川西地区紫色土抗剪强度水敏性试验研究

The water sensitivity of soil shear strength is an important reference basis for engineering stability research and design. In order to study the influence law of water content on the shear strength of purple soil in western Sichuan and reveal its water-sensitive characteristics of shear strength, indoor direct shear tests were carried out on remolded purple soil with different water contents under different principal stresses. The results show that: 1) The shear strength is water-sensitive, and its strength first increases and then decreases with the increase of water content, and reaches a peak when the water content is 15%. 2) The shear strength is affected by the principal stress. When the principal stress increases from 0 kPa to 400 kPa, there is a significant positive correlation between the strength and the principal stress at the same water content. 3) The cohesion is significantly affected by the water content, which first increases and then decreases with the increase of water content, and the peak value of 103.40 kPa is obtained when the water content is 15%, while the internal friction angle has a significant negative correlation with the water content. 4) The shear stress - shear displacement curves of the soil successively present strain hardening type and weak hardening type with the increase of water content. The research results further enrich the understanding of the water sensitivity of purple soil in western Sichuan and can provide a reference basis for the subsequent engineering construction in western Sichuan.

土体抗剪强度水敏性是工程稳定性研究与设计的重要参考依据。为了研究含水率对川西地区紫色土抗剪强度的影响规律,并揭示其抗剪强度的水敏特性,在不同主应力下对不同含水率的重塑紫色土进行了室内直剪试验。结果表明: 1)抗剪强度具有水敏感性,其强度随含水率增加先增大后减小,并在含水率15%时取得峰值。2)抗剪强度受主应力影响,当主应力由0kPa增加至400kPa时,相同含水率下强度与主应力具有显著的正相关性。3)黏聚力受含水率影响明显,表现为含水率增大其先增大后减小,峰值103.40kPa在含水率15%处取得,而内摩擦角与含水率具有显著的负相关性。4)土体的剪应力-剪切位移曲线随含水率递增依次呈现应变硬化型和弱硬化型。该研究成果进一步丰富了对川西地区紫色土水敏性的认识,可为后续川西工程建设提供参考依据。