滇池泥炭土工程地质特性试验研究

【作者】 孙晓娟；

【导师】 侯克鹏； 赖正发；

【作者基本信息】 昆明理工大学 ， 岩土工程， 2006， 硕士

【摘要】 随着昆明市城乡建设的飞速发展，软基处理工程日益广泛和复杂化，然而在滇池盆地地区，工程地质性质较差的软土尤其是泥炭土分布广泛，对昆明市的经济建设带来许多问题。从目前关于软土的研究状况来看，泥炭土的研究理论方面不多。因此研究滇池地区泥炭土的工程特性，进行泥炭土软土地基处理，也就成为工程地质学和岩土工程的重要内容之一。本文主要对滇池附近泥炭土的工程地质性质进行试验研究。首先，选取滇池附近船房河岸边的一试验场地，对其进行了现场原位试验，包括静力触探试验、十字板剪切试验和扁铲侧胀试验。其中，特别引入的扁铲侧胀试验在云南省的岩土工程领域尚未推广开来，属于较新的原位试验方法。原位试验结果表明，滇池地区泥炭土属于高灵敏土，较其它类土的灵敏度大，说明结构性和扰动因素等对泥炭土强度的影响较大。扁铲原位试验的结果反映出泥炭土的含水量大，其土体内孔隙水压力也相应地比其它土类高，故其土体的抗剪强度有效值则更小。其次，在试验场地钻孔取样进行室内土工试验，包括各种土的物理指标试验和直剪、三轴剪切试验。结合试验结果分析了含水量变化对泥炭土的影响规律。通过曲线的拟合得出各物理力学指标之间的相关关系。通过不同原位试验间的力学指标相关性分析得出泥炭土的两大强度指标粘聚力和内摩擦角的数值关系。对三轴试验成果进行归一化处理并在此基础上进行了非线弹性分析，提出滇池地区泥炭土的应力—应变关系符合邓肯—张的双曲线模型关系，进而得到弹性模量的变化关系式。这对于边坡和基坑稳定以及沉降计算等方面具有一定的实际意义。更多还原

【Abstract】 With the highly development of Kunming city and countryside, the soft clay ground treatment is more widespread and complicate day by day. Distribution of the peat soil in Kunming Pond basin area is so extensive. As one of the soft soil that has the worse geotechnical engineering properties, peat soil brings a lot of questions to the economic construction of Kunming city. According to studying of peat soil, there are few research theories about it. So the studying of the project properties of peat soil of Kunming Pond and dealing with the peat soil foundation become one of the important contents of geotechnical engineering.This paper mainly carries on experimental study to the geological properties of peat land near Kunming pond.First, a test site was choosed by the bank of Chuanfang River in the Kunming Pond area. And the in-situ test have been carried here, that include static cone penetration, vane shear test and flat dilatometer test. Among them, flat dilatometer test belongs to a newer method of in-situ test which has not popularized in the field of geotechnical engineering in Yunnan Province. The in-situ test results show that the peat soil in Kunming Pond is the high sensitive soil. Its sensitivity is larger than the sensitivity of other kinds of soil. That proves structure and dynamic factor exercise a great influence on the strength of peat soil. The result of DTM test explained that peat soil has great water content. And Its pore water pressure is higher than other soil, so the effective stress is lower.Secondly, the laboratory experiment to the sample of peat soil was taken. It concludes experiments of physical parameter, direct shear test and triaxial test. According to the results of laboratory test, this paper analyzes the effect of water content on the parameter of shear strength of peat soil. Then, put forward to a formulation about the coherent strength and the fiction angle respectively and the relevant relations between every physics mechanics parameter. By the way of inductive method to deal with the results of triaxial test, and, through the nonlinear elastic analysis based on the normalization, it was proposed that the stress-strain relation of peat soil conforms to hyperbolic model by Duncan&Chang. And then the change relational expression of the modulus was obtained through analyzing. All of these will contribute to calculating the stability of slope and deep excavation as well as the displacement of foundation.更多还原