高温条件下炮孔围岩爆炸冲击损伤特性研究  

Study on damage characteristics of blasthole surrounding rock under high temperature

作　　者：黄江北 严鹏[1,2] 卢文波[1,2] 陈明[1,2] 王高辉[1,2] HUANG Jiangbei;YAN Peng;LU Wenbo;CHEN Ming;WANG Gaohui(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan,Hubei 430072,China;Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of Ministry of Education,Wuhan University,Wuhan,Hubei 430072,China)

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072 [2]武汉大学水工岩石力学教育部重点实验室,湖北武汉430072

出　　处：《岩石力学与工程学报》2020年第11期2244-2253,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51779192);国家自然科学基金–雅砻江联合基金资助项目(U1765109);国家“十三五”重点专项课题资助项目(2016YFC0401802)。

摘　　要：高温条件下脆性岩石的冲击损伤总体上反映了其开裂特性,对干热岩能源具有实际工程意义。通过对不同温度下花岗岩的霍普金森压杆破坏过程的模拟,得到能反映温度作用效应的HJC本构模型参数,研究不同温度条件下的花岗岩炮孔围岩的爆炸冲击损伤和开裂特性。结果表明,在爆炸冲击荷载作用下,炮孔周围的粉碎区对温度变化不敏感,而爆炸裂隙区在100℃温度时较常温显著增大,100℃~500℃范围则变化不大;其次,在保持爆炸冲击荷载峰值1 500 MPa不变的条件下,爆炸荷载加载速率增大,对常温围岩裂隙区有显著影响,而对高温围岩影响不明显;当爆炸荷载冲量增大或作用时间延长时,裂隙区范围显著增加,100℃~500℃范围高温围岩增加幅度更大。因此,在干热岩开采井下致裂过程中,为减小孔壁粉碎区、增大裂隙区范围,建议采用低爆速炸药,以控制炮孔周围粉碎区的范围,同时需增加装药量以延长荷载作用时间,从而增大裂隙区范围,达到更好的致裂效果。高地温虽然会在一定程度上影响炸药的冲击性能,但更有利于爆炸冲击致裂。The shock damage of brittle rock under high temperature generally reflects its cracking characteristics,which is of significance in practical engineering of dry hot rock energy resources. In this paper,the parameters of the HJC constitutive model that can reflect the temperature effect are obtained by simulating the granite failure process with Hopkinson pressure bar under different temperatures. For a single blasthole,the granite damage and cracking characteristics under different temperatures are studied. The results indicate that the crush area around the blasthole is not sensitive to temperature changes under the blasting loading while the crack area increases substantially under 100 ℃ temperature but changes little between 100 ℃ and 500 ℃. Then keeping the blasting load peak(1 500 MPa) unchanged,the increase of loading rate has a great influence on the crack area at room temperature but a negligible influence at high temperature. And the increase of explosion load impulse or the action time can result in the expansion of crack area obviously,especially at a high temperature between 100 ℃ and 500 ℃. Therefore,to reduce the crush area and increase the crack area of surrounding rock during the dry hot rock cracking process,the low-detonation-velocity explosive is suggested to use for controlling the crush area. And raising the charge weight correspondingly to increase the load action time can increase the crack area for better cracking effect. Although the high ground temperature can affect the impact property,cracking effect induced by explosion will be enhanced.

关 键 词：岩石力学 干热岩 高地温 围岩损伤 爆炸冲击荷载 

分 类 号：TU45[建筑科学—岩土工程]