Impermeable drainage construction method for complex soft rock tunnel

The invention provides an anti-seepage drainage construction method for a complex soft rock tunnel. The construction method comprises the following steps: step 1, geological survey; 2, tunnel excavation construction is carried out; 3, monitoring and measurement are conducted, specifically, dynamic monitoring and measurement are conducted on the tunnel surrounding rock, and related data of ground surface settlement, in-tunnel vault settlement, arch foot settlement and periphery convergence are collected; 4, advanced geological forecasting: advanced forecasting is carried out on surrounding rock and stratum conditions in front of and around the tunnel face by adopting an advanced drilling method; 5, well point dewatering is conducted, specifically, well point pipes directly inserted into the water storage layer are buried around the foundation pit, and underground water is continuously pumped out through the well point pipes through water pumping equipment till the underground water level is lowered to the posi