小孔径圆锥式孔底套芯应力解除法及试验研究  

Experimental study on the stress relief method of small-diameter compact conical-ended borehole overcoring technique

作　　者：赵善坤[1,2] 高桂云 王成虎 张宁博 刘一民[3] 侯正阳 刘香兰 ZHAO Shankun;GAO Guiyun;WANG Chenghu;ZHANG NingBo;LIU Yimin;HOU Zhengyang;LIU Xianglan(State Key Laboratory of Coal Mining and Clean Utilization,China Coal Research Institute,Beijing 100013;Mine Safety Technology Branch,China Coal Research Institute,Beijing 100013,China;National Institute of Natural Hazards, Ministry of Emergency Management of China,Beijing 100085, China;School of Engineering and Technology, China University of Geosciences(Beijing),Beijing 10083, China)

机构地区：[1]煤炭科学研究总院煤炭资源高效开采与洁净利用国家重点实验室,北京100013 [2]煤炭科学技术研究院有限公司安全分院,北京100013 [3]应急管理部国家自然灾害防治研究院,北京100085 [4]中国地质大学(北京)工程技术学院,北京100083

出　　处：《煤炭学报》2021年第S01期74-83,共10页Journal of China Coal Society

基　　金：国家自然基金资助项目(51874176);国家重点研究发展计划资助项目(2017YFC0804203);天地科技股份有限公司科技创新创业资金专项资助项目(2018-TD-QN004)。

摘　　要：为测试地下空间原地应力状态,研发了小孔径圆锥式孔底套芯地应力测试的孔底应变计,并开展了室内岩样的加载、卸载实验,验证了其测试结果可靠性。首先对孔底应变套芯应力测试方法的原理进行了简要介绍;然后针对煤矿巷道、隧道硐室等地下空间小孔径钻孔情况下的原地应力的快速测量要求,研发了直径为47 mm的小孔径圆锥式孔底应变计,并研制了配套的圆锥形钻头;最后开展了室内真三轴试验机加载和卸载实验,依据我国主要地区的应力比情况,设计了24种加载、卸载工况的实验,并对实验结果进行了分析处理。实验研究表明:研制的小孔径圆锥式孔底应变计可以方便的实现孔底安装与黏接;应用该应变计和多通道数字应变仪可以连续记录到加、卸载过程中的应变变化;依据记录的加载、卸载稳定阶段应变值,结合圆锥式孔底套芯应力解除测试方法的原理,采用MATLAB程序开展最小二乘求解可以反演得到施加的应力量值;通过室内12组不同应力比的加、卸载实验,得到24组应力反演结果,其相对误差绝对值均在50%以内,平均相对误差(绝对值)在18%以内,其中,S_(1)平均相对误差(绝对值)在17%左右,S_(2)平均相对误差(绝对值)在18%左右。通过实验研究,验证了该方法的可行性,为小孔径圆锥式孔底套芯地应力测试的应用与推广提供了理论及室内实验支撑。In order to measure the in-situ stress state in underground space,a small diameter conical-ended borehole strain meter for overcoring technique has been developed.The reliability of the test results of this strain meter was verified by laboratory loading and unloading experiments.First,the theory of compact conical-ended borehole overcoring technique was briefly presented.Then,a 47 mm-diameter conical-ended borehole strain meter was developed to measure the in-situ stress in underground space such as coal mine roadway and roadway chamber.A conical-ended bit was also designed and machined to drill the conical-ended hole for the tests.Results show that the developed small diameter conical-ended borehole strain meter can be easily installed and glued.The strain changes during loading and unloading process can be recorded by the small diameter conical-ended borehole strain meter combined with the multi-channel strain indicator.Based on the theory of conical-ended borehole overcoring technique,the stress can be inversed using the terminal strain recorded by the strain cell and the least square method based on MATLAB code.The 24 tests results of 12 stress ratio were conducted and used for stress inversion and verification of the strain meter.The error is within 50%with average error of 18%,in which the absolute value of mean error of S_(1) and S_(2) are 18%and 17%,respectively.The validity of this small-diameter compact conical-ended borehole overcoring technique was verified through those experiments,which could provide a theoretical foundation and experimental verification for the application and development of the small-diameter compact conical-ended borehole overcoring technique and fill the gap in this field in China.

关 键 词：套芯应力解除法 圆锥式孔底应变计 孔底应变 原地应力 三维应力测量 

分 类 号：TD322[矿业工程—矿井建设]