CN207878451U - A kind of device using hole rising pouring slurry ground-connecting-wall control influence of foundation excavation - Google Patents

Abstract

The utility model discloses a device for controlling the influence of excavation of a foundation pit by adopting a ground connection wall grouted at the bottom of the pit, which comprises a ground connection wall arranged between the area to be constructed and the soil body in the protection area, and a plurality of ground connection walls are arranged in the ground connection wall. Inclinometer pipe, the upper part of the ground connection wall located on one side of the area to be constructed is provided with multiple horizontal supports and multiple grouting pipes, the position of the multiple grouting pipes in the length direction of the ground connection wall is related to the multiple inclinometers The positions of the tubes correspond one-to-one. The traditional servo control of supporting axial force can only control the deformation of the enclosure structure above the excavation surface, and lacks effective control of the deformation of the enclosure structure below the excavation surface. , grouting while excavating, so that the ground connection wall can provide passive side balance pressure with grouting under the condition of small deformation, so as to realize the stress control of the passive area in the foundation pit, so as to ensure the protection structure of the pit bottom during each excavation The deformation is effectively controlled, the operation is convenient and the cost is low.

Description

A device for controlling the influence of foundation pit excavation by using the grouting ground connection wall at the bottom of the pit

technical field

The utility model relates to the technical field of foundation pit engineering construction, in particular to a device for controlling the influence of foundation pit excavation by using a grouting ground connection wall at the bottom of the pit.

Background technique

With the rapid development of the city, more and more urban underground tunnels are put into operation, coupled with the shortage of urban land, the environmental conditions around the foundation pit become more and more complex, and the unloading of deep and large foundation pits will affect the displacement field and the surrounding environment. The facilities have adverse effects, and the deformation control standards for the impact of foundation pits on the surrounding environment are becoming increasingly stringent. The impact of foundation pits on the surrounding environment and deformation control has been developed from centimeter-level deformation control requirements for adjacent existing buildings, roads, underground pipelines, overpasses, etc., to millimeter-level deformation control requirements for adjacent operating subways, high-speed rail, airports, etc. , especially the deep foundation pit poses challenges to the deformation control theory, method and technology of foundation pit engineering. The servo control of the supporting axial force is a common method to control the deformation of the enclosure structure of the foundation pit, but the servo control of the supporting axial force can only control the deformation of the enclosure structure above the excavation surface, and it can control the deformation of the enclosure structure below the excavation surface. Lack of effective control. For foundation pits with supports, the maximum displacement of the foundation pit enclosure usually occurs under the last support, no matter during each step of excavation or when the final excavation is completed. Therefore, when adjacent structures such as tunnels are located below the excavation surface, the servo control of the supporting axial force lacks direct and effective control over the deformation of the enclosure structure at the bottom of the foundation pit.

At present, the servo control of the supporting axial force is often not effective and economical in correcting the deformation and deviation of the surrounding soil around the foundation pit enclosure structure, and the main defects are as follows:

First, the current servo control of the supporting axial force can only control the deformation of the enclosure structure above the excavation surface, and lacks effective control over the deformation of the enclosure structure below the excavation surface.

Second, it is difficult to accurately, timely and flexibly control and pressure-compensate the deformation of the enclosure structure during the excavation process of the foundation pit by the servo control of the supporting axial force.

Therefore, the development of a device that can control the soil deformation of the enclosure structure and can perform pressure compensation accurately, timely and flexibly during the excavation process is an urgent demand for the current market development.

Utility model content

The utility model adopts the dynamic grouting of the ground connection wall at the bottom of the pit to realize the stress control of the ground passive area at the bottom of the foundation pit, so that the ground connection wall can provide the balance pressure of the passive side soil by grouting when the deformation of the ground connection wall is small. When excavating a foundation pit in the soil where the ground connection wall is buried, excavate in layers. Before excavation, the inclinometer pipe is buried in the ground connection wall. During the excavation of the foundation pit, grouting is carried out at the prefabricated grouting point at the bottom of the pit, and the grouting is used to provide balanced pressure to the passive side of the bottom of the foundation pit. The body strain is used to control the deformation of the bottom of the foundation pit to meet the requirements.

In order to solve the above-mentioned technical problems, the utility model proposes a device for controlling the influence of foundation pit excavation by using the grouting ground wall at the bottom of the pit, which includes a ground wall arranged between the area to be constructed and the soil in the protection area. A plurality of inclinometer tubes are arranged in the ground connection wall, and the plurality of inclinometer tubes are evenly distributed along the length of the ground connection wall at intervals of 3 to 5 m. The number of grouting tubes is the same as the number of inclinometer tubes, and the positions of multiple grouting tubes in the length direction of the ground connection wall are the same as the positions of multiple inclinometer tubes. correspond.

Further speaking, the utility model adopts a device for controlling the impact of foundation pit excavation by grouting the ground connection wall at the bottom of the pit, wherein the length of the grouting pipe is consistent with the height of the ground connection wall, and the diameter of the grouting pipe is 100- 300mm, the grouting pipe is made of PVC pipe.

The length of the inclinometer pipe is consistent with the height of the ground connection wall.

Compared with the prior art, the beneficial effects of the utility model are:

(1) The utility model can realize fine control: by controlling the amount of grouting at the prefabricated grouting point and observing the value change of the inclinometer tube in time, the fine control of the deformation of the soil in the protected area can be realized.

(2) The utility model can realize multiple grouting: due to the reservation of multiple prefabricated grouting points at different depths, accurate, timely and flexible pressure compensation can be realized during the excavation process to control the enclosure structure soil deformation.

Description of drawings

Fig. 1 is the construction schematic diagram of ground connection wall in the utility model;

Figure 2 is a schematic diagram of the grouting facade after excavation of the foundation pit;

Fig. 3 is a schematic diagram of the grouting plane after excavation of the foundation pit shown in Fig. 2;

Fig. 4 is a schematic diagram of grouting after the excavation of the foundation pit of the next stage.

In the figure: 1-area to be constructed, 2-soil in the protected area, 3-ground connection wall, 4-inclinometer pipe, 5-horizontal support, 6-grouting pipe.

Detailed ways

The technical scheme of the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the described specific embodiments are only for explaining the utility model, and are not intended to limit the utility model.

As shown in Figures 2 and 3, the utility model proposes a device for controlling the influence of excavation of foundation pits by using the grouting ground wall at the bottom of the pit. The connection wall 3, the ground connection wall 3 is provided with a plurality of inclinometer tubes 4, and the plurality of inclinometer tubes 4 are evenly distributed along the length of the ground connection wall 3 at intervals of 3 to 5 m, as shown in Figure 3, the The length of the inclinometer pipe 4 is consistent with the height of the ground connection wall 3 . The upper part of the ground connecting wall 3 on one side of the desired construction area 1 is provided with multiple horizontal supports 5 and a plurality of grouting pipes 6, and the number of the grouting pipes 6 is the same as the number of the inclinometer pipes 4, as As shown in FIG. 3 , the positions of the plurality of grouting pipes 6 in the length direction of the ground connection wall 3 are in one-to-one correspondence with the positions of the plurality of inclinometer pipes 4 . As shown in Figure 2, the length of the grouting pipe 6 is consistent with the height of the ground wall 3, the diameter of the grouting pipe 6 is 100-300mm, and the grouting pipe 6 is made of PVC pipe.

The method for grouting by using the device proposed by the utility model to control the influence of foundation pit excavation by using the bottom grouting wall to control the excavation of the foundation pit includes the following steps:

Step 1. After the measurement and setting out, excavate the trench according to the results of the measurement and setting out;

Measurement and stakeout includes positioning and calibration control points and guide wall measurement. Ground wire points are set at places on the construction site that are conducive to protection and stakeout. According to the record of plane transfer piles, the total station is used to introduce the control points into the site, and the ground wire points are staked out. plane coordinates. Calculate the corner point coordinates of the center line of the ground connection wall according to the coordinates provided by the design drawings, use the ground wire control points, use the theodolite to stake out the corner points of the ground connection wall on the spot, and immediately prepare the protective piles.

Excavate trenches according to lofting results, pour plain concrete base form cushion, tie steel bars, set up formwork, and finally pour guide wall concrete. During the excavation process of the ground connection wall, the mud retaining wall is used to ensure the stability of the groove wall and prevent collapse.

The excavation trench includes: the excavation trench section is dug into a unit construction trench section by mechanical means "jump hole excavation method". Excavation of excavated earthwork. Take the soil while digging and loading it out. The quality inspection of the groove section reasonably arranges the sequence and number of grasping operations in each groove section to ensure the verticality of the two directions of the groove wall and the good installation of the device, and meets the requirement of 3‰ of groove forming accuracy.

Remove the soil silt deposited on the bottom of the tank, and replace the mud with excessive viscosity, specific gravity or sand content in the tank, so that the mud in the whole tank meets the quality requirements of the mud after bottom cleaning. Reasonably select the hanging brush according to the site conditions to ensure that the brush surface is in close contact with the joint surface to achieve the cleaning effect.

Step 2: Make a reinforcement cage according to the design requirements, install a plurality of inclinometer tubes 4 on the reinforcement cage according to the design requirements, and use aluminum blind rivets with a diameter of 4mm to connect the joints and the pipe body. Select the appropriate joint water seal type to prevent the grout from leaking into the pipe and blocking the inclinometer pipe during concrete pouring. The connected inclinometer pipe is pre-installed in the steel cage. In addition to ensuring the requirements of the inclinometer, the installation position should be able to safely avoid the bottom opening of the concrete delivery pipe and avoid the direct impact of the vibrator to protect the inclinometer pipe; if necessary, additional protective measures such as rib protection The ring should be protected by a steel cylinder within 2m of the bottom of the pipe and the lead-out structure or the ground, but the protection measures should not have adverse effects on other aspects. The inclinometer tube with the fixed installation position must be firmly fixed on the steel cage. Generally, the thicker main reinforcement is selected as the fixed attachment object and bound with soft iron wire; the distance between two adjacent binding points should not exceed 1m. When fixing, one group of the cross guide grooves of the inclinometer pipe should be in the ±A direction of the inclinometer after the steel cage is in place.

When the reinforcement cage is hoisted in place, care should be taken to keep the inclinometer tube 4 attached to it basically straight and avoid excessive bending; and clear water must be poured into the inclinometer tube 4 to overcome buoyancy and prevent wall mud from infiltrating, or to prevent pouring When the cement grout penetrates. After the reinforcement cage is in place, the mouth of the inclinometer tube 4 should be temporarily closed to prevent foreign matter from entering.

Step 3: Pour the concrete into the wall, and select the appropriate concrete ratio according to the design requirements. Start pouring concrete within 4 hours of the reinforcement cage being placed in the groove. When the concrete pouring is completed and has not yet solidified, open the mouth of the inclinometer tube 4 to constantly check whether the inclinometer tube 4 is full of clear water, and inject water if necessary to ensure that the clear water in the inclinometer tube 4 is full before the concrete solidifies. And it can be properly pressurized with heavy objects at the mouth of the nozzle to help overcome the buoyancy. Stop grouting when the designed grouting volume is reached. After the concrete is solidified, the hole must be washed with water of appropriate pressure to flush out the sediment at the bottom of the inclinometer tube, so that the upper and lower parts of the inclinometer tube are replaced by clean water to keep the whole tube unblocked. After the concrete is solidified, a ground connection wall 3 with a row of inclinometer tubes 4 is formed, as shown in FIG. 1 . All the pipes of the inclinometer pipe 4 are replaced with clear water;

Step 4: Install a row of grouting pipes 6 corresponding to the positions of the multiple inclinometer pipes along the length direction of the ground connection wall 3, as shown in Fig. 2 and Fig. 3 .

Step 5: Excavation of the foundation pit. When excavating the foundation pit, grout is injected into the grouting pipe 6, and the deformation of the soil in the protected area is controlled by observing the value change of the inclinometer pipe 4 to meet the requirements of soil deformation. As the excavation depth of the foundation pit deepens, a horizontal support 5 is added on the upper part of the ground connection wall 3 on one side of the foundation pit, as shown in FIGS. 2 and 4 . At the same time, remove the grouting pipe 6 above the excavation surface, and continue grouting below the excavation surface according to engineering needs to ensure soil deformation requirements; repeat the above operations until the excavation of the foundation pit is completed.

After the grouting is completed, insert the water pipe to the bottom of the grouting pipe, and clean the residual grout in the pipe for repeated grouting.

The traditional servo control of supporting axial force can only control the deformation of the enclosure structure above the excavation surface, but lacks effective control over the deformation of the enclosure structure below the excavation surface. Grouting and grouting while excavating, so that the ground connection wall can be used to provide passive side balance pressure with grouting under the condition of small deformation, so as to realize the stress control of the passive area in the foundation pit, so as to protect the bottom of the pit during each excavation The deformation of the structure is effectively controlled, and the operation is convenient and the cost is low.

Although the utility model has been described above in conjunction with the accompanying drawings, the utility model is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the enlightenment of the utility model, many deformations can be made without departing from the purpose of the utility model, and these all belong to the protection of the utility model.

Claims (3)

1. it is a kind of using hole rising pouring slurry ground-connecting-wall control influence of foundation excavation device, including setting be intended to construction area (1) in Ground-connecting-wall (3) between the protection zone soil body (2), which is characterized in that multiple inclinometer pipes (4) are equipped in the ground-connecting-wall (3), it is multiple Inclinometer pipe (4) is uniformly distributed for 3~5m according to spacing along the length of ground-connecting-wall (3), and being located at for the ground-connecting-wall (3) is intended to construction area (1) top of side is equipped with multiple tracks horizontally-supported (5) and multiple Grouting Pipes (6), number and the inclinometer pipe (4) of Grouting Pipe (6) Number it is identical, the position one of position and multiple inclinometer pipes (4) of multiple Grouting Pipes (6) on the length direction of ground-connecting-wall (3) One corresponds to.

2. according to claim 1 using the device of hole rising pouring slurry ground-connecting-wall control influence of foundation excavation, which is characterized in that institute State the length of Grouting Pipe (6) and highly consistent, a diameter of 100~300mm of the Grouting Pipe (6) of ground-connecting-wall (3), the note Slurry pipe (6) selects pvc pipe.

3. according to claim 1 using the device of hole rising pouring slurry ground-connecting-wall control influence of foundation excavation, which is characterized in that institute State the highly consistent of the length of inclinometer pipe (4) and ground-connecting-wall (3).