Thermal and mechanical coupling-induced meso-scale mechanism on failurestrength and AE law of granite

 Xue Dongjie●Zhou Hongwei●Hu Ben●Ren Weiguang

Abstract

Based on SEM,a series of experiments on granite meso-scale mechanics were carried out. As a comparison,an accurate numerical model was established using multi-threshold segmentation method to distinguish different materials in the granite samples. A further study had been made to focus on thermal and mechanical coupling-induced mesoscale behavior including failure strength and acoustic emission ( i. e. AE) under uni-axial tension. Three coupling paths were designed for heating and loading axial tension. The first path is to heat the samples at a predetermined temperature,then increase the loading until the destruction of samples. By contrary,the second path is to load the samples to a predetermined value,then heat the samples until their failure. Considering the coupled effect,the third path is to pressure and heat the samples alternately. The results show that the different laws of acoustic emission can be summarized into three types corresponding to the different range of temperature and strength. There is an exponentially decreasing trend between the strength and temperature in different paths. The failure strength is a single-valued function of temperature. In the simulation model,the acoustic emission characteristics under different load paths depend mainly on the coupled value of temperature and stress.

热力耦合作用花岗岩细观破坏强度及声发射规律

薛东杰,周宏伟,胡 本,任伟光

摘 要

利用 SEM 全数字液压高温疲劳实验系统开展花岗岩细观力学实验,采用多阈值分割法区分材料组成并构建细观数值模型,开展单轴拉伸条件下花岗岩热力耦合作用下的强度破坏特征与声发射规律研究。 设计 3 种升温加载路径,路径Ⅰ:先升温到预定温度点后位移加载至破坏;路径Ⅱ:先加载到预定载荷点后升温至破坏;路径Ⅲ:以固定的载荷增量温度增量交替升温加载直至试件破坏。 详细探讨了 3 种不同路径下声发射规律,在不同的温度强度区间,可分为 3 种类型。 3 种不同路径均表现为花岗岩的强度随温度的升高呈指数型衰减趋势,强度是温度的单值函数。 细观模型中不同温度-载荷路径下的声发射特性主要取决于破坏时的温度和强度。

引用格式：

Xue DJ, Zhou Hw, Hu B, REN WG. Thermal and mechanical coupling-induced meso-mechanism on failure strength and AE law of Granite [J]. Journal of China Coal Society, 2015, 40(09): 2065-2074. 薛东杰, 周宏伟, 胡本,任伟光. 热力耦合作用花岗岩细观破坏强度及声发射规律[J]. 煤炭学报, 2015, 40(09): 2065-2074.

DOI：10.13225/j.cnki.jccs.2014.1497

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