富水充填材料蠕变及其硬化体内水分损失特征

Creep and water loss characteristics in hardening bodies of water-rich filling materials

为探讨富水充填材料在时效作用下的变形及其硬化体内水分损失特征,本文研究一定水固质量比的富水充填材料在不同应力水平下的蠕变性能,并通过扫描电镜观察、差热-热重分析等实验探讨充填体在蠕变过程前后的形变特征、水分损失及其与外界荷载的关系.结果表明:水固质量比为2.0的富水充填材料失稳破坏的临界应力为1.96 MPa,为其单轴抗压强度的90%;蠕变不会对富水充填材料中结合水含量造成影响;富水充填材料失稳破坏时内部结构发生非结合水的流失,非结合水含量损失相对值与所受荷载水平呈线性正相关关系;非结合水的流失导致结构内部出现更多的空隙,这些空隙在外界荷载作用下会迅速被压密,产生较大变形,导致充填体局部失稳,进而影响采空区的整体稳定.

In order to investigate the characteristics of deformation and water loss of hardened paste of water-rich filling material under aging effect,the creep property of water-rich filling materials with a certain mass ratio of water to solid was studied in different stress conditions. The deformation characteristics,water loss and its relationship with external load on the filling body in the process of creep were analyzed by using scanning electron microscopy and differential thermal analysis- thermal gravimetry（ DTA- TG）. It is found that the instability and failure critical stress of water-rich filling materials with a 2. 0 water-to-solid mass ratio is 1. 96 MPa,which is 90% of their compressive strength. Creep cannot affect the content of combined water in water-rich filling materials. But unbound water in water-rich filling materials can run off when instability and failure happen. The relative loss value of unbound water content is of linear positive correlation with the external load level. The loss of unbound water can induce more interspaces in waterrich filling materials. These cracks are quickly pressed and the hardening body produces large deformation under the external load,which leads to the local instability of the filling body and thus affects the overall stability of the goaf.