2010.8溷凝土随机损伤力学(教育部暑期学校讲座,长沙)

第50卷第2期中南大学学报(自然科学版) V ol.50No.2 2019年2月Journal of Central South University (Science and Technology)Feb. 2019 DOI: 10.11817/j.issn.1672−7207.2019.02.022冲击荷载作用下岩石压动态和拉动态损伤模型谢福君，张家生，陈俊桦(中南大学土木工程学院，湖南长沙，410075)摘要：根据经典岩石冲击动态损伤模型和统计损伤力学理论，提出冲击荷载加载条件下的岩石压、拉统计损伤本构模型和冲击损伤判据模型。

在该损伤模型中，将损伤演化关系分为体积压缩损伤和体积拉伸损伤2种。

应用提出的损伤模型和经典动态拉伸损伤模型分别进行爆破损伤数值模拟，并将数值计算结果和现场实测结果进行对比。

研究结果表明：与炮孔轴向相比，炮孔径向是爆破破裂延伸的主方向；沿炮孔径向主要发生拉伸破裂，孔底下方主要发生压缩破裂；与基于经典冲击动态拉伸损伤模型的数值计算结果相比，根据损伤模型得到的爆破破裂范围特别是孔底正下方破裂深度与实测值相差不大且最接近实测值，表明所提出的损伤模型是合理的，具有实用性。

关键词：岩石；动力损伤作用；压缩; 拉伸；爆破数值模拟中图分类号：TU45；TD235 文献标志码：A 文章编号：1672−7207(2019)02−0420−08 Dynamic damage model of rock under impact loads ofcompression and tensionXIE Fujun, ZHANG Jiasheng, CHEN Junhua(School of Civil Engineering, Central South University, Changsha 410075, China)Abstract: An impact-induced damage constitutive model based on classical impact-induced constitutive models and statistic damage mechanics was presented. In the model, damage evolutions were considered to be caused by volume compression and volume tension, respectively, and the presented model considered that compression strength of rock was much bigger than its tension strength. Numerical simulation of blasting was conducted according to the presented model.Results of blasting-induced fracture zone among the numerical simulation based on presented model and those of the blasting numerical simulation based on current tension damage model and actual measurement in field were comparied.The results show that the cardinal extension direction of fracture zone is the radial direction of blast hole rather than the axial direction of blast hole. The tension-induced fracture mainly appears along the radial direction while the compression-induced fracture mainly appears along the axial direction. The blasting-induced fracture zone obtained from the numerical simulation based on the presented model, especially the fracture depth under blast hole, is much closer to the actual measurement result than that obtained from the numerical simulation based on the current dynamic tension damage models. There is little difference between the numerical simulation results based on the presented model and actual measurement, indicating that the presented model is reasonable and useful.Key words: rock; dynamic damage; compression; tension; numerical simulation of blasting在冲击荷载作用下，岩石动态本构关系是爆破工程、地下防护工程等领域的研究热点。

第51卷第12期2020年12月中南大学学报(自然科学版)Journal of Central South University (Science and Technology)V ol.51No.12Dec.2020干湿循环作用下基于Laplace 分布的裂土应变硬化损伤模型周峙1，2，张家铭1，2，宁伏龙1，2，罗易1，2(1.中国地质大学(武汉)工程学院，湖北武汉，430074；2.地质探测与评估教育部重点实验室，湖北武汉，430074)摘要：为了建立干湿循环作用下裂土应变硬化损伤模型，提出裂土微元强度服从Laplace 分布的假定，同时考虑初始损伤门槛影响，引入干湿循环损伤变量和荷载作用损伤变量，分别描述裂土干湿循环开裂和应力水平作用下损伤演化规律。

基于不同干湿循环阶段裂土的固结不排水三轴剪切试验，探究围压对不同干湿循环开裂损伤的影响；利用线性拟合确定应变硬化损伤模型参数，探讨围压和干湿循环次数对初始损伤应力门槛值的影响，并对比验证不同干湿循环次数与应力水平作用下的试验结果。

研究结果表明：干湿循环对裂土平均微元强度影响显著，5次循环后，微元平均强度降幅显著，相比初始状态降低39.7%~78.5%；反映平均微元强度与弹性模量的Laplace 分布参数m 0和T 0均与围压呈正相关；围压提高了初始应力损伤门槛值，降低了干湿循环作用造成的损伤，相比初始状态试样，5，8和12次干湿循环后试样的初始损伤应力门槛值分别降低37.77%，45.67%和57.43%。

建立的基于Laplace 分布的损伤本构模型能充分反映干湿循环作用后裂土受荷时的应变硬化特征，并可模拟裂土在干湿循环和围压共同作用下的全应力−应变曲线，其模型参数易获取，且具有明确的物理意义；干湿循环次数愈多，围压愈高，模型与土体应力−应变试验曲线吻合程度越高。

关键词：裂土；干湿循环；Laplace 分布；应变硬化；统计损伤模型中图分类号：TU45文献标志码：A开放科学(资源服务)标识码(OSID)文章编号：1672-7207（2020）12-3484-09Strain hardening damage model of cracked soil during dry-wetcirculation based on Laplace distributionZHOU Zhi 1，2,ZHANG Jiaming 1，2,NING Fulong 1，2,LUO Yi 1，2(1.School of Engineering,China University of Geosciences,Wuhan 430074,China;2.Key Laboratory of Geological Survey and Evaluation of Ministry of Education,Wuhan 430074,China)Abstract:In order to establish the strain hardening damage model of cracked soil during the drying-wetting cycles,the hypothesis that the strength of cracked soil obeys Laplace distribution was proposed.Considering the influence of initial damage threshold,the damage evolution law of cracked soil during drying-wetting cycles andDOI:10.11817/j.issn.1672-7207.2020.12.022收稿日期：2020−02−21；修回日期：2020−05−12基金项目(Foundation item)：地质探测与评估教育部重点实验室主任基金和中央高校基本科研业务费(GLAB2019ZR05)；国家自然科学基金资助项目(41372311)；安徽省交通运输厅科技进步计划项目(2018030)(Project(GLAB2019ZR05)supported by the Opening Fund of Key Laboratory of Geological Survey and Evaluation of Ministry of Education and the Fundamental Research Funds for the Central Universities;Project(41372311)supported by the National Science Foundation of China;Project(2018030)supported by the Science and Technology Plan of Anhui Provincial Department of Transport)通信作者：张家铭，博士，副教授，从事特殊性岩土工程防治研究；E-mail ：*************第12期周峙，等：干湿循环作用下基于Laplace分布的裂土应变硬化损伤模型at different stress levels was described by introducing the damage variable of drying-wetting cycles and load.Based on the triaxial consolidation undrained shear test(CU)of cracked soil during different drying-wetting cycles, the influence of confining pressure on cracking damage during drying-wetting cycles was investigated.The parameters of damage model were determined by linear fitting,the effects of confining pressure and drying-wetting cycles on the threshold value of initial damage stress were discussed,and the results were compared with those during different dry wet cycles and at different stress levels.The results show that the drying-wetting cycle has a significant effect on the average micro element strength.After five cycles,the average micro element strength decreases significantly,which is39.7%−78.5%lower than that of the initial state.The parameters of theLaplace distribution,m0and T,which reflect the mean strength and elastic modulus of the microelements,arelinearly and positively correlated with confining pressure.Confining pressure can improve the initial damage threshold and reduce the damage caused by the drying-wetting pared with the initial state of samples, the initial damage stress threshold of samples after5,8and12cycles reduces by37.77%,45.67%,and57.43%, respectively.The damage constitutive model based on Laplace distribution can fully reflect the strain hardening characteristics of cracked soil under load after dry and wet cycles,and can simulate the stress−strain curve of cracked soil under the combined action of dry and wet cycles and confining pressures.The model parameters are easy to obtain and have clear physical significance.The more the number of drying-wetting cycles,the higher the confining pressure,the more the model is consistent with the stress-strain test curve of soil.Key words:cracked soil;wet-dry circulation;Laplace distribution;strain hardening;statistical damage model裂土是一种弱膨胀和强收缩的黏性土，在安徽沿江垄岗地区广泛发育。