分析  

Numerical Analysis of Pile-soil System in Plateau Mountainous Areas Considering Soil Structure Deterioration

作　　者：寇海磊[1] 侯王相 荆皓 陈琦 李恒 KOU Hailei;HOU Wangxiang;JING Hao;CHEN Qi;LI Heng(College of Engineering,Ocean University of China,Qingdao 266100,China;District Power Supply Company of Lingcheng District,State Grid Shandong Electric Power Company,Dezhou 253500,China;Qingdao Construction Engineering Management and Service Center,Qingdao 266071,China)

机构地区：[1]中国海洋大学工程学院,山东青岛266100 [2]国网山东省电力公司德州市陵城区供电公司,山东德州253500 [3]青岛市建筑工程管理服务中心,山东青岛266071

出　　处：《湖南大学学报（自然科学版）》2022年第7期94-105,共12页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(52171282,51879246);西藏自治区科技计划重点研发项目(XZ202001ZY0013G);中国海洋大学山东省海洋工程重点实验室开放基金课题。

摘　　要：高原山区土体常年受冻融循环作用,结构不断劣化,导致桩-土界面作用削弱,对构筑物稳定性产生不利影响.本文开展室内试验结合数值模拟,构建了土体在冻融循环作用下的结构劣化模型,建立了考虑土体结构劣化的水-热-力耦合数学模型并验证了其可靠性.基于此,对服役期内高原山区桩-土体系稳定性进行了数值分析.试验结果表明,冻融循环条件下,土体渗透系数及孔隙比随冻融次数增加呈对数型增大,土体黏聚力随冻融次数增加呈指数型减小,内摩擦角随冻融次数增加呈对数型增大.服役期内,桩周土体最大冻胀位移随服役年限增加逐渐减小,最大融沉位移逐年增大,桩周土体整体呈融沉趋势;桩基冻胀位移随服役年限增加逐渐减小,融沉位移逐年增大,冻胀融沉增长速率不断减小,但桩基融沉位移大于其冻胀位移.试验结果可为高原山区桩基础设计提供技术支持与理论指导.Due to the perennial freezing and thawing cycles,the soil structure in plateau mountainous area deteriorates continuously,which adversely affects the pile-soil interface and the stability of structures. In this paper,the indoor laboratory tests and numerical simulation were carried out,a freezing-thawing cycle degradation model of soil structure was established,a coupled mathematical model of water-thermal-mechanics considering soil structure degradation was then established,and its reliability was also verified. Based on this,the stability of pile-soil system in plateau mountainous area during service period was numerically analyzed. The experimental results show that the soil permeability coefficient and pore ratio increase logarithmically with the number of freezing-thawing cycles,the soil cohesion decreases exponentially with the number of freezing-thawing cycles,and the internal friction angle increases logarithmically with the number of freezing-thawing cycles. During service period,the maximum frost heave displacement around soil gradually decreases with the increase of service life,and the maximum thaw settlement displacement also decreases. As a whole,the around soil shows a thaw settlement trend. The frost heave displacement of pile decreases gradually with time,the thaw settlement displacement increases as well,and the growth rate of frost heave and thaw settlement continuously decreases. However,the thaw settlement displacement of pile is larger than its frost heave displacement. Test results can supply some technical support and theoretical guidance for the design of pile foundation in plateau mountainous areas.

关 键 词：高原山区 桩基工程 冻融循环 土体结构劣化 水-热-力耦合模型 

分 类 号：TU445[建筑科学—岩土工程] TU473[建筑科学—土工工程]