水泥土强度特性和损伤本构模型研究  

Study on Strength Characteristics and Damage Constitutive Model of Cemented Soil

作　　者：陈鑫 张泽 李东庆[1] CHEN Xin;ZHANG Ze;LI Dongqing(State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Cold Regions Engineering,Science and Technology/School of Civil engineering,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049 [3]东北林业大学寒区工程与科学技术研究院/土木工程学院,黑龙江哈尔滨150040

出　　处：《湖南大学学报（自然科学版）》2020年第7期109-119,共11页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(41771078);冻土工程国家重点实验室自主研究项目(SKLFSE-ZT-19);雅砻江流域水电开发有限公司科学技术项目(YLLHK-LHA-2019006)。

摘　　要：为探究围压对水泥土强度特性的影响以及建立不同围压影响下的损伤本构模型,开展室温和冻结状态不同围压下三轴剪切试验.考察了围压对水泥土力学参数的影响规律,建立能够反映出低围压对冻结水泥土强度的强化作用和高围压的弱化作用的修正Hoek-Brown强度准则.假设水泥土微元强度的分布规律服从双参数的Weibull函数,基于Hoek-Brown强度准则和其修正形式分别确定室温和冻结状态下水泥土微元强度,建立了考虑围压的统计损伤本构模型.结果表明,基于Hoek-Brown强度准则和其修正形式建立的损伤本构模型能够较好地描述室温和冻结状态下水泥土应力-应变曲线,且能够反映出冻结状态水泥土低围压下的应变软化现象与高围压下的应变硬化现象.室温状态时不同围压下损伤变量随轴向应变变化曲线形状相似,均随轴向应变增加呈"S"型单调递增.冻结状态下低围压抑制水泥土损伤劣化程度;高围压使其损伤劣化程度增加,在轴向应变很小时,损伤变量就达到较大值.In order to investigate the influence of confining pressure on strength characteristics of cemented soil and establish a damage constitutive model under different confining pressures,triaxial shear tests under different confining pressures at room temperature and freezing state were carried out.The influence of confining pressure on mechanical parameters of cement soil was investigated.A modified Hoek-Brown strength criterion which can reflect the strengthening effect of low confining pressure and the weakening effect of high confining pressure on the strength of frozen cement soil was established.It is assumed that the distribution law of cement soil micro-element strength obeys the two-parameter Weibull function.Based on the Hoek-Brown strength criterion and its modified form,the micro-element strength of cement soil at room temperature and frozen state is determined,respectively,and the statistical damage constitutive model considering the influence of confining pressure is established.The results show that the damage constitutive model based on Hoek-Brown strength criterion and its modified form can describe the stress-strain curves of cement soil at room temperature and freezing state,and can reflect the strain softening phenomenon under low confining pressure and strain hardening phenomenon under high confining pressure.Under different confining pressures at room temperature,the damage variables change with the axial strain in a similar shape,showing a monotonic"S"pattern as the axial strain increases.Low confining pressure inhibits the damage and deterioration of cement soil under freezing condition.High confining pressure increases the degree of damage deterioration,and the damage variable reaches a larger value when the axial strain is very small.

关 键 词：水泥土 强度 应力应变关系 HOEK-BROWN强度准则 损伤本构模型 

分 类 号：TU443[建筑科学—岩土工程]