摘要
以改造废弃巷道作为压缩空气储能系统,研究改造后巷道混凝土衬砌在循环拉应力作用下的稳定性o利用MTS-816岩石伺服试验系统对预制切口混凝土梁在循环载荷作用下的断裂特征进行了研究。首先,进行了单调加载条件下的三点弯曲试验,获得平均破坏载荷和平均断裂韧度。然后,进行了循环载荷试验,并计算断裂韧度。研究表明:当上限载荷比为0.8,循环载荷作用下的峰值COD(裂纹开口位移)变化可分为减速扩展阶段、等速扩展阶段和加速扩展阶段;当上限载荷比小于0.8,循环载荷作用下的峰值COD经过减速扩展阶段和等速扩展阶段的发展后,进入停滞扩展阶段,COD不再增加,裂纹不再扩展;混凝土断裂韧度的衰减与循环载荷的上限载荷有关,当上限载荷比从0.6提高至0.8时,断裂韧度衰率从0.8%增加至12.7%,断裂韧度衰减显著,反之则不超过0.8%,基本无衰减。
Taking on the retrofit abandoned laneway as compressed air energy storage system,we study the stability of its concrete lining under cyclic tensile stress.MTS-816 rock servo experimental system was introduced to cyclic three-point-bending test of notched concrete beam.Firstly,the average failure load and the average fracture toughness were obtained by the three point bending test under monotonic loading.Then,cyclic loading tests were carried out and fracture toughness was calculated.The test results show that:when the upper load ratio is 0.8,the peak COD(crack open displacement)curve can be divided into three stages,i.e.decelerated stage,stable stage and accumulation stage;when upper load ratio is below 0.8,the peak COD curve will get into stagnation stage after stable stage,COD no longer increases,crack no longer expands;the attenuation of fracture toughness of concrete is related to the upper limit of cyclic load.When the upper limit load ratio increases from 0.6 to 0.8,the fracture toughness decline rate increases from 0.8%to 12.7%,and the fracture toughness decreases significantly;otherwise,it does not exceed 0.8%,and there is basically no attenuation.
作者
薛欣然
刘辉
XUE Xinran;LIU Hui(School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221000,China;Slate Key Laboratory for Geo-mechanics&Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221000,China)
出处
《煤矿安全》
CAS
北大核心
2019年第11期72-75,共4页
Safety in Coal Mines
关键词
压缩空气储能系统
三点弯曲试验
循环载荷
断裂韧度
裂纹开口位移
混凝土
compressed air energy storage(CAES)
three-point-bending test
cyclic loading
fracture toughness
crack open displacement(COD)
concrete
