采空区破碎砂岩承压变形特性试验研究  

Experimental study on pressure-bearing deformation characteristics of crushed sandstone in gob

作　　者：孙亚楠[1,2] 张培森 颜伟[1,2] 闫奋前 吴俊达[1,2] SUN Yanan;ZHANG Peisen;YAN Wei;YAN Fenqian;WU Junda(State Key Laboratory of Mining Disaster Prevention and Control,Shandong University of Science and Technology,Qingdao 266590,China;Mining Engineering National Experimental Teaching Demonstration Center,Qingdao 266590,China)

机构地区：[1]山东科技大学矿山灾害预防控制省部共建国家重点实验室培育基地,山东青岛266590 [2]矿业工程国家级实验教学示范中心,山东青岛266590

出　　处：《煤炭科学技术》2019年第12期56-61,共6页Coal Science and Technology

基　　金：国家重点研发计划资助项目(2018YFC0604702);国家自然科学基金资助项目(51509149,51379119,51774199);山东省重点研发计划资助项目(2018GSF120009)

摘　　要：为研究采空区直接顶垮落后碎石在各种状态下的承载能力,利用破碎岩石变形-渗流试验系统进行了破碎砂岩的压缩变形试验,分析了粒径大小、级配组合、饱水状态、加载方式4种因素变化对破碎砂岩变形特性的影响。研究结果表明:破碎砂岩的应力-应变关系与碎石粒径大小、级配组合、饱水状态及加载方式密切相关;不同粒径组碎石其应力-应变关系均可用指数函数表示,且相同应力作用下大粒径组碎石应变增加较快;随着级配指数n的增加,级配碎石组中大粒径碎石含量增多,试验应力加载终点应变相应增大;被水软化过的同一级配碎石在相同应力作用下其应变增量明显大于干燥状态下碎石应变增量,饱水作用使得破碎砂岩的承载能力降低了近14%;循环加卸载作用下碎石应力-应变关系仍可用指数函数表示,且循环加卸载作用下碎石应变终值约为连续加载碎石应变终值的1.25倍。研究结果可为采空区地表沉降与围岩变形控制提供了理论指导。In order to study the bearing capacity of the underlying gravel in the gob under various conditions,the fracture deformation test of the fractured sandstone was carried out by using the fractured rock deformation-seepage testsystem.The effects of particle size,gradation combination,saturated state and loading mode on the deformation characteristics of fractured sandstone were analyzed.Research results indicate that the stress-strain relationship of fractured sandstone is closely related to particle size,gradation combination,saturated state and loading mode,and the stress-strain relationship of different particle size can be expressed by exponential function.Under the action of stress,the strain of the large-size group of gravel increases rapidly;with the increase of the gradation index n,the content of large-size gravel in the graded gravel group increases,and the strain value at the end of the test stress loading increases accordingly;the strain increment of the same grade of gravel under the same stress is obviously greater than that of the gravel strain in the dry state.The saturated water load reduces the bearing capacity of the fractured sandstone by nearly 14%;under cyclic loading and unloading the gravel stress-strain relationship can still be expressed by an exponential function,and the final value of the gravel strain under cyclic loading and unloading is about 1.25 times the final value of the continuously loaded crushed stone.The study provides theoretical guidance for surface settlement and surrounding rock deformation control in gob.

关 键 词：岩石力学 饱水破碎岩石 承压变形 循环加卸载 

分 类 号：TD315[矿业工程—矿井建设]