Anti-break grouting drill rod for overlying strata separation layer grouting settlement reduction

An anti-break grouting drill rod for overlying strata separation layer grouting settlement reduction comprises a main drill rod body connected with an external drilling machine and an extension drill rod body stretching into the bottom of a grouting drill hole, a connecting pipe is arranged between the main drill rod body and the extension drill rod body, the bottom end of the connecting pipe is fixedly connected with the top end of the extension drill rod body, and the top end of the connecting pipe can be connected with and separated from the bottom end of the main drill rod body. When the main drill rod is separated from the connecting pipe, the bottom end of the main drill rod is located in the connecting pipe, and a movable gap is formed between the bottom end and the inner side wall of the connecting pipe. According to the device, in the overlying strata separation layer grouting process, the situation that the grouting drill rod is broken due to the fact that the grouting drill rod is affected by rock