泥炭土作为一种特殊质土,其物理力学特性对工程建设施工影响极大。为探究高原沼泽相泥炭土的物理力学特性,针对昆明市第十四水质净化厂基坑揭露的沼泽相泥炭土开展了一系列室内物理力学试验,对泥炭土基本物理特性、固结变形特性及抗剪强度特性进行了分析。结果表明:该泥炭土工程性质较差,具有含水率较高、液塑限高、压缩性高、抗剪强度低等特性;固结过程中,随法向荷载的增加,泥炭土孔隙比近似呈线性减小趋势,单位沉降量近似呈线性增大趋势;固结系数与压缩系数的变化规律相似,呈先增大后减小的趋势;压缩模量与压缩系数成反比,先减小后增大;快剪试验下泥炭土剪切变形以塑性变形为主,剪应力与剪切位移呈现出先增大后趋于稳定的规律。
As a kind of special soil, the physical and mechanical properties of peat soil have a great influence on the construction of the project. In order to investigate the physical and mechanical properties of plateau bog phase peat soil, a series of indoor physical and mechanical tests were carried out on peat soil samples belonging to the Quaternary bog phase stratum exposed in the foundation pit of the 14th Water Purification Plant in Kunming City, and the basic physical properties, consolidation and deformation properties, and shear strength properties of the peat soil were analyzed. The test results showed that: the peat soil showed poor engineering properties, with high water content, high liquid-plastic limit, high compressibility and low shear strength. During the consolidation test of peat soil, with the increase of the normal load received, its pore ratio was approximately linearly decreased, and the unit settlement was approximately linearly increased; the change rule of consolidation and compression coefficient was similar to the trend of increasing first and then decreasing; the compression modulus was inversely proportional to the compression coefficient which was reduced first and then increased. The straight shear test of peat soil has indicated that its shear deformation is dominated by plastic deformation, the damage mode is plastic damage, and the shear stress and shear displacement exhibit the law of growing first and then tends to stabilize.
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