岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
4期
959-964,971
,共7页
邓华锋%原先凡%李建林%胡亚运%周美玲
鄧華鋒%原先凡%李建林%鬍亞運%週美玲
산화봉%원선범%리건림%호아운%주미령
软岩%抗压强度%破坏特征%半对数法
軟巖%抗壓彊度%破壞特徵%半對數法
연암%항압강도%파배특정%반대수법
soft rock%compressive strength%failure characteristics%semi-log method
软岩三轴加、卸载试验中的抗压强度参数取值是一个非常关键的问题,目前还没有比较确定的方法,通常根据经验或工程要求确定。基于此,结合一组砂质泥岩的三轴加、卸载试验进行了详细研究,试验结果表明:(1)当围压大于10 MPa时,不论是三轴加载试验还是卸载试验,砂质泥岩均表现出明显的应变硬化特性;(2)砂质泥岩在三轴压缩和三轴卸荷两种应力路径的力学响应差别明显,在卸荷条件下通常只存在一条完整的剪切破坏面,而压缩条件下岩样没有明显的控制破裂面,并且剪胀效应明显;(3)将半对数法引入到软岩三轴加、卸载试验数据分析中,可以比较方便地确定软岩三轴加、卸载试验的抗压强度;(4)基于三轴加、卸载试验过程中的应力、应变增量分析,将软岩变形破坏过程分为3个阶段:平滑阶段、规则跳跃阶段和急剧跳跃阶段,各阶段划分的意义明确,可以作为抗压强度确定时的重要参考,因此,在软岩三轴试验数据分析时,可以综合采用这两种方法。研究提出的抗压强度确定方法可操作性强,在其他软岩三轴试验数据分析中值得参考借鉴。
軟巖三軸加、卸載試驗中的抗壓彊度參數取值是一箇非常關鍵的問題,目前還沒有比較確定的方法,通常根據經驗或工程要求確定。基于此,結閤一組砂質泥巖的三軸加、卸載試驗進行瞭詳細研究,試驗結果錶明:(1)噹圍壓大于10 MPa時,不論是三軸加載試驗還是卸載試驗,砂質泥巖均錶現齣明顯的應變硬化特性;(2)砂質泥巖在三軸壓縮和三軸卸荷兩種應力路徑的力學響應差彆明顯,在卸荷條件下通常隻存在一條完整的剪切破壞麵,而壓縮條件下巖樣沒有明顯的控製破裂麵,併且剪脹效應明顯;(3)將半對數法引入到軟巖三軸加、卸載試驗數據分析中,可以比較方便地確定軟巖三軸加、卸載試驗的抗壓彊度;(4)基于三軸加、卸載試驗過程中的應力、應變增量分析,將軟巖變形破壞過程分為3箇階段:平滑階段、規則跳躍階段和急劇跳躍階段,各階段劃分的意義明確,可以作為抗壓彊度確定時的重要參攷,因此,在軟巖三軸試驗數據分析時,可以綜閤採用這兩種方法。研究提齣的抗壓彊度確定方法可操作性彊,在其他軟巖三軸試驗數據分析中值得參攷藉鑒。
연암삼축가、사재시험중적항압강도삼수취치시일개비상관건적문제,목전환몰유비교학정적방법,통상근거경험혹공정요구학정。기우차,결합일조사질니암적삼축가、사재시험진행료상세연구,시험결과표명:(1)당위압대우10 MPa시,불론시삼축가재시험환시사재시험,사질니암균표현출명현적응변경화특성;(2)사질니암재삼축압축화삼축사하량충응력로경적역학향응차별명현,재사하조건하통상지존재일조완정적전절파배면,이압축조건하암양몰유명현적공제파렬면,병차전창효응명현;(3)장반대수법인입도연암삼축가、사재시험수거분석중,가이비교방편지학정연암삼축가、사재시험적항압강도;(4)기우삼축가、사재시험과정중적응력、응변증량분석,장연암변형파배과정분위3개계단:평활계단、규칙도약계단화급극도약계단,각계단화분적의의명학,가이작위항압강도학정시적중요삼고,인차,재연암삼축시험수거분석시,가이종합채용저량충방법。연구제출적항압강도학정방법가조작성강,재기타연암삼축시험수거분석중치득삼고차감。
In triaxial loading and unloading tests of soft rock, the determination of compressive strength is a critical problem, which always tends to use empirical method,while less corresponding standards at present. Based on this, a set of triaxial loading and unloading tests of sandy mudstone were carried out and the experiment results show that:(1) Sandy mudstone samples always show obvious strain hardening characteristics in both triaxial loading and unloading tests when the confining pressure is more than 10 MPa. (2) The mechanical response differences of sandy mudstone under triaxial loading and unloading tests are obviously, the samples always have only one macro shear failure surface in triaxial unloading tests; while the samples have no obvious control fracture surface under the condition of triaxial loading, and the dilatancy effect is obvious. (3) The semi-log method was introduced into the data analysis of soft rock triaxial loading and unloading tests, which can determine the compressive strength more conveniently. (4) Based on the analysis of stress and strain increment in the process of triaxial loading and unloading tests, the deformation and failure process of soft rock can be divided into three stages:smooth stage, rule jump stage and sharp jump stage;the division has obvious physical significance, which can be used as an important reference for determining the compressive strength. Therefore, the two methods can be integrated used to determine the compressive strength of soft rock in triaxial loading and unloading tests. The methods for determining the compressive strength is very applicable, and can also provide reference for similar soft rock tests.