CN103122642B - Construction method of vertical post support change - Google Patents

Abstract

The invention particularly relates to a construction method of vertical post support change. The construction method of the vertical post support change is adopted in a dry dock foundation pit supporting structure used for prefabricating immersed tube joints. An underground diaphragm wall shaped like a Chinese charter 'ji' is adopted as a supporting structure of a dry dock foundation pit, a horizontal supporting body is arranged on the top of the underground diaphragm wall shaped like the Chinese charter 'ji', a vertical latticed column is arranged in the middle of the horizontal supporting body, and after an immersed tube joint is fabricated, a vertical post support change body is arranged on the top of the immersed tube joint, and the portion of the vertical latticed column, above a dry dock foundation pit base board, is cut off. After the dry dock foundation pit is filled with water and the water level meets the floating water level of the immersed tube joint, the horizontal supporting body and the vertical post support change body are removed, and now pressure generated by water on the diaphragm wall is utilized to replace supporting force of the removed horizontal supporting body. The construction method of the vertical post support change has the advantages of reducing the mass size of underground diaphragm wall construction members, reducing construction cost and effectively controlling occupied area of the underground diaphragm wall, and meanwhile the construction method of the vertical post support change does not influence construction quality of the immersed tube joints and floating undock.

Description

A Construction Method for Replacing a Vertical Pillar

technical field

The invention belongs to the field of immersed tube tunnel construction, and in particular relates to a construction method for replacing vertical pillars used in a dry dock foundation pit support structure for prefabricated immersed tube joints.

Background technique

Underwater tunnels have become an important node project in the planning network of transportation facilities. Nearly hundreds of underwater transportation tunnels have been built all over the world, and more than 100 tunnels are built using the immersed tube method. In the construction of immersed tube tunnels, its dry dock, pipe section, foundation trench, pipe section foundation, etc. are the main sub-projects of immersed tube tunnels. The dry dock is responsible for the prefabrication and floating tasks of immersed tube sections, and plays an important role in immersed tube tunnels.

In the case of a small site, the common method of dry dock construction is as follows: set up a cantilever type "Π" type or lattice structure underground diaphragm wall, and generally do not set horizontal supports in order to consider the floating of immersed tube joints. This method is more convenient for the fabrication of immersed tube joints and lifting and undocking, but the section required for the cantilevered “Π” type or lattice underground diaphragm wall to meet the water and soil pressure outside the foundation pit is relatively large, resulting in the volume of the surrounding wall. If it is too large, the cost of the dry dock will be higher and the floor space will increase.

Contents of the invention

The purpose of the present invention is to provide a construction method for vertical pillar replacement according to the deficiencies of the above-mentioned prior art. Lattice columns and vertical pillars are replaced as the supporting structure to reduce the section and volume space dimensions of the underground diaphragm wall support structure.

The object of the present invention is realized by the following technical solutions:

A construction method for vertical pillar replacement, involving a dry dock foundation pit, immersed tube joints built in the dry dock foundation pit, and a "Π" type underground diaphragm wall as the support structure of the dry dock foundation pit, It is characterized in that the construction method includes at least the following steps: setting a horizontal support on the top of the "Π" type underground diaphragm wall, setting a vertical lattice column near the middle of the horizontal support, and the vertical lattice column The bottom goes deep into the soil at the bottom of the dry dock foundation pit, which is used as a temporary support structure for the horizontal support; the immersed tube joint is made; and then vertical pillars are set on the top of the immersed tube joint for support, The two ends of the vertical support support are respectively supported and connected to the horizontal support and the immersed tube joint, which are used as the vertical support structure of the horizontal support; after that, the vertical lattice column is cut off The part above the bottom plate of the dry dock foundation pit; set a water tank in the immersed pipe joint and add water pressure to open the dock mouth of the dry dock foundation pit to pour water into the dry dock foundation pit; When the water level in the dock foundation pit reaches the height of the buoy, remove the horizontal support and replace the vertical support, drain the water in the water tank, and float the immersed tube joint.

The support connection is: pre-embed a reinforcement cage at the support position of the horizontal support, and the reinforcement cage is protruding from the lower surface of the horizontal support; a reinforcement cage is preset in a casing, and then the The casing is arranged at the support connection; the pre-embedded reinforcement cage and the preset reinforcement cage are connected, and finally the filling and grouting of the reinforcement cage is completed to form the support connection for the replacement of the vertical pillar.

An enlarged foundation is provided at the bottom of the vertical support brace, and an isolation layer is arranged between the enlarged foundation and the top plate of the immersed tube joint.

The vertical support is a steel member, the bottom of which is connected to the top of the immersed tube joint by bolts, and the top is connected to the horizontal support by hoops.

The advantage of the present invention is that by setting the horizontal support on the underground continuous wall of the foundation pit of the dry dock, and successively replacing the vertical lattice column and the vertical support as its supporting structure, the volume of the underground continuous wall component is reduced The size not only reduces the project cost and effectively controls the area occupied by the underground diaphragm wall, but also has no impact on the construction quality of the immersed tube joints and the lifting and undocking. It is especially suitable for the construction of dry dock foundation pits under narrow conditions.

Description of drawings

Fig. 1 is the schematic diagram that horizontal support and vertical lattice column are set for construction step one among the present invention;

Fig. 2 is the construction steps 2 and 3 in the present invention, promptly arranges the schematic diagram of the vertical pillar changing support at the top of the immersed tube joint;

Fig. 3 is the schematic diagram that the construction step 4 among the present invention cuts off the vertical lattice column;

Fig. 4 is the construction step five in the present invention namely the schematic diagram that water tank is set in the immersed tube section;

Fig. 5 is the schematic diagram of pouring water in the dry dock foundation pit after first adding water pressure in the water tank in construction step five among the present invention;

Fig. 6 is the schematic diagram that the construction step 6 among the present invention promptly dismantles horizontal support and vertical pillar and changes support;

Fig. 7 is a schematic diagram of pumping the water body in the drainage tank to float the immersed tube joint in the sixth construction step of the present invention;

Fig. 8 is a partially enlarged view B of vertical pillar replacement in the present invention;

Fig. 9 is the plane view A-A of the "Π" type underground diaphragm wall in the present invention.

Detailed ways

The features of the present invention and other relevant features are described in further detail below in conjunction with the accompanying drawings through the embodiments, so as to facilitate the understanding of those skilled in the art:

As shown in Figure 1-9, the marks 1-7 in the figure are: horizontal support 1, steel cage 1-1, vibrating hole 1-2, underground diaphragm wall 2, vertical lattice column 3, vertical lattice column pile Foundation 3-1, immersed tube joint 4, reserved hole 4-1, vertical pillar support 5, casing 5-1, steel cage 5-2, enlarged foundation 5-3, water tank 6, isolation layer 7.

Embodiment 1: This embodiment relates to a construction method using vertical pillar replacement in the dry dock foundation pit of an immersed tube tunnel. By using horizontal support and vertical pillar replacement as the supporting components of the dry dock foundation pit, the The volume size and engineering cost of the support structure (i.e. the underground diaphragm wall) in the foundation pit of the small dry dock, the construction method includes the following steps:

①As shown in Figures 1, 8 and 9, a "Π" type underground diaphragm wall 2 is set in the dry dock foundation pit, and a horizontal support 1 is arranged on the top of the underground diaphragm wall 2, and the horizontal support 1 is used to support the underground diaphragm wall. 2 provide lateral supporting force, and at the same time, set a vertical lattice column 3 near the center of the horizontal support 1, and the bottom of the vertical lattice column 3 goes deep into the bottom soil of the dry dock foundation pit (that is, the vertical lattice column pile foundation 3-1), the vertical lattice column 3 is used as a temporary support structure for the horizontal support 1; a reinforcement cage 1-1 is pre-embedded at the support connection of the horizontal support 1, and the reinforcement cage 1-1 It protrudes outward from the lower surface of the horizontal support 1, and a vibrating hole 1-2 for pouring concrete slurry is reserved at the center thereof;

②As shown in Figure 1, the immersed tube joint 4 is made afterwards, and a reserved hole 4-1 is set on its bottom plate for the vertical lattice column 3 to pass through;

③As shown in Figures 2 and 8, the reinforced concrete vertical pillar replacement support 5 is applied on the top plate of the immersed tube joint 4, and the construction steps are as follows: a reinforcement cage 5-1 is preset in a circular casing 5-1 2. After that, connect the top of the circular casing 5-1 with the reinforcement cage 1-1 in the horizontal support 1, set an enlarged foundation 5-3 at the bottom of the circular casing 5-1, and at the same time place the immersed tube joint 4 An isolation layer is set between the top plate and the enlarged foundation 5-3, and then concrete slurry is poured into the circular casing through the vibrating holes 1-2 reserved in the horizontal support 1 to form the above-mentioned reinforced concrete vertical pillar replacement. support 5;

④ As shown in Fig. 3, after the strength maintenance of the vertical column support 5 meets the requirements, the upper half of the vertical lattice column 3 is cut off, that is, the part above the bottom of the foundation pit of the dry dock is cut off, and only the part located in the soil is kept. The vertical lattice column pile foundation 3-1 below the body; then clean up and restore the dry dock foundation pit foundation and floor, and then bind the steel bars and pour concrete to seal and fill the reserved hole 4-1 on the bottom plate of the immersed pipe joint 4;

⑤ As shown in Figures 4 and 5, set water tanks 6 on both sides of the immersed tube joint 4 and add water pressure, and then open the dock mouth of the dry dock foundation pit to pour water into the dry dock foundation pit;

⑥ As shown in Figures 6 and 7, when the water level in the foundation pit of the dry dock reaches the buoyancy height of the immersed tube joint 4, the horizontal support 1 and the vertical support 5 used to support the horizontal support 1 are removed and the support 5 is replaced. The pressure generated by the water body on the underground diaphragm wall 2 replaces the support force of the dismantled horizontal support 1 on the underground diaphragm wall 2, and then the water body in the drainage tank 6 is pumped to make the working conditions in the foundation pit of the dry dock meet the requirements of the immersed pipe joint 4 to float out of the dock and other construction conditions.

Embodiment 2: The specific construction method of the vertical pillar replacement in this embodiment is the same as that in Embodiment 1, but in this embodiment, the vertical pillar replacement 5 adopts steel members, and its lower part adopts bolts and immersed tube joints 4. The top plate is connected, and its upper part is connected with the horizontal support 1 by using steel hoops. The use of bolts and steel hoops can facilitate rapid construction and avoid the disadvantages of the maintenance period of the reinforced concrete structure in Embodiment 1. The vertical Changing support 5 to pillar can be removed after pouring water in the dry dock foundation pit.

Claims (4)

1. the construction method of a vertical pillar support replacement, the immersed tube tube coupling that relates to dry-docking foundation ditch, build in described dry-docking foundation ditch and as " Π " type diaphragm wall of described dry-docking foundation pit supporting construction, it is characterized in that described construction method at least comprises the steps:, at described " Π " type diaphragm wall top, horizontal support is set, at the middle part near described horizontal support, vertical lattice column is set, the bottom of described vertical lattice column is deeply to the described dry-docking foundation ditch bottom soil body, in order to the temporary support structure as described horizontal support; Make described immersed tube tube coupling; Vertical pillar support replacement is set at the top of described immersed tube tube coupling afterwards, and the both ends difference support and connection of described vertical pillar support replacement are in described horizontal support and described immersed tube tube coupling, in order to the vertical supporting structure as described horizontal support; Cut off afterwards described vertical lattice column and be positioned at the above part of described dry-docking base plate of foundation pit; In described immersed tube tube coupling, water tank is set and the ballast that adds water, opens the dock entrance of described dry-docking foundation ditch to pour water in described dry-docking foundation ditch; When water level reaches floating absolute altitude in described dry-docking foundation ditch, remove described horizontal support and vertical pillar support replacement, the water body described in pump drainage in water tank, makes described immersed tube tube coupling floating.

2. the construction method of a kind of vertical pillar support replacement according to claim 1, is characterized in that described support and connection are: at the Support Position place of described horizontal support embedded bar cage, described reinforcing cage evagination is in the soffit of described horizontal support; In a casing, default reinforcing cage, is arranged at described support and connection place by described casing afterwards; Connect described embedded bar cage and default reinforcing cage, finally complete the perfusion slip casting of reinforcing cage, to form the described support and connection of described vertical pillar support replacement.

3. the construction method of a kind of vertical pillar support replacement according to claim 1, is characterized in that described vertical pillar support replacement bottom is provided with expansion basis, and described expansion between basis and the top board of described immersed tube tube coupling, a separation layer is set.

4. the construction method of a kind of vertical pillar support replacement according to claim 1, it is characterized in that described vertical pillar support replacement is a steel member, its bottom is by adopting bolt to be connected with the top of described immersed tube tube coupling, and its top is by adopting anchor ear to be connected with described horizontal support.