基于表观弹性模量变化规律的类岩石材料滞回环形态分类及预测研究

(1.三峡大学 湖北省地质灾害防治工程技术中心,湖北 宜昌443002; 2.三峡大学 三峡库区地质灾害教育部重点实验室,湖北 宜昌 443002; 3.北京市勘察设计研究院有限公司,北京 100038)

循环加卸载; 表观弹性模量; 滞回环形态分类; 滞回环预测

Study on classifications and prediction of rock hysteresis loop based on apparent elastic modulus change law
LIU Jie1,2, XIE Xiaokang 1,2,GAO Sufang3, YANG Yunan1,2,LAN Jun1,2, WANG Fei 1,2

(1. Engineering Technology Center for Geological Disaster Prevention of Hubei Province, China Three Gorges University,Hubei Yichang 443002,China; 2.Key Laboratory of Geological azards on Three Gorges Reservoir Area, Ministry of Education, China Three Gorges University, Hubei Yichang 443002,China; 3.BGI Engineering Consultants Ltd., Beijing 100038,China)

cyclic loading and unloading; apparent elastic modulus; classification of hysteresis loops; prediction of hysteresis loops

DOI: 10.15986-j.1006-7930.2020.04.004

备注

基于RMT-150C岩石力学试验系统,研究循环载荷下砂岩的力学响应,基于提出的E(t)=af(t)+b关系式,根据加载段表观弹性模量的变化规律,将非瞬时加载的滞回环形态分为持续增大、持续减小和先增后减三种形态.指出表观弹性模量的变化是由试样内部微裂隙、微孔洞的压密系数a1和滑移展开数a2两种因素共同作用的结果,并结合公式中a=a1+a2值的正负变化分析三种形态滞回环产生机理.根据公式中a值和b值随峰值、加载频率和围压变化存在的规律,可由两个及以上已知滞回环完成对其它任意滞回环的预测,并给出了详细的计算公式及流程,同时对每种不同滞回环的实例进行机理分析.试验证明,本预测方法适用于不同峰值(64~112 kN)、不同加载速率(0.2~20 kN/s)与围压(0~20 MPa)条件下三种不同形态滞回环.

Based on the RMT-150C rock mechanics test system, the mechanical response of sandstone samples under cyclic loading was studied. Based on the proposed E(t)=af(t)+b relation, and according to the change law of apparent elastic modulus of the loading section, the hysteretic loop forms under non-instantaneous loading were divided into three forms: continuous increased, continuously decreased, and first increase and then decrease. It is pointed out that the change of the apparent modulus of elasticity is the result of the joint action of the micro-crack inside the sample, the compression density coefficient a1 of the micro-hole and the slip expansion number a2. In combination with the positive and negative change of a=a1+a2 value in the formula, the mechanism of the three forms of hysteresis loop is analyzed. According to the change law of A value and B value in the formula with the change of peak value, loading frequency and confining pressure, two or more known hysteresis loops can be used to predict any other hysteresis loops, and the detailed calculation formula and process are given. Meanwhile, the mechanism analysis of each different hysteresis loop is carried out. The test results show that the prediction method is applicable to three types of hysteresis loops with different peak values(64~112 kN), loading rates(0.2~20 kN/s)and confining pressures(0~20 MPa).