珠海横琴软土工程性质与埋深相关性研究

Study on Correlation Between Soft Soil Engineering Characteristics and Burial Depth in Hengqin New Area of Zhuhai City

[目的]为研究珠江口西岸广泛分布软土的工程性质,指导区域性工程建设。[方法]以珠海市横琴新区某建设项目的岩土工程勘察数据为基础,借助现代数理统计手段分析其物理力学性质参数,研究该区软土工程特性及参数相关性。[结果]结果表明:横琴新区软土具有高含水率、高孔隙比、流塑状态、高压缩性、低强度值、欠固结性等典型的软土特征;其天然含水率随埋深增加而减少,塑性指数随埋深增大而增大,软土接触性状随深度增大变得更好;由直接快剪试验得到的抗剪强度指标随埋深增大而增大,而由固结快剪试验与三轴固结不排水抗剪强度(CU)试验得到的抗剪强度指标没有呈现出规律性;抗剪强度呈现出较好的规律性,随埋深增大而增大。[结论]该区软土深厚,物理力学性质与工程特性随深度规律地变化,其中埋深18～27 m之间的软土性状在水平方向上变化较大,建议对该区软土勘察时,宜根据工程设计特点必要时细分土层。

[Introduction]In order to study the engineering properties of soft soil widely distributed in the West Bank of the Pearl River Estuary and guide the regional engineering construction.[Method]The physical and mechanical parameters of a construction project in Hengqin New Area of Zhuhai City were analyzed by means of modern mathematical statistics;the engineering characteristics and parameter correlation of the soft soil in the area were studied based on the geotechnical investigation data.[Result]The results show that the soft soil in Hengqin New Area has the typical characteristics of high water content,high porosity ratio,fluid-plastic state,high compressibility,low strength value and under-consolidation,its natural water content decreases with the increase of buried depth,plasticity index increases with the increase of buried depth,and the contact behavior of soft soil becomes better with the increase of depth;The shear strength index obtained by the fast shear test increases with the buried depth,but the shear strength index obtained by the consolidated fast shear test and the triaxial consolidated undrained shear strength(CU)test shows no regularity;The shear strength shows a good regularity,and increases with the buried depth.[Conclusion]Due to the soft soil in this area is deep,and its physical and mechanical properties and engineering properties change regularly with depth.The soft soil properties between 18m and 27m in depth change greatly in horizontal direction.It is suggested that the soil layers should be subdivided according to the engineering design characteristics when it is necessary.