岩土力学
巖土力學
암토역학
Rock and Soil Mechanics
2015年
11期
3085-3093
,共9页
劈裂石灰岩岩芯%摩擦滑动特性%摩擦强度%时间依赖性%滑动稳定性%渗透率
劈裂石灰巖巖芯%摩抆滑動特性%摩抆彊度%時間依賴性%滑動穩定性%滲透率
벽렬석회암암심%마찰활동특성%마찰강도%시간의뢰성%활동은정성%삼투솔
split limestone core%frictional sliding behavior%frictional strength%time-dependent behavior%sliding stability%permeability
为研究石灰岩裂隙的摩擦滑动特性,搭建了三轴试验系统,进行了劈裂石灰岩岩芯在湿润和干燥条件下的滑动-控制-滑动试验、速度步长试验和渗透试验。通过滑动-控制-滑动试验和速度步长试验分别研究了石灰岩裂隙摩擦强度的时间依赖性和滑动稳定性,并进一步分析了水对裂隙摩擦强度特性的影响,同时还通过渗透试验观察了裂隙渗透率在滑动过程中的变化。滑动-控制-滑动试验表明:裂隙的摩擦强度具有时间和应力依赖性,裂隙摩擦强度在控制时间内的下降量及重新滑动后的愈合量均与控制时长成正比,而与有效压应力成反比;此外,摩擦强度特性还明显受到水的影响。速度步长试验则表明:石灰岩裂隙摩擦强度随滑动速度的增加而增大,呈现速度强化特性。最后通过不同有效正应力下(介于1-3 MPa之间)的渗透试验发现:裂隙的渗透率不仅随有效应力的增加而急剧下降,而且在各级正应力下亦随滑动而逐渐减小。
為研究石灰巖裂隙的摩抆滑動特性,搭建瞭三軸試驗繫統,進行瞭劈裂石灰巖巖芯在濕潤和榦燥條件下的滑動-控製-滑動試驗、速度步長試驗和滲透試驗。通過滑動-控製-滑動試驗和速度步長試驗分彆研究瞭石灰巖裂隙摩抆彊度的時間依賴性和滑動穩定性,併進一步分析瞭水對裂隙摩抆彊度特性的影響,同時還通過滲透試驗觀察瞭裂隙滲透率在滑動過程中的變化。滑動-控製-滑動試驗錶明:裂隙的摩抆彊度具有時間和應力依賴性,裂隙摩抆彊度在控製時間內的下降量及重新滑動後的愈閤量均與控製時長成正比,而與有效壓應力成反比;此外,摩抆彊度特性還明顯受到水的影響。速度步長試驗則錶明:石灰巖裂隙摩抆彊度隨滑動速度的增加而增大,呈現速度彊化特性。最後通過不同有效正應力下(介于1-3 MPa之間)的滲透試驗髮現:裂隙的滲透率不僅隨有效應力的增加而急劇下降,而且在各級正應力下亦隨滑動而逐漸減小。
위연구석회암렬극적마찰활동특성,탑건료삼축시험계통,진행료벽렬석회암암심재습윤화간조조건하적활동-공제-활동시험、속도보장시험화삼투시험。통과활동-공제-활동시험화속도보장시험분별연구료석회암렬극마찰강도적시간의뢰성화활동은정성,병진일보분석료수대렬극마찰강도특성적영향,동시환통과삼투시험관찰료렬극삼투솔재활동과정중적변화。활동-공제-활동시험표명:렬극적마찰강도구유시간화응력의뢰성,렬극마찰강도재공제시간내적하강량급중신활동후적유합량균여공제시장성정비,이여유효압응력성반비;차외,마찰강도특성환명현수도수적영향。속도보장시험칙표명:석회암렬극마찰강도수활동속도적증가이증대,정현속도강화특성。최후통과불동유효정응력하(개우1-3 MPa지간)적삼투시험발현:렬극적삼투솔불부수유효응력적증가이급극하강,이차재각급정응력하역수활동이축점감소。
In this paper, a triaxial experimental apparatus is developed to investigate the frictional sliding behavior of fissures in limestone. Slide-hold-slide (SHS) tests, velocity stepping (VS) tests and permeability tests are conducted on the limestone core samples under both dry and wet conditions. Time-dependence and sliding stability are firstly studied through SHS tests and VS tests, respectively, and then the effect of water on the frictional behavior of fissures is further analyzed. Meanwhile, the permeability of fissures is measured during the sliding process in permeability tests. SHS tests show that frictional strength of fissures exhibits significant time-and stress-dependent behavior. The decreasing magnitude of frictional strength at the controlled time and the healing magnitude after re-sliding are proportional to the controlled time intervals, but inversely proportional to the effective confining stress. In addition, the frictional behavior is obviously influenced by water. However, VS tests demonstrate that frictional strength of limestone increases with increasing sliding velocities, which indicates the velocity-strengthening behavior. Finally, it can be seen from a series of permeability tests under varied effective normal stresses from 1 to 3 MPa is carried out, the permeability declines sharply with the increase of effective confining stress, and even decreases gradually with sliding process at each level of effective confining stress.