珠江三角洲海相沉积软土压缩和剪切变形特性试验研究

Compression and Shear Deformation Properties of Marine Soft Soil Deposits in the Pearl River Delta

摘要:

为了研究近代海相沉积软土的变形特征，本文对珠江三角洲河口地区的全新世海相沉积的软土进行了室内单轴压缩与不同围压下作用下的三轴固结不排水（CU）、不固结不排水（UU）的剪切试验。试验结果表明：原状土和重塑土样的孔隙比随压力的增大而下降，且与加压方式有密切关系，加压幅度越小，土的扰动破坏越小；原状土样固结系数随着压力增加而递减，整体近似符合指数函数分布，重塑土样固结系数随着压力增加逐渐增大，整体近似符合线性函数分布。在相同的固结压力下，原状土样的强度低于重塑土样的强度。土样的应力应变曲线为应变硬化型，且围压对重塑土的影响小于原状土。

Abstract:

In this work, Holocene-era soft soil deposits in the Pearl River Delta were sampled. The differences in the compression and shear deformation properties of undisturbed and reconstituted soils were determined through uniaxial compression tests, consolidated-undrained triaxial tests, and unconsolidated-undrained triaxial tests. Comparing the compression curves of undisturbed and reconstituted samples revealed that the void ratio of the two soils decreases as pressure increases and is closely related to compression method. The consolidation coefficient of the undisturbed soil sample decreases exponentially as pressure increases, whereas that of the reconstituted soil sample increases linearly with pressure. The results of the triaxial shear test showed that under the same consolidation pressure, the strength of undisturbed samples is lower than that of reconstituted samples. The stress-strain curves of soil samples reflect the occurrence of strain hardening. The influence of confining pressure on the reconstituted soil sample is smaller than that on the undisturbed soil sample.