CFG桩复合地基在全风化岩无砟轨道路基沉降控制中的应用研究

Study on Application of CFG Piles Composite Foundation in Settlement Control of Subgrade in Wholly-weathered Rock for Ballastless Track

以全风化岩作为无砟轨道的路基，必须进行加固。目前，对山区全风化岩CFG桩复合地基工后沉降的计算参数如何选取的研究不多，而高速铁路设计规范对无砟轨道路基工后沉降控制的要求极为严格。针对山区全风化岩采用CFG桩进行加固，并对其复合地基工后沉降计算参数的选取加以分析。研究结果表明：全风化层CFG桩复合地基的沉降计算采用压缩模量计算方法更为合理，同时对于不同地区、不同性质全风化层应分别建立压缩模量与标贯击数之间的经验关系式；CFG桩在穿过具有明显黏性土特性的全风化岩层后，结合沉降计算，再往下至少进入深层1—2m，地层含水量较大时，桩长宜再加长。

The subgrade in wholly-weathered rock for ballastless track has to be reinforced. Currently, there are few researches on parameter selection for calculation of post-construction settlement of CFG piles composite foundation in mountainous wholly-weathered rock area, while the requirements controlling post-construction settlement of subgrade for ballastless track in the code for design of high-speed railway is severe. The study result shows that the method calculating settlement of CFG piles composite foundation in wholly-weathered strata, which adopts compression modulus, is more reasonable, and for the wholly-weathered strata in different regions and with different natures, empirical correlations between compression modulus and SPT blow count should be developed respectively; when CFG piles pass through wholly-weathered rock with obvious cohesive soil characteristics, they should, combining the settlement calculation, go down into deeper stratum at least 1 - 2 m, or the pile length should be increased if the strata have higher water content.