云桂铁路原状膨胀土压缩特性试验研究

以云桂铁路弥勒膨胀土为研究对象,通过取原状膨胀土开展一维固结试验,研究了弥勒膨胀土的压缩特性、超固结特性及次固结特性。研究结果表明：弥勒膨胀土属于中等压缩土,其压缩系数随固结压力的增大而减小,曲线呈负指数变化特征；弥勒膨胀土地基15 m深度范围内具有超固结特性,其超固结比OCR为3.14～0.99,OCR 沿地基深度方向呈衰减变化；弥勒膨胀土具有明显的次固结特性,其次固结系数Cα随固结压力的变化而变化,次固结系数Cα与压缩指数Cc的比值基本是一个常数,Cα/Cc≈0.0218。试验及结果分析对铁路工程建设具有一定的指导意义。

Test Study of the Compression Property of the Undisturbed Expansive Soil Along the Yun-Gui Railway

With the Mile expansive soil as the obj ect of our study,a series of one-dimensional consolidation tests are made of the soil samples taken from different soil layers around Mile town along the Yun-Gui Railway to study the compression property,over-consolidation property and secondary consolidation property of the Mile expansive soil.It is found that the expansive soil in Mile is medium in compressibility,whose coefficient of compression decreases with the increase of the consolidation pressure, demonstrating an negative exponential function.Within the range of 1 5 metres,the foundation of the Mile expansive soil shows the over-consolidation property,whose over-consolidated ratio （OCR）is 3.14～0.99,which decreases with the increase of the depth of the foundation.The expansive soil in Mile has the distinct property of secondary consolidation,whose coefficient of secondary consolidation Cαvaries with the change in the consolidation pressure,and the ratio of the secondary consolidation indexCαand the compression indexCc is fundamentally a constant,namely,Cα/Cc ≈0.0218.The tests and the analysis of the test results may serve as a useful guide to the construction of railway engineering projects.