Influence of Matrices on Mechanical Properties of Miscellaneous Fillings
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摘要: 采用中型三轴仪,对南京吉山矿区堆放场的杂填土进行试验研究。通过对含石量为30%的粉质黏土、砂土、粉土三种基质的杂填土分别进行不同围压下的剪切试验,分析基质对杂填土力学性质的影响。结果表明:三种基质杂填土的(σ1-σ3)-ε1关系曲线为双曲线,属应变硬化性曲线。相同围压下,在低围压时,随着基质的变化,杂填土破坏时的偏差应力相差不大,在高围压时,随着基质的变化,杂填土破坏时的偏差应力存在着显著差异。同一基质下,随着围压的增大,杂填土破坏时的偏差应力也逐渐增大,其中基质为粉土的杂填土破坏时的偏差应力增量最大。基质为粉质黏土和粉土的杂填土,始终呈剪缩状。砂土基质的杂填土,随着轴向应变的增大,体应变变化较为复杂;在围压为100 kPa时,砂土先呈现减缩后呈现剪胀的变化规律;在围压为200,400 kPa时,始终呈剪缩状。通过对强度参数特性指标和本构模型计算参数的综合比较,发现基质是影响杂填土力学参数的一个重要因素。
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关键词:
- 杂填土 /
- 基质 /
- 中型三轴试验 /
- 应力-应变-强度特性
Abstract: By using the medium-sized triaxial apparatus, the miscellaneous fill in the dump of the Jishan mining area in Nanjing was studied. Through the confining pressure tests of 100 kPa, 200 kPa and 400 kPa for miscellaneous fillings of silty clay, sand and silt with the stone content of 30%, the influence of matrixs on the mechanical properties of miscellaneous fillings was analyzed. The results showed that the (σ1-σ3)-ε1 curves of miscellaneous fillings were hyperbolic and displayed a strain hardening tendency. Under the same confining pressure, when the confining pressure was low, with the change of the matrixs, the differences for deviation stress of miscellaneous fillings were very similar. When the confining pressure was high, with the change of the matrixs, the differences of deviation stress of miscellaneous fillings were significant. For the same matrix, with the increase of confining pressure, the deviation stress differences of miscellaneous fillings increased gradually, and the increase of deviation stress differences for miscellaneous fillings of silt was the largest. For the miscellaneous fillings of silty clay and silt, the volume was always in shear shrinkage. With the increase of axial strain, changes for the volume strain of miscellaneous fillings of sand were more complex. When the confining pressure was 100 kPa, the miscellaneous fillings of sand showed a shear shrinkage tendency first, and then dilatancy. When the confining pressure was 200 kPa and 400 kPa, sand was always in shear shrinkage. Based on comprehensive comparisons of strength parameters and constitutive model parameters, it indicated that the matrix was an important factor influencing the mechanical parameters of miscellaneous fillings. -
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