Technology for building thin concrete underground diaphragm wall with widen type water jetting method

The invention relates to the architectural engineering technical field, providing technique for building a thin wall concrete underground diaphragm wall by a guide enlargement type water injection groove forming method, wherein a guide enlargement type water injection groove forming method is used in the construction of the second-phase groove section; besides a tank, a water inlet pipe, a slag pumping pipe, an injection assembly and a knife assembly which are also adopted in a conventional water injection groove forming machine, the guide enlargement type water injection groove forming machine is characterized by comprising groove enlargement knives and guide blocks arranged on both ends of the tank, wherein two groove enlargement knives and guide blocks on each end form a reverse V shape, and simultaneously transverse nozzles are also arranged; a second-phase groove opening formed is provided with an enlargement end part on the periphery of the first-phase wall section, thereby making the second-phase wall