石灰岩孔道试样孔内卸压条件下破坏特征的研究

发布时间：2018-03-05 19:59

本文选题：岩石力学　切入点：孔道试样　出处：《岩石力学与工程学报》2017年06期 　论文类型：期刊论文

【摘要】：为了研究复杂应力环境下岩体工程开挖的影响,设计内压加卸载试验装置,利用内径20 mm、外径49.84 mm的厚壁圆筒石灰岩试样,在RMT 150C岩石力学试验系统进行不同内压条件下的加卸载试验,重点分析了孔内卸压条件下试样的破坏形式产生机制。结果表明:(1)固定孔压加载时,由于试样孔道内外存在应力差,不能进入延性变形阶段,高围压时有孔压试样的强度明显高于无孔压试样的强度;(2)孔压卸载对试样造成的损伤较大,卸载孔压后重新加载的试样,其强度低于常规三轴压缩时的孔道试样;卸载破坏时试样内外压差越大,其强度越小,表明围岩发生破坏的根源在于巷道开挖卸载后引起应力差的增加;(3)固定孔压时,试样多呈现单一的剪切面滑移破坏,而卸载孔压时试样破坏形式都为张拉破坏或者压拉组合破坏,应力路径对孔道试样破坏形式影响较大。研究结果为揭示深埋巷道围岩破坏失稳现象的产生机制提供参考。
[Abstract]:In order to study the influence of rock engineering excavation under complex stress environment, an internal pressure loading and unloading test device was designed. The thick-walled cylinder limestone samples with internal diameter of 20 mm and external diameter of 49.84 mm were used. The loading and unloading tests under different internal pressure conditions were carried out in the RMT 150C rock mechanics test system. The failure mechanism of specimens under the condition of internal pressure relief was emphatically analyzed. The results show that: 1) when the fixed pore pressure is loaded, Because of the stress difference inside and outside the pore channel of the specimen, it can not enter the stage of ductile deformation. The strength of the specimen with pore pressure at high confining pressure is obviously higher than that of the specimen without pore pressure, and the damage caused by the unloading of pore pressure is greater than that of the specimen without pore pressure. The strength of the specimen reloaded after unloading pore pressure is lower than that of the specimen under conventional triaxial compression, and the greater the pressure difference between the specimen and the specimen under unloading failure is, the smaller the strength is. The results show that the root of the failure of surrounding rock is the increase of stress difference caused by excavation and unloading of roadway. When the pore pressure is fixed, the specimen usually presents a single slip failure on the shear plane. However, the failure forms of specimens under unloading pore pressure are tensile failure or combined compression failure, and the stress path has a great influence on the failure form of tunnel specimen. The results provide a reference for revealing the mechanism of failure and instability of deep buried roadway surrounding rock.
【作者单位】：湖南科技大学南方煤矿瓦斯与顶板灾害预防控制安全生产重点实验室;湖南科技大学煤矿安全开采技术湖南省重点实验室;中南大学资源与安全工程学院;湖南科技大学资源环境与安全工程学院;
【基金】：国家自然科学基金资助项目(51474103) 国家重点研发计划(2016YFC0600706) 湖南省自然科学基金资助项目(2015JJ2070)~~
【分类号】：TU45

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