劈裂式灌浆技术在孤石滩水库闸坝接头段隐患处理中的应用

Application of split grouting to treatment with the hidden troubles of joint segment of sluice and dam of Gushitan Reservoir

针对闸坝接头段粘土心墙质量不合格、存在大量裂缝等问题,拟采用充填式灌浆法进行处理,但充填式灌浆试验结果表明:灌浆压力太小,不能灌进浆液。根据闸坝接头段粘土心墙中有2道刺墙、坝基为红色砂岩、溢洪道左侧闸墙等特殊情况,通过白氏“孔底注浆、全孔灌注”劈裂式灌浆的反复试验,表明在常规灌浆压力条件下,对坝体粘土心墙中下部段亦无法灌进浆液;在加强各项观测工作,严格控制坝顶劈裂缝某点最大宽度,使之等于4cm(规范规定为3cm之内),且回弹比大于80%的条件下,进行了大幅度提高灌浆压力的试验,最终确定中部灌浆段施工灌浆压力为0.15～0.23MPa,下部灌浆段为0.25～0.40MPa。结果表明,灌浆效果很好。其一,灌浆1年半后,所灌浆液充填、固结较好,且与周边土体胶结较好,灌浆后粘土心墙质量有所改善;其二,灌浆后至今7年多,经多次洪水考验,闸坝接头段无异常。

Aimed at special questions that there were many cracks in the joint segment of sluice and dam, in which the quality of clay core was disqualification, the method of filling grouting was planned to adopt. The test results showed that the grouting pressure was too low to grout slurry. Based on special circumstances there were two insert-walls in the clay core, red sandstone bam foundation, sluice-wall in the left of spillway etc., the split grouting that pour grouting at the bottom of bore and perfusion around bore, Bai's method was adopted to treat with these hidden troubles. It showed that the slurry could not be grouted to the middle-inferior part of clay core in routine grouting pressure. By time after time tests, the conditions of split grouting was confirmed, these were the width of split on the top of dam was equal to 4 cm (the criterion ordered 3 cm) and the resilience proportion was larger than 80%, the grouting pressures were 0.15-0.23 MPa and 0.25-0.40 MPa on the middle part and inferior part respectively. The effect of grouting is good. Concretely, inspecting results after grouting 1.5 years, are filling full slurry in dam body, nice concretion and cementation with around the earth of the slurry. The quality of clay core after grouting was improved. Up to the present, over seven years, the joint segment of sluice and dam was all right by time after time floodwaters.