论文部分内容阅读
影响天然硫酸盐渍土强度的因素众多,规律难以探索。为确定含盐量对硫酸盐渍土抗剪强度的影响,通过直剪试验研究了不同含盐量的硫酸盐渍土抗剪强度特性。研究表明:在直剪应力状态下,剪应力-剪切位移关系曲线有应变硬化(加工硬化)和应变软化(加工软化)两种形态,取决于含盐量、含水量、法向应力等因素。抗剪强度包线近似为折线型,与传统结构性土体包线形态一致,表明了硫酸盐渍土在直剪应力状态下仍然属于结构性土体。易溶盐含量对抗剪强度影响较大,总的变化趋势是:随着含盐量的增加,相同法向应力作用下的硫酸盐渍土的抗剪强度有不同程度的先减小后增大再减小的特点。当含水量ω=21%时,粘聚力c随易溶盐含量的增大呈指数形式的增长,c∈[2.9kPa,10.4kPa];当ω=25%时,c∈[3.2kPa,12.4kPa];内摩擦角φ随易溶盐含量的增大变化范围较小,总体的变化趋势呈现出先减小后增加再减小的特点;当ω=21%时,φ∈[11.5°,13.4°];在ω=25%时,φ∈[10.6°,12.9°]。
Many factors affect the strength of natural sulfate soil, the law is difficult to explore. In order to determine the influence of salinity on the shear strength of sulfate saline soil, the shear strength characteristics of sulfate saline soil with different salt content were studied by direct shear test. The results show that there are two kinds of strain hardening (hardening) and strain softening (processing softening) under the condition of direct shear stress, which depend on the factors of salt content, water content and normal stress . The shear strength envelope is approximately a polygonal line, which is consistent with that of the traditional structured soil envelope. It shows that the sulfate-based soil still belongs to the structural soil under direct shear stress. The content of soluble salt has a great influence on the shear strength, and the general trend is as follows: with the increase of salt content, the shear strength of sulfate saline soil under the same normal stress is decreased first and then increased Big and then reduce the characteristics. When the water content ω = 21%, the cohesion c increases exponentially with the increase of the soluble salt content, c ∈ [2.9kPa, 10.4kPa]; when ω = 25%, c∈ [3.2kPa, 12.4 kPa]. The internal friction angle φ is smaller with the increasing of soluble salt content, and the overall change tendency decreases first and then increases and then decreases. When ω = 21%, φ∈ [11.5 °, 13.4 °]; φ ∈ [10.6 °, 12.9 °] at ω = 25%.