CN211816279U - New and old ground is wall interface processing structure even - Google Patents

Abstract

The utility model discloses a new and old ground connecting wall interface processing structure, which comprises a lengthened underground continuous wall, and relates to the field of foundation pit engineering. It includes the extension underground diaphragm wall, the new underground diaphragm wall and the old underground diaphragm wall; one end of the extension underground diaphragm wall is connected with the new underground diaphragm wall, the other end is in contact with the old underground diaphragm wall, and the extended underground diaphragm wall is connected with the old underground diaphragm wall. A plurality of grouting pipes are arranged at the contact. The utility model builds a lengthened underground continuous wall near the joint of the old and new underground continuous wall, and adds a grouting pipe at the joint, and then performs foundation pit excavation after grouting, and passes through artificially extended bypass channels and grouting. Reinforcement, so as to improve the water-stop effect of joints and ensure the safety of foundation pit excavation construction.

Description

New and old ground-to-wall interface processing structure

technical field

The utility model relates to the field of foundation pit engineering, in particular to a new and old ground connecting wall interface processing structure.

Background technique

According to "Technical Regulations for Building Foundation Pit Support" JGJ120-2012, the definition of foundation pit support is as follows: In order to protect the construction of the main underground structure and the safety of the surrounding environment of the foundation pit, the temporary support, reinforcement and protection of the foundation pit are used. and groundwater control measures. Whether a supporting structure is used in the excavation of the foundation pit, and what kind of supporting structure should be used, should be based on the surrounding environment of the foundation pit, the excavation depth of the foundation pit, the engineering geological and hydrogeological conditions, the construction conditions, the construction season, and the regional engineering experience. The comprehensive analysis of technology and environment is relatively determined. In foundation pit projects with high groundwater level, poor stratum conditions and large excavation depth, supporting structures such as bored cast-in-place piles, underground diaphragm walls, and occlusal cast-in-place piles are often used.

Underground diaphragm wall is a commonly used supporting structure in foundation pit engineering. Under the condition of mud wall protection, a narrow and long deep groove is excavated on the ground. After the groove is cleared, a steel cage is suspended, and the underwater concrete is poured by the pipe method to form A unit trough section, so section by section, builds a continuous reinforced concrete wall underground.

Between each unit groove section, the underwater concrete poured successively forms a water-stop weak zone at the joint. In order to improve the water-stop effect at the joint, various water-stop structures such as locking pipe and I-beam can be used. Before pouring concrete in the first-phase groove section, after setting the lock pipe or joint box, pour the first-phase groove section concrete; An artificially extended bypass channel is formed between the concrete of the second-stage trough section and the first-stage trough section, so as to meet the water-stop requirements.

The above various underground diaphragm wall joint water-stop structures are suitable for new structures that start simultaneously. The length and joint layout of each groove section of the first-phase groove section and the second-phase groove section of the underground diaphragm wall have been determined before construction. Before and after construction The interval time is short, so its seam treatment works well.

With the rapid development of urban underground engineering construction, there are more and more various underground foundation pit projects. The newly built foundation pit project is increasingly restricted by the surrounding environmental factors, and there are more and more cases of close to the original underground foundation pit project construction. In addition, in rail transit projects, the main project is generally started first, and the auxiliary projects (such as wind pavilions, entrances and exits, etc.) are usually started after being restricted by the surrounding environment. The layout plan of the project is uncertain, and the auxiliary projects are all connected to the main project. Therefore, when the groundwater level in the geological environment where the underground project is located is high and the stratum conditions are poor, the supporting structure of the foundation pit mostly adopts the underground diaphragm wall, but due to various factors, the original underground diaphragm wall cannot reserve the interface for the subsequent underground diaphragm wall. Therefore, it is necessary to deal with the joints between the new and old underground diaphragm walls, otherwise, water leakage and sand leakage will easily occur during the excavation of the foundation pit, which will endanger the safety of various surrounding structures and the safety of the foundation pit itself.

For the joint treatment of new and old underground diaphragm walls, currently on the soil-facing side of the joints of the foundation pit, grouting or high-pressure jetting piles are generally used for soil reinforcement. The quality of body reinforcement should not be controlled, and the investment cost is high and unfavorable factors are affected.

Therefore, it is particularly important to develop a new and old ground connecting wall interface treatment structure to deal with the joints between the old and new underground continuous walls when the excavation depth of the foundation pit project is large, the stratum conditions are poor, and the groundwater level is high.

Utility model content

The purpose of the present invention is to provide a new and old ground connection wall interface processing structure in order to overcome the shortcomings of the above-mentioned background technology.

In order to achieve the above object, the technical scheme of the present utility model is:

The interface processing structure of the new and old ground connecting wall is characterized in that: it includes an underground continuous wall of an extended section, a new underground continuous wall and an old underground continuous wall; one end of the underground continuous wall of the extended section is connected with the new underground continuous wall, and the other end is connected with the old underground The diaphragm wall is in contact, and multiple grouting pipes are arranged at the contact between the underground diaphragm wall of the extended section and the old diaphragm wall; The gap between the extended underground diaphragm wall and the old underground diaphragm wall.

In the above technical solution, the new underground diaphragm wall includes a first-stage trough section and a second-stage trough section, and there is a joint water-stop device between the first-stage trough section and the second-stage trough section; Slot segment connection.

In the above technical solution, the plane arrangement spacing between the grouting pipes is 0.5-0.8m.

In the above technical solution, the grouting holes of the grouting pipe are arranged in a plum blossom shape, the diameter of the grouting holes is 10mm, and the distance between the holes is 20-30cm; the length of the upper and lower ends of the grouting pipe without drilling is 0.5-1.5m, as a stopper section.

In the above technical solution, the plane form of the extended underground diaphragm wall and the new underground continuous wall is L-shaped or Z-shaped, and the length of the overlapping section of the extended underground continuous wall and the new underground continuous wall is 2-3m.

In the above technical solution, the length of the underground diaphragm wall, the grouting pipe and the first-stage groove section have the same depth.

The utility model builds a lengthened underground continuous wall near the joint of the old and new underground continuous wall, and adds a grouting pipe at the joint, and then performs foundation pit excavation after grouting, and passes through artificially extended bypass channels and grouting. Reinforcement, so as to improve the water-stop effect of joints and ensure the safety of foundation pit excavation construction.

Description of drawings

FIG. 1 is a schematic structural diagram 1 of the present utility model.

FIG. 2 is a schematic structural diagram 2 of the utility model.

FIG. 3 is a schematic structural diagram of the utility model when the joint water-stopping device is a joint pipe.

4 is a schematic structural diagram of the utility model when the joint water-stopping device is an I-beam.

Among them, 1-extended underground diaphragm wall, 2-new underground diaphragm wall, 21-first-phase trough section, 22-second-phase trough section, 23-joint water stop device, 3-old underground diaphragm wall, 41-affiliated foundation Pit, 42-Main foundation pit.

Detailed ways

The implementation of the present utility model will be described in detail below with reference to the accompanying drawings, but they do not constitute a limitation to the present utility model, but only serve as examples. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

Referring to the accompanying drawings, it can be seen that the interface processing structure of the new and old ground connecting walls is characterized in that: it includes an underground continuous wall 1 of an extended section, a new underground continuous wall 2 and an old underground continuous wall 3; one end of the underground continuous wall 1 of the extended section is connected to the new underground The diaphragm wall 2 is connected, and the other end is in contact with the old underground diaphragm wall 3. A plurality of grouting pipes 11 are arranged at the contact between the underground diaphragm wall 1 of the extended section and the old underground diaphragm wall 3; by grouting the grouting pipes 11, filling The gap between the new underground continuous wall 2 and the old underground continuous wall 3 is filled with the gap between the extended underground continuous wall 1 and the old underground continuous wall 3 .

The new underground diaphragm wall 2 includes a first-stage trough section 21 and a second-stage trough section 21, and there is a joint water-stop device 23 between the first-stage trough section 21 and the second-stage trough section 21; The first-stage groove section 21 is connected.

The plane arrangement spacing between the grouting pipes 11 is 0.5-0.8m.

The grouting holes of the grouting pipe 11 are arranged in a plum blossom shape, the grouting hole diameter is 10mm, and the hole spacing is 20-30cm; .

The plane forms of the extended underground diaphragm wall 1 and the new underground diaphragm wall 2 are L-shaped or Z-shaped, and the specific plane form can be adjusted in time according to the layout of the main foundation pit 42; the extended underground diaphragm wall 1 and the new underground continuous wall The length of the overlapping section of wall 2 is 2-3m.

The length of the underground diaphragm wall 1, the grouting pipe 11 and the first-stage groove section 21 are the same in depth, and the specific depth requirements are determined according to the requirements of the auxiliary foundation pit 41.

The new and old ground connection wall interface processing method is characterized in that, comprises the following steps:

Step 1: After the processing is completed, the multiple grouting pipes 11 are firmly bound with the reinforcing cage of the underground diaphragm wall 1 in the extended section, and the sections are numbered after the acceptance is passed;

Step 2, the extended section underground diaphragm wall 1 and the first-phase groove section 21 of the new underground diaphragm wall 2 are synchronously formed into grooves and synchronously poured;

Step 3: After the underground diaphragm wall 1 of the extended section reaches the design strength, before the excavation of the auxiliary foundation pit 41 (new foundation pit), grouting is carried out on the ground through the grouting pipe 11; In order to improve the grouting quality;

Step 4: After the grouting is completed, the grouting hole of the grouting pipe 11 is pressure-sealed with cement slurry.

In actual use, the technical parameters of the lengthened underground diaphragm wall 1 into a groove:

1) During the excavation process of the trench section adjacent to the main foundation pit 42 (original foundation pit), the trench should always be filled with mud to keep the trench wall stable;

2) The observation of stability should be strengthened during the excavation of the trench section. If the trench wall has serious local collapse, it should be backfilled in time and properly handled;

3) The mud leakage during construction should be replenished in time, and the necessary liquid level should always be maintained. Regularly check the mud quality and adjust the mud index in time;

4) After the excavation of the groove section is completed, the groove position, groove depth, groove width and verticality of the groove wall should be checked.

5) The control of the final groove depth of the groove section should meet the following requirements: a. The final groove depth of the groove section must ensure the design depth. In the same groove section, the excavation depth of the bottom of the groove should be consistent and flat; b. The extended section in the same groove section is underground The groove bottom of the diaphragm wall 1 should be consistent with the excavation depth of the groove bottom of the first-stage groove section 21;

6) The length, thickness and inclination of the groove section should meet the following requirements: a. The allowable deviation of the length of the groove section is ±2.0%; b. The allowable deviation of the thickness of the groove section is ±10mm; c. The allowable deviation of the verticality of the groove section is ±1/300 ;d. The partial protrusion of the wall should not be greater than 100mm; e. The position deviation of the embedded parts on the wall should not be greater than 100mm; f. The deviation of the center line of the wall top: ≤30mm; g. The area of holes, exposed ribs and honeycombs should not be More than 5% of the exposed area of the unit groove section; h. There is no mud and water leakage at the joints of the groove section;

7) After digging the tank, the sediment and other debris at the bottom of the tank should be cleaned up. One hour after the bottom of the tank is cleaned and replaced with mud, the specific gravity of the mud within 500mm of the bottom of the tank should not be greater than 1.15, and the thickness of the sediment should not be greater than 100mm.

Grouting pipe 11 technical parameters

42袖阀管，注浆液采用水泥浆液，浆液比例为0.5:1，水泥等级不低于42.5级；1) The grouting pipe 11 adopts

42 sleeve valve pipe, the grouting liquid is cement grout, the grout ratio is 0.5:1, and the cement grade is not lower than 42.5;

2) Grouting pressure 0.15-0.2MPa;

3) The grouting pipe 11 should extend into the bottom of the hole, and the grouting section can be 0.3-0.5m according to different formations;

4) The slurry diffusion radius should be determined according to the field grouting test, but should not be less than 250mm;

5) The grouting can be terminated when one of the following conditions is met: a. The grouting amount (0.5m ³ per linear meter) and the grouting pressure (0.2MPa) meet the design requirements; b. The grouting amount has reached 75% of the design value %, and the grouting pressure exceeds the design value;

6) After grouting, use 0.5:1 cement slurry to seal the grouting hole under pressure.

Other unexplained parts belong to the prior art.

Claims (6)

1. The interface processing structure of the new and old ground connecting wall is characterized in that: it comprises an underground continuous wall (1) of an extended section, a new underground continuous wall (2) and an old underground continuous wall (3); the underground continuous wall of the extended section (1) ) is connected with the new underground diaphragm wall (2) at one end, and the other end is in contact with the old underground diaphragm wall (3). Multiple grouting pipes ( 11); by grouting the grouting pipe (11), the gap between the new underground diaphragm wall (2) and the old underground diaphragm wall (3) is filled, and the extended underground diaphragm wall (1) is continuous with the old underground wall. Gap between walls (3). 2. The new and old ground connecting wall interface processing structure according to claim 1, characterized in that: the new underground continuous wall (2) comprises a first-stage groove section (21) and a second-stage groove section (22), and the first-stage groove section (22) A joint water stop device (23) is arranged between the trough section (21) and the second-stage trough section (22); the underground continuous wall (1) of the extended section is connected with the first-stage trough section (21). 3. The new and old ground connecting wall interface treatment structure according to claim 1 or 2, characterized in that: the plane arrangement spacing between the grouting pipes (11) is 0.5-0.8m. 4. The new and old ground connecting wall interface treatment structure according to claim 3, characterized in that: the grouting holes of the grouting pipe (11) are arranged in a plum blossom shape, the grouting hole diameter is 10mm, and the hole spacing is 20-30cm ; The length of the upper and lower ends of the grouting pipe (11) without drilling is 0.5-1.5m, as the grouting stop section. 5. The new and old ground connecting wall interface treatment structure according to claim 4, characterized in that: the plane forms of the extended underground continuous wall (1) and the new underground continuous wall (2) are L-shaped or Z-shaped, The length of the overlapping section of the extended underground diaphragm wall (1) and the new underground diaphragm wall (2) is 2-3m. 6 . The new and old ground connecting wall interface treatment structure according to claim 5 , wherein the length of the underground continuous wall ( 1 ), the grouting pipe ( 11 ) and the first-stage groove section ( 21 ) have the same depth. 7 .

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