What is the function of the joint pipe in the diaphragm wall in the ground?

1. Underground diaphragm wall.

The function of the joint pipe is to make the two adjacent groove ends more perfect, without water seepage, for the diaphragm wall reinforcement cage.

and ensure that the concrete turbulence is well controlled.

2. The biggest advantage of the underground diaphragm wall is that in the case of not very complex stratum conditions, it can achieve the integration of three walls, as well as anti-seepage, support and soil retaining. However, the thickness of the wall should be fully demonstrated in the design, and the thickness will generally be greater than or equal to 600mm.

3. The lock pipe is a connection form between the two wall widths when the foundation pit enclosure structure adopts the underground continuous wall. The locking pipe is a flexible connection; There are also rigid connections, such as I-beams.

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329 Animation of the construction of underground diaphragm wall, the role of the joint pipe.

There are flexible joints, rigid joints, perforated steel plate joints, rebar lap joints, rigid joints, and structural joints that are not completely rigid.

Flexible joints: round core lock pipe fittings, corrugated pipe (double wave, triple wave) fittings, prefabricated fittings and rubber waterstop fittings. The underground diaphragm wall structure with poor shear resistance and bending resistance, generally does not need to be the main structure, and the underground diaphragm wall is only used as the basement exterior wall, and does not bear the vertical load of the superstructure or the load is small, and flexible joints can be used by taking some structural measures.

Rigid joints: perforated steel plate and rebar lap joints.

Perforated steel plate joint: It is widely used in the project, and the joint can withstand the shear force on the vertical joint of the underground continuous beam, so that the adjacent underground continuous wall groove section can jointly bear the vertical load of the superstructure, coordinate the uneven settlement of the groove section, and the perforated steel plate joint has good waterproofness.

Reinforcing bar lap joint: using adjacent stage groove section horizontal steel bar concave and convex lap, first construction groove section steel cage on both sides of the lap part, through the construction measures to do it, when cast-in-situ concrete can leave the space of the steel bar lap part, first groove section pouring, then joint steel bar lap, after groove section pouring.

Rigid joint: If the underground diaphragm wall and the structural plate jointly bear a large bending moment at the joint, and the bending stiffness of the two components is similar, and the plate thickness is sufficient to allow the reinforcement to ensure the rigid connection, the rigid connection is used. The common ones are embedded rebar connector connections (cone threads, straight threads) and embedded rebar posture connections.

The structural floor and the underground continuous beam are usually connected by steel bars.

Structural joint is not completely rigidly connected: the thickness of the structural plate is small relative to the underground diaphragm wall, and a certain number of steel bars can be arranged in the plate to bear a certain bending moment, but the steel bars in the plate cannot be configured a lot to form a rigid joint, and it is advisable to adopt the form of incomplete rigid joint.

Answer]: Trapped hole C

The joint pipe (also known as lock E1 pipe) joint is the most used joint in the construction of underground diaphragm wall. During construction, when the earthwork of a unit groove section is excavated, the joint pipe is put into the joint pipe with a crane at the end of the groove section, and then the pin reinforcement cage is hoisted and the Wang imitation dry concrete is poured. After the joint pipe is pulled out, the end of the groove section of the Danian unit forms a semicircle, and the joint of two adjacent groove sections is formed when the construction continues.