软土变形指标与初始孔隙率的相关性分析

根据上海地区不同土层软土的一维和等向固结试验,得到一维固结下压缩指数C_c和回弹指数C_s与修正剑桥模型参数λ和κ之间的关系。鉴于室内试验耗时过长,而通过土样的基本物理指标(天然含水率w_n、孔隙比e₀、液限w_L和塑性指数I_p)来推算压缩指数和回弹指数是一个快捷有效的方式,对比发现土的变形指标与基本物理指标间存在一定的相关性。结果表明:C_c/n₀与C_c,C′_s/n₀与三轴试验各向同性固结下得到的C′_s之间存在较好的线性关系,并给出了对应的关系式。由此,上海地区软土的变形指标可通过初始孔隙率来估算。在已有试验数据的基础上,总结分析我国沿海多个地区(广州、天津、深圳、温州、福州等)压缩指数试验数据,发现沿海地区软土压缩指数与初始孔隙率之间均存在较好的线性关系,并给出了对应的关系式。

Correlations between Deformation Indexes and Initial Void Ratio of Soft Clay

One-dimensional and isotropic consolidation tests were carried out on clay of varied depth in Shanghai to acquire the compression index C_c and the rebound index C_s and their relations with parameters parameters λ and κ in the modified Cambridge model. However, laboratory tests are time-consuming and expensive. Empirical relations need to be developed to predict compression index using physical indices (especially natural water content w_n, initial void ratio e₀, liquid limit w_L and plastic index I_p) of soil which are relatively easier to obtain. Highly linear relations between C_c/n₀ and C_c as well as C′_s/n₀ and C′_s were found, and corresponding relational expressions were established. Hence, the deformation index of soft soil in Shanghai can be estimated by void ratio. In addition, according to test data of soft soil in coastal areas in China, including Guangzhou, Tianjin, Shenzhen, Wenzhou, and Fuzhou, an empirical function between C_c/n₀ and C_c was constructed to predict compression index of soft soil in some coastal areas in China (Guangzhou, Tianjin, Shenzhen, Wenzhou, and Fuzhou) for preliminary engineering design.