【摘要】 【目标】特定环境和气候条件导致了泥炭质土独特的结构，其结构差异会使土的强度特性呈现出显著的差异。本研究探究了泥炭质土特有结构对泥炭质土工程性质的影响。【方法】为了诠释泥炭土强度的演变过程，对同一场地埋深分别位于10,19,25,39,50 m的5层原状土和重塑泥炭质土，进行不同围压条件下的三轴固结不排水剪切试验及电镜扫描试验。从应力-应变曲线、微观结构、峰值强度、残余强度、割线模量、有效应力路径、黏聚力和内摩擦角等方面的变化规律进行研究，分析不同围压及埋深对原状土和重塑泥炭质土力学特性的影响。【结果】原状土随围压和埋深增加的曲线形态逐渐由弱硬化转为弱软化，而重塑泥炭土曲线形态基本保持不变，呈弱硬化；从整体上看，重塑泥炭质土抗剪强度均高于原状土；泥炭土割线模量不仅随应变变化，还受围压、埋深和扰动情况的影响，在最大割线模量与围压的关系方面，重塑土表现出更好的线性关系且随着围压增加增幅较快。【结论】本研究进一步加深了对泥炭土力学特性的认识，对其工程设计及施工一定的指导意义。更多还原

【Abstract】 [Objective]The specific environmental and climatic conditions lead to the unique structure of peaty soil. The soil structural differences make significant differences of soil strength characteristics. The study investigates the influences of peaty soil unique structure on its engineering properties. [Method] To interpret the evolution process of peaty soil strength, the triaxial consolidated undrained shear tests and scanning electron microscopy tests were carried out under different confining pressures. The study subjects were 5 layers of undisturbed soil and remolded peaty soil collected from the same site at depths of 10, 19, 25, 39, 50 m. The variation rules were studied on the aspects of stress-strain curve, microstructures, peak strength, residual strength, secant modulus, effective stress path, cohesion and internal friction angle. The influences of confining pressure and burial depth on mechanical properties of undisturbed soil and remolded peaty soil were analyzed. [Result] The curve shapes of undisturbed soil are gradually varying from weak hardening to weak softening with the increase of confining pressure and burial depth; while the curve shape of remolded peaty soil basically remains unchanged and shows weak hardening. On the whole, the shear strength of remolded peaty soil is higher than that of undisturbed soil. The secant modulus of peaty soil is not only varying with strain, but also affected by confining pressure, burial depth and disturbance. In terms of relation between the maximum secant modulus and confining pressure, the remolded soil exhibits better linear relation and faster increase with confining pressure increasing. [Conclusion]The study further deepens the understanding of peaty soil mechanical properties, and has certain guiding significance for its engineering design and construction.更多还原