【作者】 李新召；

【导师】 刘高；

【作者基本信息】 兰州大学 ， 岩土工程， 2008， 硕士

【摘要】 柱锤冲扩桩法复合地基是一种较新的复合地基,因其对桩间土挤密效果好、经济、适用性强而得到越来越广泛的应用。然该类复合地基的理论研究相对滞后,其沉降计算远远落后于工程实践。在湿陷性黄土区应用柱锤冲扩桩法复合地基,消除黄土的湿陷性,控制工程沉降,应用甚少,沉降理论部分的研究几近空白。本研究以郑西客运专线里程DK355+200处湿陷性黄土区实体试验段柱锤冲扩桩部分为工程背景,以Midas/GTS软件为计算软件,通过复杂繁琐的数值计算,得到湿陷性黄土区DDC复合地基的复合模量计算的简单方法,为其沉降计算提供基本参数,并据此对该区DDC复合地基进行优化设计。分析研究大量的现场调研资料以及丰富的试验和监测资料,同时查阅国内外大量的参考文献,以数值计算作为主要研究方法,通过桩—桩间土分离式计算,得到复合地基分层沉降量;据单层复合地基沉降量反演每一层复合模量;探求桩体模量、桩间土模量和置换率与其对应的复合地基单层模量的关系,从而得到湿陷性黄土区DDC复合地基复合模量的表达式;以本文复合模量表达式计算所得的复合模量为基本参数,用分层总和法计算试验段复合地基的沉降,进一步说明印证本文提出计算式的合理性。以反演计所得到的单层复合模量为基础,采用按沉降控制设计思路,对郑西客运专线湿陷性黄土区柱锤冲扩桩复合地基进行优化设计。更多还原

【Abstract】 Composite foundation with piles thrusted-expanded in columnhammer (DDC) is a relatively new composite foundation, which is increasingly applied in a wide range just because their good effect on the compaction of soil among piles and their strong economic performance and applicability. However, the theoretical research on such foundation has lagged behind, and the settlement calculation lags far behind the engineering practice. The application of composite foundation DDC in collapsible loess areas, which is to eliminate the collapsibility of loess and control project settlement, is in a small number and the study on the settlement part is almost empty.Taking the DDC in the entity test in collapsible loess areas along Zhengzhou-Xi’an Passenger Line Mileage DK355+200 as the project background, the Midas/GTS software as the calculation software in this study, through complicated by the numerical calculation, a simple calculation method for the composite modulus calculation of the composite foundation with DDC in the collapsible loess areas, providing basic parameters for the settlement calculations, and accordingly making optimized design for the composite foundation with DDC in this area.Making analysis on the a lot of scene research data and a wealth of testing and monitoring information, referring to many reference literature at home and abroad, taking the numerical calculation as the main research methods, through the calculation of the separation formula of the piles and the soil among piles, the stratified settlement of composite foundation is achieved; according to the settlement of monolayer composite foundation, each layer composite modulus can be inversed; the pile modulus, the modulus of the soil among piles, the replacement rate and the relationship of its corresponding single-layer composite foundation are explored, which will provide the expression of the composite modulus of the composite foundation with DDC in the collapsible loess areas; the formula proposed in this paper will be proved reasonable by taking the composite modulus calculated through the composite modulus expression in this paper as the basic parameters and by using the settlement of the composite foundation along the testing segment.Based on the single-layer composite modulus achieved by the inversion, by using the settlement control design, the design of composite foundation with DDC along the Zhengzhou-Xi’an Passenger Line in the collapsible loess area has been optimized.更多还原