【摘要】 针对软土地区深基坑支护的特点,采用一种新型的支护形式——预应力管桩水泥土复合挡墙(PCMW),即在水泥深层搅拌桩的施工过程中插入大直径预应力管桩,从而形成挡土、止水合二为一的连续墙体。与传统的钻孔灌注桩、SMW、地下连续墙等支护形式相比,PCMW具有承载力大、变形小、占用空间少、低污染、施工速度快、节省造价等优点,提高了软土地区深基坑支护的安全性和经济性。介绍了该支护形式在城市隧道支护工程中的应用及现场测试情况。根据实测的水泥土强度、深层土体位移、支撑轴力以及邻近房屋、道路沉降等数据可知,PCMW支护形式用于软土地区深基坑支护是可行的,并且在技术、经济指标上具有较大优势。更多还原

【Abstract】 Considering the characteristics of deep excavation in soft soil,a novel support system is proposed,which is named as PCMW(Prestressed Concrete Tube-pile Soil-cement Mixed Wall).The precast tube pile is plugged into the unset soil-cement mixing piles,and in this way,a diaphragm wall is formed to withstand the soil pressure and keep groundwater from seeping.Compared with the conventional support systems,such as bored piles,SMW and concrete diaphragm wall,etc,PCMW provides higher bearing capacity,smaller deformation,less space occupied,lower environmental pollution and shorter construction period.Therefore,it increases the safety and efficiency of deep excavation support projects.The application of PCMW in a deep city tunnel excavation is presented and the field behaviors are summarized.According to the field test data,including soil-cement strengths,soil deformations,brace loads and adjacent building/road settlement,conclusion can be drawn that the proposed PCMW system is suitable for deep excavation support in soft soil;moreover,it is more competitive in many technical and economical indexes.The applicable scope of PCMW is discussed and other combined forms of PCMW are further presented.更多还原