我队某地区为泥土礫石层,以跟管法不易开井,往往造成井故。曾用150合金鑽头鑽进下大管,稍一提起,井壁就坍下;採用130小徑透、150大徑扩下大管也未成功。为此,採用了挖井跟管法,取得了好的效果。挖井跟管法如图1示意图所示,是一种在礫石层开井下大管的办法。首先按地质设计孔位,挖一长1.5米、寬1.5米、深4米小井,井壁以支架支好,防止坍下,如小井內有水,以人力抽水器抽出。挖好井后再舖机台枕按装机械。开孔前先把长4.2米 Some areas of our team for the gravel layer of mud, with the law is not easy to open wells, often resulting in well. 150 alloy drill has been used to drill into the next big pipe, a little mention, the wall collapsed; the use of 130 small diameter, 150 large diameter expansion of large pipe failed. To this end, the use of digging well with the law, and achieved good results. Well digging with the tube method shown in Figure 1 is a schematic diagram, is a gravel layer open underground pipe approach. First of all, according to the geological design of holes, dig a 1.5 m long, 1.5 m wide and 4 m deep. The well wall is supported by brackets so as to prevent collapse. If there is water in the well, it is drawn out by a human water pump. After digging a well and then shop machine pillow installed machinery. 4.2 meters long before opening a hole