注气增压作用下的软土排水增效机理试验研究

Experimental Study on Drainage Efficiency Enhancement Mechanism of Soft Soil Under Air-injection Pressurization

通过重塑土的一维物理试验研究了软土注气增压排水效果的内在机理。试验系统包括增压装置、软土压密(劈裂)观测装置、排水量测量装置等。随后观测了软土沉降、排水过程及裂隙发育特征。结果表明:压力气体通过孔隙水的驱替与孔隙的弹塑性扩张实现土体排水压密与劈裂,同时结合表层土体的明显薄弱特征(或裂隙)、平整密实程度,可将注气增压作用下的软土排水增效机理分为排水且劈裂、排水并压密与排水且贯通3种排水增效机制。

In this paper,we investigate the inherent mechanism of the drainage effect of soft soil under airinjection pressurization through one-dimensional physical tests on the remolded soil.The experimental system includes pressurization devices,soft soil compaction(fracture)observation devices,drainage measurement devices,etc.Then,we observe the settlement of the soft soil,the drainage process,and the crack development characteristics.The results show that the pressure gas achieves the drainage compaction and fracturing of the soil by displacing the pore water and elastically expanding the pores.Combined with the obvious weak characteristics(or cracks)and the degree of surface soil compaction,the drainage enhancement mechanisms of soft soil under air injection pressurization can be divided into three types:drainage with fracturing,drainage with compaction,and drainage with permeability.