Comparative analysis of static strength characteristics of two kinds of silty clay
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摘要: 以南京与无锡的两种粉质黏土为研究对象，通过使用TSZ-2全自动三轴仪对这两种土在饱和以及非饱和状态下的静强度进行测定。对比分析两种土在饱和状态下，其原状样与扰动样之间抗剪强度的差异，以及两种土在非饱和状态下不同的初始含水率对其抗剪强度产生的影响。得出无锡土样较南京土样具有含水率低、密度高、孔隙比小、压缩性低、静强度高的特点，但扰动作用对无锡饱和土造成的影响较大，而南京土样受扰动作用影响小。确定非饱和粘性土的抗剪强度与含水率以及颗粒级配存在关联，从而导致两种土非饱和状态的抗剪强度存在差异。Abstract: Taking two types of silty clays from Nanjing and Wuxi as the research object, the static strength of these two kinds of soil in saturated and unsaturated states was measured using the TSZ-2 automatic triaxial instrument. The difference in shear strength between the original and disturbed samples of the soil in the saturated state, and the influence of the initial water content of the soil in the unsaturated state on the shear strength are studied. The comparison of test results shows that Wuxi soil has the characteristics of smaller water content, higher density, smaller void ratio, smaller compressibility, and higher static strength than Nanjing soil. However, the disturbance effect has a greater impact on Wuxi saturated soil compared to Nanjing soil. The shear strength of unsaturated cohesive soil is related to the particle gradation, resulting in a difference in the shear strength of the two types of soil.
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Key words:
- static triaxial test /
- saturated soil /
- unsaturated soil /
- shear strength
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图 4 南京、无锡地区原状和重塑粉质黏土应力-应变曲线
Figure 4. Stress-strain curves of undisturbed and remolded silty clays in Nanjing and Wuxi areas
图 5 300 kPa围压下两种土原状和重塑粉质黏土静三轴实验结果
Figure 5. Static triaxial test results of two kinds of undisturbed soil and remolded silty clay under 300 kPa confining pressure
图 6 非饱和土样不固结不排水三轴试验结果
Figure 6. Unconsolidated and undrained triaxial test results of unsaturated soil samples
表 1 两种粉质黏土基本物理指标
Table 1. Basic physical indexes of two kinds of silty clay
地区 深度范围/m 土粒相对密度 密度/kg•cm−3 含水率 孔隙比e 塑限 液限 塑性指数Ip 南京 10—14 2.62 1.91 26% 0.547 23.4% 38.2% 14.8 无锡 7—12 2.456 2.05 19% 0.441 24.9% 41.3% 16.4 
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表 2 固结不排水抗剪强度指标
Table 2. Consolidated undrained shear strength index
抗剪强度指标 c/kPa φ/° 无锡原状土样 16.69 2.18 无锡重塑土样 9.46 1.74 南京原状土样 9.18 1.22 南京重塑土样 8.42 0.86
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