杭州湾新区深部高液限黏土微观组构研究

Research on microstructure of deep high liquid limit clay in Hangzhou Bay NewArea

宁波杭州湾新区地处长江入海口南侧,地质环境和水动力条件复杂,深部高液限黏土力学性质异于同时代形成的黏土特性,黏土工程地质性质与黏土的微观结构密切相关。从X射线测试(XRD和XRF)物相分析以及扫描电测试(SEM)成像分析两方面对杭州湾新区深部高液限黏土微观组构研究,结果表明:1)杭州湾新区深部高液限黏土化学成分以SiO_(2)和Al_(2)O_(3)为主,与其他海陆交互相、海相软土一样,黏土矿物也以伊利石为主;2)该套土层整体分布均匀,浅部、深部土样测试结果总体较为接近,与浅部土相比,深部土的孔隙数量增加但平均直径减小;3)该套黏土主要以角、边与面或边与边的搭接排列,即为絮凝状结构,比较均匀,且各向同性较好。

Ningbo Hangzhou Bay New Area is located on the south side of theYangtze River estuary,with complicated geological environment and hydrodynamic conditions.The mechanical properties of deep high liquid limit clay are different from those of contemporaneous clay.The engineering geological properties of clay are closely related to its microstructure.In this paper,the microstructure of the deep high liquid limit clay in Hangzhou Bay NewArea is studied using X-ray test(XRD and XRF)phase analysis and scanning electrical test(SEM)imaging analysis.The results show that:(1)The chemical composition of the deep high liquid limit clay in Hangzhou Bay New Area is mainly SiO_(2) and Al_(2)O_(3),which is the same as other marine-land interactive facies and marine soft clay.Clay minerals are also dominated by illite;(2)The overall distribution of the soil layer is uniform with generally similar test results between the shallow soil and deep soil samples.Compared with the shallow soil,the number of pores in the deep soil increases but the average diameter decreases;(3)According to the SEM test,the clay is mainly arranged in the overlapping pattern of corners,edge-to-face or edge-to-edge.It’s a flocculent structure,which is relatively uniform and has good isotropy.