CN111424640A

CN111424640A - Vacuum preloading device and vacuum preloading method

Info

Publication number: CN111424640A
Application number: CN202010229152.4A
Authority: CN
Inventors: 李平; 孙益多; 陶俊; 陈育民; 高磊; 王震南
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2020-07-17

Abstract

The invention discloses a vacuum preloading device, which belongs to the technical field of soft soil foundation treatment and comprises a horizontal drainage pipe, at least one connecting hose and a drainage plate; two ends of the connecting hose penetrate through the horizontal drainage pipe and are respectively connected with the drainage plate in a sealing way; the connecting position of the connecting hose and the horizontal drainage pipe is connected in a sealing way; a vacuum transfer hole is arranged on the connecting hose positioned in the horizontal drainage pipe; the horizontal drainage pipe is connected with the switching pipe. The invention also discloses a vacuum preloading method, which comprises the following steps: arranging the drainage plate wrapped with the waterproof geotextile into the soft soil; after the horizontal drainage pipe is arranged, the connecting hose is hermetically connected with the horizontal drainage pipe; the connecting hose is hermetically connected with the drainage plate by using waterproof geotextile; and vacuumizing the horizontal drainage pipeline. The invention reduces the steps of laying a sand cushion layer and the like, can simply, conveniently and quickly realize the vacuum preloading of the soft soil foundation and improves the working efficiency.

Description

Vacuum preloading device and vacuum preloading method

Technical Field

The invention belongs to the technical field of soft soil foundation treatment, and particularly relates to a vacuum preloading device and a vacuum preloading method.

Background

A vacuum preloading method for reinforcing soft soil features that a horizontal draining sand cushion and vertical draining bodies are laid in soft foundation, an airtight film sealer is laid on the sand cushion, and a pipeline buried in sand cushion is used to pump out the pore water in the pores of soil body by vacuumizing unit to decrease the pressure of pore water and increase effective stress.

The method of achieving vacuum under existing conditions is to lay a horizontal draining sand mat and lay an airtight film enclosure over the sand mat. Not only a large amount of sandy soil resources are consumed, but also the environment pollution is caused by laying the film in a large area, and with the increasing shortage of sandy soil, the environmental problem is aggravated continuously, and the new vacuum preloading method is increasingly important.

Before the present invention, a Chinese patent (application No. 201610379590.2) discloses a vacuum preloading seepage consolidation method, which needs to coffer and dike around the region to be consolidated, and has long time consumption and low efficiency. Pumping underground water during vacuum preloading and recharging the underground water to the surface of the area to be reinforced, and covering the surface of the area to be reinforced with water to a certain height, so as to realize water covering preloading, water covering sealing and water covering seepage, but the treatment of the vertical drainage channel after the construction is finished is not considered.

Disclosure of Invention

The invention provides a vacuum preloading device which can carry out vacuum preloading on a soft soil foundation conveniently and quickly so as to improve the working efficiency.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: comprises a horizontal drain pipe, a drain board and a connecting hose; the connecting hose penetrates through the horizontal drainage pipe, two ends of the connecting hose are connected with the drainage plate, and the connecting hose is hermetically connected with the drainage plate; the connecting hose is hermetically connected with the horizontal drain pipe; the connecting hose inside the horizontal drainage pipe is provided with vacuum transferring hole.

Preferably, the aperture of the vacuum transfer hole is 5-10 mm.

Preferably, the connecting hoses are flexible pipes, the diameter of each pipe is 1-2cm, and the distance between every two connecting hoses is 60-120 cm.

Preferably, the horizontal drainage pipe is positioned in the middle of the drainage plates at two ends of the same connecting hose, and the horizontal drainage pipe is a PVC pipe.

Preferably, the connecting hose is hermetically connected with the drainage plate through waterproof geotextile, and the connecting hose is hermetically connected with the horizontal drainage pipe through a sealing connector.

The device has simple structure, is convenient to install during field operation, saves manpower and improves efficiency. According to the invention, the upper end of the drainage plate is wrapped by the waterproof geotextile and is connected with one end of the connecting hose in a sealing manner, so that the wrapping range of the upper soil body and the deep drainage type drainage plate waterproof geotextile forms a closed whole, a sand cushion layer or cofferdam embankment in the traditional vacuum preloading foundation treatment scheme is replaced, the cost is greatly reduced, and the method is more economic and environment-friendly.

The invention also provides a vacuum preloading method, which reduces the steps of laying a sand cushion layer or cofferdam diking and the like, can simply, conveniently and quickly realize vacuum preloading of a soft soil foundation and improves the working efficiency.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a vacuum preloading method is realized by adopting the vacuum preloading device, and comprises the following steps: arranging a drainage plate into the soft soil, and exposing one end connected with the hose out of the ground surface according to a preset height; after the horizontal drainage pipe is arranged, the connecting hose is hermetically connected with the horizontal drainage pipe; the connecting hose is connected with the drainage plate in a sealing way by using a sealing connecting piece; and vacuumizing the horizontal drainage pipeline.

Furthermore, the connection hose and the drain board are hermetically connected, namely, the hose and the drain board are hermetically connected by waterproof geotextile, and clay slurry is filled into a waterproof geotextile wrapping section on the connection hose.

Further, the range of the waterproof geotextile wrapped by the drainage plate is 2-4 m; the preset height is 30-50 cm.

Further, after the vacuumizing is finished, the drainage plate is sealed.

Further, the sealing of the drain board comprises the following steps: and adopting cement paste or bentonite slurry to fill the drainage plate.

The method overcomes the defect that a sand cushion layer or a cofferdam is laid on a large scale in the traditional vacuum preloading method, and improves the working efficiency. The method considers the problem of sealing of the pore passage of the underground drainage plate after the construction, and injects cement slurry or bentonite slurry into the drainage plate to plug the pore inside the drainage plate, thereby playing a role in eliminating the drainage passage after the construction and enabling the foundation after the construction to be more stable.

Drawings

Fig. 1 is a schematic structural diagram of a vacuum preloading device according to an embodiment of the present invention;

FIG. 2 is a partial schematic view of an embodiment of the present invention;

fig. 3 is a cross-sectional view of an embodiment of the present invention.

Wherein: 1-horizontal drain pipe, 2-connecting hose, 21-sealing connector, 22-vacuum transfer hole, 3-drain board, 4-waterproof geotextile, 5-adapter tube and 6-vacuum pump.

Detailed Description

For a better understanding of the nature of the invention, its description is further set forth below in connection with the specific embodiments and the drawings.

As shown in fig. 1 to 3, a vacuum preloading device includes a horizontal drain pipe 1, a connection hose 2, and a drain board 3. Two ends of the connecting hose 2 penetrate through the horizontal drainage pipe 1 and are respectively connected with the drainage plate 3. The joint of the connecting hose 2 and the horizontal drainage pipe 1 is sealed, and the joint of the connecting hose 2 and the horizontal drainage pipe 1 is sealed by a sealing connector 21. The connecting hose 2 positioned in the horizontal drainage pipe 1 is provided with a vacuum transfer hole 22, and the aperture of the vacuum transfer hole is 5-10 mm. The drain board 3 adopts waterproof geotextile 4 and connecting hose 2 to carry out sealing connection. The wrapping range of the waterproof geotextile 4 on the drainage plate 3 is preferably 2-4 m. The horizontal drainage pipe 1 is connected with a vacuum pump 6 through an adapter pipe 5.

The horizontal drainage pipe 1 is a PVC pipe, and the distance between the two connecting hoses 2 is 60-120 cm. The connecting hose 2 is a flexible pipe with the diameter of about 1-2 cm. The drainage plate 3 consists of a drainage core belt and an outer wrapping filter membrane.

A vacuum preloading method is realized by adopting the vacuum preloading device, and specifically comprises the following steps:

step 1: and (3) arranging the drain board 3 wrapped with the waterproof geotextile 4 into the soft soil, and exposing the ground surface at the end wrapped with the waterproof geotextile 4 according to a preset height. The range of the drain board 3 wrapping the waterproof geotextile is 2-4 m. And a certain length is reserved after the waterproof geotextile 4 wraps the drainage plate 3 for subsequent connection with the connecting hose 2. The preset height of the drainage plate 3 exposed out of the ground surface is 30-50 cm, so that the drainage plate is conveniently connected with the connecting hose 2. Utilize the trigger of beating to beat to establish drain bar 3, it is sealed to pour into clay mud in the downthehole of the soil body of beating into of drain bar 3, makes upper soil body and the waterproof geotechnological cloth parcel scope of drain bar constitute an inclosed whole, has replaced the combination of airtight film and sand bed course in the traditional vacuum preloading ground treatment scheme, not only has reduced the cost by a wide margin, also more economic environmental protection.

Step 2: after the horizontal drainage pipe 1 is arranged, the connecting hose 2 is hermetically connected with the horizontal drainage pipe 1. The horizontal drainage pipe 1 is arranged between the two rows of drainage plates 3. Both ends of the connection hose 2 are inserted through the horizontal drainage pipe 1, and the connection hose 2 and the horizontal drainage pipe 1 are hermetically fixed by a sealing connector 21 so that the vacuum transfer hole 22 is positioned inside the horizontal drainage pipe 1.

And step 3: the connecting hose 2 is hermetically connected with the drain board 3 by using waterproof geotextile 4. Wrapping with waterproof geotextile 4 to connect the two ends of the connecting hose 2 with the top of the drain board 3, and pouring clay slurry into the wrapping section of the waterproof geotextile 4 on the connecting hose 2 to enhance the sealing effect.

And 4, step 4: and vacuumizing the horizontal drainage pipeline. One end of the horizontal drainage pipe 1 is blocked, and the other end is connected with a vacuum pump 6 through an adapter 5. And starting the vacuum pump 6 to vacuumize. The vacuum pressure is transmitted from the horizontal drainage pipe 1 to the connecting hose 2, then to the drainage plate 3, and diffused into the foundation, so that water and gas in the foundation seep out along with the drainage plate 3, are collected into the horizontal drainage pipe 1 through the vacuum transmitting holes 22, and are discharged at the free end of the horizontal drainage pipe 1 after being collected by a certain amount. And performing various field monitoring, drawing a sedimentation-time relation curve, and continuing reinforcing for a period of time by adopting vacuum preloading until sedimentation is stable and meets the unloading condition.

And 5: and after the vacuumizing is finished, sealing the drainage plate. After the evacuation, sealed after discharging the steam in the horizontal drain pipe 1, change vacuum pump 6 into pumping installations, toward horizontal drain pipe 1 pump sending cement paste or bentonite mud, in the hole of transmitting drain bar 3 through coupling hose 2, sealed drain passage in the drain bar 3.

Step 6: and (3) unfastening the waterproof geotextile 4 wrapping the connecting hose 2 to separate the connecting hose 2 from the drain board 3, and horizontally draining the water pipe 1 and the connecting hose 2 by using clean water and flushing water and recovering.

It should be noted that while the invention has been described in terms of the above-mentioned embodiments, there are many other embodiments of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended that all such changes and modifications be covered by the appended claims and their equivalents. .

Claims

1. The utility model provides a vacuum preloading device which characterized in that: comprises a horizontal drain pipe, a drain board and a connecting hose; the connecting hose penetrates through the horizontal drainage pipe, two ends of the connecting hose are connected with the drainage plate, and the connecting hose is hermetically connected with the drainage plate; the connecting hose is hermetically connected with the horizontal drain pipe; the connecting hose inside the horizontal drainage pipe is provided with vacuum transferring hole.

2. The vacuum preloading device as recited in claim 1, wherein: the aperture of the vacuum transfer hole is 5-10 mm.

3. The vacuum preloading device as recited in claim 1, wherein: the connecting hoses are flexible pipes, the diameter of each pipe is 1-2cm, and the distance between every two connecting hoses is 60-120 cm.

4. The vacuum preloading device as recited in claim 1, wherein: the horizontal drain pipe is arranged in the middle of the drain plates at two ends of the same connecting hose and is a PVC pipe.

5. The vacuum preloading device as recited in claim 1, wherein: the connecting hose is connected with the drain board in a sealing way through waterproof geotextile, and the connecting hose is connected with the horizontal drain pipe in a sealing way through a sealing connector.

6. A vacuum preloading method is realized by the vacuum preloading device of any one of claims 1 to 5, and is characterized by comprising the following steps:

arranging a drainage plate into the soft soil, and exposing one end connected with the hose out of the ground surface according to a preset height;

after the horizontal drainage pipe is arranged, the connecting hose is hermetically connected with the horizontal drainage pipe;

connecting the connecting hose with a drain board in a sealing way;

and vacuumizing the horizontal drainage pipeline.

7. The vacuum preloading method as recited in claim 5, wherein: the connecting hose and the drain board are connected in a sealing mode, the hose and the drain board are connected in a sealing mode through waterproof geotextile, and clay slurry is poured into a waterproof geotextile wrapping section on the connecting hose.

8. The vacuum preloading method as recited in claim 5, wherein: the range of wrapping the waterproof geotextile by the drainage plate is 2-4 m; the preset height is 30-50 cm.

9. The vacuum preloading method as recited in claim 5, wherein: and after the vacuumizing is finished, sealing the drainage plate.

10. The vacuum preloading method as recited in claim 9, wherein: the step of sealing the drain board comprises the following steps: and (3) pouring cement slurry or bentonite slurry into the drainage plate to seal the pores in the drainage plate.