黏土矿物对软土结合水特征及力学性质影响的定量分析

QUANTITATIVE ANALYSIS OF CLAY MINERALS’INFLUENCE ON BOUND WATER CHARACTERISTICS AND MECHANICAL PROPERTIES OF SOFT SOILS

黏土矿物对软土结合水特征及力学性质的影响尤为重要,但国内研究多侧重于宏观物理力学性质层面。在微观层面探讨黏土矿物对软土工程性质的影响为此研究重点,利用X射线衍射仪(XRD)测得各地软土的矿物成分,并用同步热分析仪对各地软土进行热重分析(TG)和微商热重法分析(DTG)。试验结果显示,软土的黏土矿物含量与其吸附水含量正相关,其中蒙脱石含量对软土吸水性影响巨大;软土的TG与DTG曲线与其所含黏土矿物类型、含量有关,失重曲线在一定程度上可以体现软土中黏土矿物类型,DTG曲线中的失重谷对软土中的矿物类型起到一定的指示作用。

We study the influence of clay minerals on bound water characteristics and mechanical properties of soft soils.We first use X-ray diffractometry(XRD)to define the mineralogical composition of the soft soils.We also analyze the soft soils under thermogravimetric analysis(TG)and micro-commercial thermogravimetric analysis(DTG)with a simultaneous thermal analyzer.Based on the above analyses,we learn TG and DTG curve features of the soft soils in Huizhou,Shantou,Yangjiang,Zhanjiang,and Shenzhen.These analyses contribute to determining bound water content and boundaries.The test results are as follows.The clay mineral content of the soft soils positively correlates with the adsorbed water content of the soft soils,among which montmorillonite content has a greater influence on the water absorption of the soft soils.As the TG and DTG curves of the soft soils relate to clay mineral types and content,weight-loss valleys in DTG carves may indicate clay mineral types in the soft soils.In addition,we find it difficult to define the boundary between strongly bound water and weakly bound water solely based on TG and DTG curves.