在后张法预应力混凝土施工中,对预留孔道抽芯钢管的接头处理,过去一般采用铁皮套管接头。这种接头存在以下不足:套管和抽芯钢管易被水泥浆粘结或卡死而造成拔管困难;当抽芯钢管需接长而变成“实心管”时,由于在套管处形成真空(低压)带而塌孔。 In the post-tensioned prestressed concrete construction, the joint treatment of the cored steel pipe for reserved holes has been generally used in the past. The joints have the following deficiencies: the casing and core-pulling steel pipes are easily stuck by the cement paste or cause the difficulty of extubation; when the core-plunged steel pipe needs to be lengthened and become a “solid pipe”, it is formed at the casing. Vacuum (low pressure) and hole collapse.