目前,国内利用回旋钻机作为桩基础的成孔钻机,应用甚广。成孔后的混凝土灌注桩支承在预期的持力层上,它具有设备简单,施工方便,无噪音,无振动等优点。而利用普通岩心钻机进行适当改装,则更为经济,轻便,一般施工单位都有条件办到。 根据爆扩桩能增大承载力的同样原理,参照国内外技术资料,我们自行设计了一种简易的扩孔钻头,经初步试验,在粘土层,强风化层等持力层,用“扩大头桩”;在松 At present, domestic drilling rigs using rotary drilling rigs as pile foundations are widely used. After the hole is formed, the concrete cast-in-place pile is supported on the expected bearing layer. It has the advantages of simple equipment, convenient construction, no noise and no vibration. The use of ordinary core drilling rigs for proper modification is more economical and portable, and the general construction unit has conditions to do. According to the same principle that the explosion-expanded pile can increase the bearing capacity, referring to domestic and foreign technical data, we have designed a simple reaming drill bit. After preliminary tests, in the clay layer, strong weathering layer and other supporting layers, we use “enlarged Head pile"; in the pine