我队地层上部大多为4-6级破碎之大青灰岩,节理极为发育,硬且脆,软硬不均,钻进中易坍塌掉块,岩心不易采取.使用双管钻进(内外管长度差己短至40公厘,再短岩心质量不易保证),虽保证了岩心质量,但回次进尺少,一般只有一米左右,且容易堵 Most of the upper strata in our team are 4-6 large broken green limestones, with extremely developed joints, hard and brittle, hard and soft, easy to collapse when drilling, core difficult to adopt .Double pipe drilling The difference has been as short as 40 mm, and then the quality of the short core is not easy to ensure), although the core quality is guaranteed, but less footage is returned, usually only about one meter, and easy to plug