压实度和基质吸力对土石混合填料强度变形特性的影响研究

发布时间：2019-07-19 14:39

【摘要】：针对土石混合料高填方工程分析计算参数和模型确定难题,采用非饱和土三轴仪进行了控制基质吸力和净围压的36个固结排水剪切试验,定量研究了压实度、基质吸力、配合比对非饱和重塑混合料强度变形特性的影响,建立了非饱和压实土抗剪强度、切线变形模量和切线体积模量修正算法表达式。试验结果表明:破坏应力、黏聚力随吸力的增加基本呈线性增长,吸力变化对有效内摩擦角影响不大;破坏应力与强度参数随压实系数的提高而增大;土石比为4:6的土样破坏应力和强度参数整体略高于2:8的土样,有效黏聚力随粉质黏土含量的增加而增大。配合比和压实系数相同的土样,净围压或吸力越大,试样强度越大,体变逐步由剪缩趋于剪胀;净围压和吸力相同的土样,在相同配合比时,压实系数越高,应变曲线逐渐由应变硬化型向理想弹塑型转变,低净围压下部分土样趋于应变软化型。修正后的非饱和土非线性增量本构关系符合大面积填方工程实际,可用于高填方地基变形计算和高填方边坡稳定性分析。
[Abstract]:In order to solve the problem of calculating parameters and model determination of high fill engineering of soil-rock mixture, 36 consolidated drainage shear tests were carried out to control matrix suction and net confining pressure by using unsaturated soil triaxial apparatus. The effects of compaction degree, matrix suction and mix ratio on strength and deformation characteristics of unsaturated remolded mixture were quantitatively studied, and the modified algorithm expressions of shear strength, tangent deformation modulus and tangent volume modulus of unsaturated compacted soil were established. The experimental results show that the failure stress and cohesion increase linearly with the increase of suction, and the variation of suction has little effect on the effective internal friction angle, the failure stress and strength parameters increase with the increase of compaction coefficient, and the effective cohesion increases with the increase of silt clay content when the failure stress and strength parameters of soil samples with 4:6 ratio of soil to rock are slightly higher than that of 2:8, and the effective cohesion increases with the increase of silt clay content. The greater the net confining pressure or suction is, the greater the strength of the sample is, and the larger the net confining pressure or suction is, the greater the strength of the sample is, and the higher the compaction coefficient is when the net confining pressure and suction are the same, the higher the compaction coefficient is, the more the strain curve changes from strain hardening type to ideal elastic-plastic type, and some soil samples tend to strain soften type under low net confining pressure. The modified nonlinear incremental constitutive relation of unsaturated soil accords with the practice of large area filling engineering and can be used for deformation calculation of high fill foundation and stability analysis of high fill slope.
【作者单位】：兰州理工大学土木工程学院;兰州理工大学西部土木工程防灾减灾教育部工程研究中心;
【基金】：甘肃省科技重大专项计划项目(No.1302FKDA030) 教育部长江学者创新团队支持计划项目(No.IRT13068,No.IRT_17R51)~~
【分类号】：TU41;TU45

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