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陆水坝址的河床上,复盖了7～12米厚的砂砾卵石层,上部为砾质粗砂,厚8米左右;下部为砂夹卵石,厚3米左右。在这种复盖层上,我们在灌浆造孔、压浆混凝土孔柱防渗墙造孔和地下水观测造孔等施工中,先后用孔径为91、108、127、168和219毫米的套管造孔下管13,000余米。施工过程中除了用人工锤击钻进、起重架锤击钻进和震动下管等方法外,还比较成功地试用了风(压缩空气)水辅以人工冲进的方法。这个方法的特点是施工进度快,设备简单,容易掌握。整个施工过程分为定位、冲进和终孔三个阶段。现将施工中摸索到的经验作简要介绍。一、定位与导向造孔前,首先测定孔位。测定工作分单孔和直线排孔两种:在一般灌浆造孔和地下水位观测造孔中都是孤立的单孔,按设计孔位用一般土钻勘探方法定位;防渗墙造孔是孔与孔连成一条直线的排孔,孔位的间距和倾斜度,只要有一个孔不符合要求,对左右邻孔即有影响。同时在造孔过程中,常因正造孔的冲进影响到已造孔的移动,从而除定位外还需要导向和控制偏移。1959年以孔径168毫米的套管造孔时,用三脚架作一个丁字形木夹板将套管夹在中间,左右用与设计孔距同样宽度的铁板钉在木夹
Lu dam site of the riverbed, covering 7 ~ 12 meters thick gravel pebble layer, the upper part of gravel coarse sand, about 8 meters thick; the lower part of the sand pebbles, about 3 meters thick. In this overburden, we grouted hole, grouting concrete hole seepage cut hole and groundwater observation and other construction holes, we have a hole diameter of 91,108,127,168 and 219 mm casing Hole under the tube more than 13,000 meters. In addition to the manual hammering drilling, lifting hammering and vibration under the tube during the construction process, the wind (compressed air) water supplemented by artificial flushing method was successfully tested. This method is characterized by fast construction progress, simple equipment, easy to grasp. The entire construction process is divided into three stages: positioning, punching and final hole. Now the construction of the experience gained a brief introduction. First, the positioning and orientation Before making holes, first determine the hole. Determination of sub-hole and single-hole row of two kinds of work: In general grouting and groundwater table observation hole are isolated single hole, according to the design of the hole with the general method of exploration drilling positioning; cutoff wall hole is the hole And the hole into a straight row of holes, hole spacing and inclination, as long as there is a hole does not meet the requirements of the adjacent holes that have an impact. At the same time in the process of making holes, often due to the impact of the punch is made into the hole has affected the movement, in addition to positioning but also need to guide and control the offset. In 1959 with a hole diameter of 168 mm casing hole, with a tripod for a T-shaped wooden plywood will be caught in the middle of the casing, left and right with the same design pitch pitch iron nails in the wood clip