泥炭质土中有机质含量对泥浆性能的影响研究

Study on the Effect of Organic Matter Content in Peaty Soilon Mud Performance

钻孔灌注桩在特殊地层施工时,泥浆的性能是维持钻孔稳定的关键因素之一。本研究以云南某房地产项目桩基施工使用泥浆护壁钻孔灌注桩为工程背景,进行室内试验配置,探究不同有机质泥炭质土对护壁泥浆比重、粘度、胶体率、失水率、泥皮厚度、pH值等指标性能的影响。通过试验发现:(1)泥炭质土介质的存在会使得膨润土泥浆产生失水量增大、胶体率降低、泥皮性状变差等不利作用;(2)泥浆“受损”程度受到泥炭质土中的有机质含量的影响,当有机质含量越高时,对护壁泥浆的“不良作用”就越大,使泥浆的各项性能指标发生显著改变;(3)泥炭质土介质下泥浆性能发生改变降低混凝土桩身强度。

Mud performance is one of the key factors to maintain the stability of bored pile in special stratum construction. Based on the construction background of pile foundation in a real estate project in Yunnan Province, this study conducts laboratory test confi guration to explore the ef fects of dif ferent organic peaty soils on the specifi c gravity, viscosity, colloid rate, water loss rate, mud thickness, pH value and other indicators of wall protection mud. The results show that:(1) the adverse ef fects of the presence of peatbased clay medium mainly include the increase of water loss, the decrease of colloidal ratio, and the deterioration of mud properties.(2) The "damage" degree of mud is af fected by the content of organic matter in peaty soil. The higher the content of organic matter is,the greater the "adverse ef fect" on the wall protection mud is, which signifi cantly changes the performance indexes of mud.(3) The strength of concrete pile is reduced by the change of mud performance under peaty soil medium.