基于大型三轴试验的蚀变花岗岩力学行为及浸水湿化研究  

Mechanical behaviors and wetting-induced deformation of metamorphic granite based on large-scale triaxial test

作　　者：茆大炜 杜少华 李地元[3] 石北啸[4] 阮波[5] MAO Dawei;DU Shaohua;LI Diyuan;SHI Beixiao;RUAN Bo(PowerChina Zhongnan Engineering Corporation Limitedy Changsha,Hunan 410014,China;Hunan Provincial Laboratory of Key Technology on Hydropower Development,Changsha y Hunan 410014,China;School of Resources and Safety Engineerings Central South University,Changsha,Hunan 410086,China;Geotechnical Engineering Department of Nanjing Hydraulic Research Institute,Nanjing,Jiangsu 210029,China;School of Civil Engineering,Central South University,Changsha,Hunan 410075,China)

机构地区：[1]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014 [2]水能资源利用关键技术湖南省重点实验室,湖南长沙410014 [3]中南大学资源与安全工程学院,湖南长沙410083 [4]南京水利科学研究院岩土工程研究所,江苏南京210029 [5]中南大学土木工程学院,湖南长沙410075

出　　处：《岩石力学与工程学报》2020年第9期1819-1831,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点研发计划(2018YFC1508502);湖南省自然科学基金项目(2017JJ2296,2019JJ20028)。

摘　　要：位于断层破碎带且富含地下水的工程围岩软弱、破碎,存在严重的湿化塌陷隐患,工程维护面临诸多技术难题。以河南五岳蓄水电站断层破碎带蚀变花岗岩为对象,通过现场采样及重塑配比制样,运用大型三轴剪切仪研究了符合现场水力环境(含水率、围压及应力水平)下岩体的力学行为及发生浸水湿化后的变形特性。力学强度试验结果表明:不同含水率试样的峰值强度、峰值应变均随围压增大而升高,干燥试样的峰值强度平均比自然、饱和状态下高出22.90%和27.33%,而后两者之间平均差值仅为3.61%;含水率的改变显著影响试样的峰值应变,围压一定时,自然含水试样的峰值应变最大,干燥的却最小。湿化试验结果表明:湿化应变增量指标(△ε1s,△εvs及△γs)均受到应力水平、围岩变化的显著影响,相对于围压,应力水平对各指标作用更为敏感,当应力水平逐级增加1倍时,3个指标分别平均增大2.59,1.41,3.17倍。对比蚀变花岗岩浸水湿化前后的强度和变形情况,浸水湿化不仅减弱其本身力学强度,且加大其体变量。构建了反应此类岩土体湿化应变增量的数学模型,可用作现场围岩湿化变形安全评估及开展有限元数值分析。The surrounding rock mass of underground engineering containing abundant groundwater in fault fracture zones is weak and broken,and is susceptible to severe collapse caused by humidification,thus resulting in many technical problems for engineering maintenance.Taking metamorphic granite of the fault fracture zone at Wuyue Pumped Storage Power Station,Henan province of China,as the object,large-scale tri-axial tests were conducted to investigate the mechanical behavior and wetting-induced deformation of rock masses under the hydraulic environment including moisture content,confining pressure and stress level.The test results reveal that,as the confining pressure increase,the peak strength and peak strain of specimens increase under different water states,and that the peak strength under dry state is respectively 22.90%and 27.33%averagely higher than that under natural and saturated states while the difference between the latter two is only 3.61%.It is worthwhile mentioned that the peak strain is the largest under natural state and the smallest under dry state,indicating that the peak strain is markedly influenced by the moisture content.It is also shown that the wetting-induced strain increment (i.e.axial strain increment ■,volume strain increment-■ and shear strain increment ■) is significantly affected by the stress level and confining pressure,and that effect the stress level on these three indicators is more sensitive compared to the confining pressure.In particular,1 time increment of the stress level will lead to the improvement of the three indicators by an average of 2.59,1.41 and 3.17 times,respectively.Comparison of the strength and deformation of granite samples before and after wetting shows that wetting deformation not only weakens the strength properties of the rock mass but also increases the volumetric deformation.The proposed calculation model upon wetting-induced deformation obtained through the experimental results was recommended as the reference for safety assessment of wetting-induced d

关 键 词：岩石力学 断层破碎带 大三轴试验 蚀变花岗岩 力学行为 湿化变形 

分 类 号：TU45[建筑科学—岩土工程]