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华东建设基础总公司在软弱地基处理中应用了投石压浆素砼桩,取得了良好的效果。该方法就是在软弱地基上,根据不同的持力层及下卧层深度,设计一定数量的投石压浆素砼桩(其成桩工艺与导管水下灌注的砼桩是完全不同的)。钻进成孔后,投石压浆工艺不用下导管,而采用下注浆管的办法,自孔口投入粗骨料,再将水泥与细骨料搅拌成的水泥砂浆浆液经灰浆泵送入注水管,由孔底压出,直至充满整个孔内石料的间隙,见孔口冒浆溢出,即可提出注浆管,形成素砼桩体,成桩后实际使用时,将桩顶部敲去50cm以上的松散浮浆层,使其与基桩底部平齐,然后平铺夯实一层碎石褥垫层,使这些桩体与土层共同作用,承受上部荷载,形成复合地基。
The East China Construction Foundation Corporation applied ballast grouting piles to treat soft ground and achieved good results. The method is to design a certain number of rammed pulp rammed piles on the weak foundations according to the different bearing layers and the depth of the underlying layer (the pile forming process is completely different from the ramming piles for underwater pouring of the conduits). After drilling into the hole, the grouting process without throwing down the pipe is adopted, and the method of pouring the slurry into the pipe is adopted. The coarse aggregate is injected into the hole and the slurry of the cement mortar mixed with the fine aggregate is fed into the slurry through a mortar pump. The water pipe is pushed out from the bottom of the hole until it fills the gap of the stone in the whole hole. If the overflow from the hole is seen, the grouting pipe can be put forward to form a pile of primes. When the pile is actually used after being piled, the top of the pile is knocked out to 50cm. The above loose laitance layer is made flush with the bottom of the foundation pile, and then a layer of crushed stone cushion is tiled to make these piles work together with the soil layer to withstand the upper load and form a composite foundation.