FLAC^(3D)中锚杆破断失效的实现及应用

Implementation of bolt broken failure in FLAC^(3D) and its application

为解决FLAC^(3D)中CABLE单元无法实现锚杆(索)破断失效的问题,提出锚杆(索)破断判据U(i)≥U_(max)(i),在此基础上建立CABLE单元杆体修正力学模型,修正模型增加了破断失效功能,并采用Fish语言编程,将修正模型嵌入到FLAC^(3D)主程序中,实现锚杆破断失效的"单元化",由局部到整体自发实现锚杆的宏观破断效果。进行锚杆杆体拉伸实验和锚喷支护效果对比的算例分析,结果表明:(1)修正模型锚杆杆体拉伸荷载–位移曲线呈现出第三阶段破断失效的特性,符合杆体实际力学行为,达到了定量破断的预期效果,且响应灵敏;(2)地应力超过一定值后,采用修正模型的支护方案中锚杆、锚索出现了破断,且呈现出的力学行为符合锚杆(索)破断失效力学机制,提高了工程模拟的准确度和精度;(3)破断实现方法扩展了FLAC^(3D)的应用范围,增强了模拟能力。同时分析指出了实现方法可达到的有益效果、存在的局限性及下一步研究方向。

In order to solve the problem that CABLE element in FLAC^3D cannot be broken failure,a broken criterion U（i）≥U_（max）（i） was proposed and a modified mechanical model of CABLE element was established. The broken failure function was added to the modified model and the new model was embedded in the main program of FLAC^3D with the FISH language programming. The broken failure of bolt was realized at the single element level,and the macroscopic broken was finally achieved from parts to whole spontaneously. The tensile tests of bolt bar and the roadway bolt-shotcrete support tests were carried out. The load-displacement curve of the cable bar using the modified model presented the broken failure characteristic,which was in accordance with the actual mechanical behavior of bolt rod,and the quantitative broken effect was achieved and the response was sensitive. When the ground stress exceeded a certain value,the modified bolts and anchor cables broke in the surrounding rock,the mechanical behavior conformed to the broken failure mechanism of bolt or cable anchor in the practical engineering. The simulation accuracy was improved. The application range of FLAC^3D was expanded,and the simulation capability was enhanced.