水泥搅拌桩加固松花江河漫滩相软土地基应用研究

发布时间：2018-01-19 23:02

本文关键词： 道路工程软土沉降地基处理水泥搅拌桩　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：在高速公路路基施工中，公路经常会穿越一些工程地质条件不良的软土地带，软土地基会对公路路基稳定性产生严重的危害，同时，其不均匀沉降也是导致路面早期破坏的主要原因之一。因此，软土地基处理方法和沉降观测的研究对公路建设十分重要。面对这些软土地基处理的需要，复合地基处理方法得到了广泛应用，其中，水泥搅拌桩法以施工速度快，施工过程中无振动、无噪音、无地面隆起，对周围环境和建筑物不产生有害影响等优点而日益受到关注。哈尔滨市松花江漫滩区软土由松花江曲流作用垂向沉积形成，属河漫滩相软土，其厚度分布不均匀，主要成分为淤泥质土、粉质粘土和粉砂土，具有显著的区域特点。论文依托哈尔滨市松北区“哈尔滨科技创新城193规划路建设项目”，试验路段位于K0+380~K0+620路段，属于松花江河漫滩区，原始地貌为湿地，后采取“吹砂筑岛”施工工艺，利用绞吸式挖泥船获取的江沙从堤岸在道路工程位置筑起用于建设的“大岛屿”，在道路地基土中有2~6m厚的软土地基，成分为淤泥质土、粉砂和粉质粘土，工程地质条件较差，此路段软土路基处理选用水泥搅拌桩复合地基处理法。论文首先通过现场地质勘查得出研究区软土层的位置和厚度，并对各个深度的土样进行了室内物理性质试验和直接剪切试验，，得到各土层的物理性质参数以及粘聚力和内摩擦角，以了解试验路段地基土的抗剪强度指标。然后对研究区试验路段所采用的水泥搅拌桩法加固道路软土地基的设计、施工工艺等进行了探讨，分析了质量控制的关键问题，重点研究了施工过程中质量控制、检测检验以及工后沉降控制。最后，在研究区的典型路段K0+400和K0+500断面均布置了沉降监测点，对道路的左路肩、中央位置和右路肩等位置的沉降数据进行定期不间断的监测，通过一年多的实测数据，监测出水泥搅拌桩法处理后的道路最终沉降量变化，研究水泥搅拌桩处理后的试验路段地基稳定性及沉降特性，分析水泥搅拌桩处理松花江河漫滩相软土地基的效果，并分析影响沉降的主要原因。研究表明：监测所得水泥搅拌桩的实际沉降小于理论的计算值，说明试验段路基处理效果良好，可以满足工后沉降要求，同时也表明研究路段的水泥搅拌桩桩设计方案合理。由此可鉴水泥搅拌桩通过加固道路的地基承载力，减少了道路地基工后沉降。
[Abstract]:In the highway roadbed construction, the highway often passes through some engineering geological condition bad soft soil belt, the soft soil foundation will produce the serious harm to the highway subgrade stability, at the same time. The uneven settlement is also one of the main reasons leading to the early destruction of pavement. Therefore, the research of soft soil foundation treatment and settlement observation is very important for highway construction. In the face of the need of these soft foundation treatment. The composite foundation treatment method has been widely used, among which, the cement mixing pile method has a fast construction speed, no vibration, no noise, no ground uplift during the construction process. More and more attention has been paid to the advantages of no harmful effects on the surrounding environment and buildings. The soft soil in Songhua River floodplain area of Harbin City is formed by the vertical deposition of Songhua River meandering. It belongs to the soft soil of the floodplain facies and its thickness distribution is uneven. The main components are silt clay and silty sand. It has remarkable regional characteristics. The paper relies on Harbin Songbei District "Harbin Science and Technology Innovation City 193 Planning Road Construction Project", the experimental road section is located at K0380 and K0620. It belongs to Songhua River floodplain area, the original landform is wetland, after adopting the construction craft of "blowing sand to build island", the "big island" for construction is built from the embankment in the position of road engineering by using the sand obtained by the suction dredger. There are two or six meters thick soft soil foundation in the road foundation, which is composed of silty soil, silty sand and silty clay, and the engineering geological conditions are poor. The cement mixing pile composite foundation method is used to treat the soft soil subgrade in this section. Firstly, the location and thickness of soft soil layer in the study area are obtained through the field geological survey, and the indoor physical property test and direct shear test are carried out for each depth of soil sample. The physical properties, cohesion and internal friction angle of each soil layer are obtained. In order to understand the shear strength index of the foundation soil in the test section, the design and construction technology of the cement mixing pile method used in the test section to strengthen the soft soil foundation of the road are discussed. The key problems of quality control are analyzed, and the quality control, inspection and settlement control after construction are studied. Settlement monitoring points were arranged at sections K0400 and K0500 of typical sections in the study area. The settlement data of the left shoulder, center position and right shoulder of the road were monitored on a regular and uninterrupted basis. Based on the measured data of more than one year, the change of the final settlement of the road after the treatment of cement mixing pile is monitored, and the stability and settlement characteristics of the test section after the treatment of cement mixing pile are studied. This paper analyzes the effect of cement mixing pile on treating soft soil foundation of Songhua River floodplain, and analyzes the main reasons of influencing settlement. The research shows that the actual settlement of cement mixing pile obtained by monitoring is less than the calculated value of theory. The results show that the test section of the subgrade treatment effect is good, can meet the requirements of post-construction settlement, but also shows that the study section of cement mixing pile design scheme is reasonable, which can be used to identify the cement mixing pile through the reinforcement of the foundation bearing capacity of the road. It reduces the settlement of road foundation after construction.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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