砼芯水泥土搅拌桩基坑支护的有限元分析

砼芯水泥土搅拌桩支护方法异于常用的支护方法,没有现成的经验可借鉴,用普通的近似方法分析和设计有较大难度。为了准确了解基坑支护结构的变形情况,确保工程安全,也为了便于该新型支护方法的推广,对该基坑支护形式进行了二维有限元分析。有限元分析中采用理想弹塑性模型,考虑了支护结构和土体之间的相互作用,并将计算结果与普通的近似方法计算结果进行了比较,发现用普通近似方法进行设计存在一定的安全隐患。对砼芯水泥土搅拌桩支护设计涉及到的水泥土桩长、方桩桩长、岩土的弹模、桩间距等关键参数进行了分析和讨论,最后对砼芯水泥土搅拌桩支护设计提出了可行建议。

FEM Analysis of Pit Supporting with Concrete Core Cement-Soil Mixed Pile

Concrete Core Cement-Soil Mixed Pile differs from the common method of retaining and protection of excavations.Since no experience is available for reference, it is difficult to analyze this type of supporting structure using the traditional approximate method.For purposes of ensuring the safety of construction,the two-dimensional finite element method is used in this paper to analyze the deformational characteristics of the supporting structure.The idealized elasto-plastic model is used in FEM numerical simulation with consideration of the interaction between soil and structure.Comparisons are made between the results of FEM and the ordinary approximate method,which show the latter has some shortcomings for analyzing this type of supporting structure.The critical parameters governing the behavior of this supporting structure are found to be the length of cement-soil pile,the length of concrete pile,the elastic modulus of soil and the pile spacing.On the basis of the analytical results,some suggestions are made which can be accepted in the design of concrete core cement-soil mixed pile.