马钢公司某高炉矿槽长１１１ｍ，宽２０ｍ，高２８ｍ，基础为人工挖孔灌注桩，上部为钢筋混凝土框架结构，拆模后发现③－⑦轴漏斗竖壁下框架柱产生夹层现象（图１），经实测，柱夹层以上部位框架柱的混凝土仅达设计强度的５８％－９５％，是一次较严重的质量事故。１事故原因 Masteel’s blast furnace pit is 111m long, 20m wide and 28m high. The foundation is a manual digging pile, and the upper part is a reinforced concrete frame structure. After demoulding, it is found that the 3-7 axis funnel forms a sandwich phenomenon under the vertical wall of the vertical wall (Figure 1) According to actual measurement, the concrete of the frame column above the column sandwich is only 58% to 95% of the design strength, which is a serious quality accident. 1 The cause of the accident