吹填土地区钻孔灌注桩施工质量控制浅析

A Simple Explanation on Bored Pile Construction Quality Control in Hydraulic Filled Land

吹填土是填海造陆的产物,吹填土地区钻孔灌注桩施工过程中的质量控制,是桩基施工领域的难点之一,其中主要包括泥浆制备、成孔、清孔、混凝土灌注等施工工序的质量控制。在吹填土地区施工钻孔灌注桩,首先应根据场地的地质勘察资料以及试验确定合理的泥浆密度,防止泥浆密度不足或泥浆过稠;在成孔过程中,应采取隔孔施工顺序,并加强对桩身成孔垂直度的控制,防止出现塌孔、缩孔、桩孔偏斜及桩端达不到设计持力层要求,并采取各种措施保证孔径达到设计要求;为获得较好灌注质量,应采取大体积混凝土冲击灌注方法,并控制坍落度为180～220mm,超灌高度为500mm以上,充盈系数要求大于1。

The hydraulic filled land is a result of reclamation engineering, bored pile construction quality control in hydraulic filled land is one of nodi in pile foundation construction, thereinto include quality control in drilling mud preparation, borehole construction, cleaning, and concrete grouting operations. During the bored pile construction in hydraulic filled land, rational mud density should be determined based on site geological exploration data and laboratory tests to prevent insufficient or too thick of mud density. During the borehole construction, alternating drilling sequence has adopted and pile verticality control strengthened, to prevent pile hole collapse, shrinkage, deflection and pile tip cannot reach the designed bearing stratum, and a variety measures adopted to ensure hole diameter accord with designed requirements. To obtain better grouting quality, method of bulk mass concrete driven cast-in-place should be adopted, with slump 180-220mm, exceed grouting height 500mm above, fullness coefficient 〉1 controlled.