堆石料应力-应变特性大型三轴试验研究
发布时间：2018-08-18 10:27
【摘要】：通过对水布垭筑坝堆石料进行0.2~3.5 MPa围压下的大型三轴固结排水剪(CD)试验,分析了不同围压下堆石料的偏应力-轴应变关系及体应变-轴应变关系的变化规律;引入破坏强度和体变与围压的关系,采用临界偏应力σ_(cre)和临界体应变ε_(vcre)作为归一化因子对不同围压下的应力-应变关系试验结果进行归一化处理,建立了不同围压下的应力-应变关系表达式,并将计算预测与试验结果进行对比验证。研究表明:对于颗粒级配确定的密实堆石料,初始变形期存在一定的弹性增长阶段,且该直线段的斜率受围压的影响较大;低围压时表现为应变软化,先剪缩后剪胀为主的力学特性,且围压越低,剪胀效应越明显;高围压(0.8 MPa≤σ_3≤3.0 MPa)时表现为应变硬化、剪缩为主的特性;剪胀消失的临界围压处于0.45~0.8 MPa之间;超高围压(σ_33.0 MPa)条件下,虽表现为应变软化、剪缩的特性,但其应变软化的机制与低围压下不同;分析认为,超高围压下剪切过程中颗粒的相对破碎率达15%以上,颗粒破碎引起的堆石料强度降低大于围压的增大对堆石料强度的提高。峰值主应力比随围压的增大而降低,且随轴应变的增大而趋于一致。堆石料的破坏强度与围压呈线性相关。最后,通过计算预测结果证明了该应力-应变关系表达式的正确性。
[Abstract]:Based on the large triaxial consolidation drainage shear (CD) test under the confining pressure of 0.2 ~ 3.5 MPa for the rockfill material of Shuibuya dam, the variation law of the deformation stress-axial strain relationship and the body-strain-axial strain relationship of the rockfill material under different confining pressures are analyzed. By introducing the relationship between failure strength, bulk deformation and confining pressure, the critical deflection stress 蟽 _ (cre) and critical bulk strain 蔚 _ (vcre) are used as normalized factors to normalize the stress-strain relation test results under different confining pressures. The expression of stress-strain relationship under different confining pressures is established, and the calculated prediction is compared with the experimental results. The results show that there is a certain elastic growth stage in the initial deformation period for the dense rockfill material determined by particle gradation, and the slope of the straight section is greatly affected by the confining pressure, while the strain softening occurs when the confining pressure is low. The shear expansion effect is more obvious with lower confining pressure (0.8 MPa 鈮，
本文编号：2189182
[Abstract]:Based on the large triaxial consolidation drainage shear (CD) test under the confining pressure of 0.2 ~ 3.5 MPa for the rockfill material of Shuibuya dam, the variation law of the deformation stress-axial strain relationship and the body-strain-axial strain relationship of the rockfill material under different confining pressures are analyzed. By introducing the relationship between failure strength, bulk deformation and confining pressure, the critical deflection stress 蟽 _ (cre) and critical bulk strain 蔚 _ (vcre) are used as normalized factors to normalize the stress-strain relation test results under different confining pressures. The expression of stress-strain relationship under different confining pressures is established, and the calculated prediction is compared with the experimental results. The results show that there is a certain elastic growth stage in the initial deformation period for the dense rockfill material determined by particle gradation, and the slope of the straight section is greatly affected by the confining pressure, while the strain softening occurs when the confining pressure is low. The shear expansion effect is more obvious with lower confining pressure (0.8 MPa 鈮，
本文编号：2189182
本文链接：https://www.wllwen.com/kejilunwen/shuiwenshuili/2189182.html
