Diaphragm wall grab is a relatively advanced underground engineering structure form and construction technology.  It uses a special trough-making machine on the ground to excavate along the periphery of the excavation project (such as the side wall of an underground structure) with mud (also known as stabilizing fluid, such as bentonite mud) protecting the wall, forming a certain length of the trench, and then place the prepared steel cage into the trench section, and use the conduit method to pour underwater concrete to form a unit wall section. A specific joint method is used between each wall section (such as using a joint pipe or joints made of joint boxes) are connected to each other to form a continuous underground reinforced concrete wall.  The wall diaphragm grab enclosure structure is closed. After the foundation pit is excavated, the support or anchor system can be added to retain soil and water, which facilitates the construction of the main structure. Currently, wall diaphragm grabs are generally used as building blocks.Diaphragm wall grabs have widely use, mainly used in the basement of buildings, subways, tunnels, docks, water cut walls, retaining walls, etc.