渣土改良剂对砂土渗透性的改良机制

Improvement Mechanism of Soil Conditioner on Sandy Permeability

摘要: 砂土地层属于典型的力学不稳定地层，其高渗透性带来的喷涌问题是盾构机施工过程中最主要的问题之一，影响盾构机排渣、正常掘进甚至掌子面土压平衡。渣土改良技术对于解决此类问题方便有效，其中最常用的三种改良剂为：泡沫剂、高分子聚合物以及膨润土泥浆。因此，通过对泡沫剂的阻塞作用、黏附作用、时效性，膨润土的级配优化、微观机理，高分子聚合物的微观结构、化学成分展开分析，得到改良剂对砂土渗透性的改良机理，为砂性地层渣土改良奠定了理论基础，对于富水砂层开挖“喷涌”问题来说具有重大意义。

Abstract: The sandy soil layer is a typical mechanically unstable formation. The spouting problem caused by its high permeability is one of the most important problems in the construction of the shield machine, which affects the shield machine’s slag discharge, normal excavation and even the earth pressure balance of the tunnel face. The muck improvement technology is convenient and effective to solve such problems. The three most commonly used modifiers are: foaming agent, polymer and bentonite mud. Therefore, through the blocking effect, adhesion effect and timeliness of the foaming agent, the optimization of the gradation of bentonite, the micro-mechanism, and the analysis of the microstructure and chemical composition of the polymer polymer, the improvement mechanism of the sandy soil permeability of the modifier is obtained. Laid a theoretical foundation for the improvement of sandy strata and muck soil, which is of great significance to the “spraying” problem of water-rich sand excavation.