广东西部沿海铁路江门南站软土土性参数随机场特性研究

Study on the Random Field Characteristics of Soil Parameters for Jiangmen South Station of Coastal Railway in West Guangdong

研究目的:广东西部沿海铁路江门南站范围内分布有较厚的软土,其成因为潭江入海口海陆交互相冲积,土性主要为淤泥质黏土和粉质黏土,局部有沙砾夹层,为了满足承载力及工后沉降的要求,路基基底必须采用复合地基进行加固。合理选择土性参数是复合地基设计的关键,由于土体是在自然条件下形成的,其性质表现出很大的变异性,所以采用概率分析方法设计复合地基显得更加合理。土性参数随机场特性研究可以为复合地基概率设计方法提供依据,本文利用CPT资料对江门南站软土土性参数的随机场特性进行了研究。研究结论:形成了比较系统的随机场研究方法,得到了主要土层的方差折减函数;统计得到了压缩模量、承载力及抗剪强度指标的均值和方差,利用方差折减函数对方差进行了修正,为路基概率设计方法提供依据。

Research purposes： In the area of Jiangmen South Station of coastal railway in western part of Guangdong Province, there is a thick layer of soft soil mainly with silt clays and partially with gravel interlayer due to the alluvion by sea and land in Tanjiang estuary. In order to meet the requirements of bearing capacity and post - construction settlement, the foundation base of subgrade must be reinforced into composite foundation. The proper selection of soil parameters is crucial to the design of composite foundation. As the soil body has been formed under natural condition, the soil has a great variability in characteristics. Thus, it is reasonable to use the probability method to design the composite foundation. The study on the random field characteristics of soil parameters can provide the basis for design of the composite foundation with probability method. This paper studies the random field characteristics of soil parameters for Jiangmen South Station with the CPT data. Research conclusions：The main reduction functions of variance of the main soil layers are obtained with systematic random field method. The average value and variance of compression modulus, bearing capacity and shear strength index are obtained with statistics. The reduction function of variance is used to modify the variance.