CN103243704B

CN103243704B - Shallow mud foundation treatment method

Info

Publication number: CN103243704B
Application number: CN201310159842.7A
Authority: CN
Inventors: 戴林伟; 姚炎明; 朱明栋; 陈磊; 许旺
Original assignee: Zhoushan Ocean Research Center of ZJU
Current assignee: Zhoushan Ocean Research Center of ZJU
Priority date: 2013-05-02
Filing date: 2013-05-02
Publication date: 2015-03-18
Anticipated expiration: 2033-05-02
Also published as: CN103243704A

Abstract

The invention discloses a shallow mud foundation treatment method. The method includes: zoning a site to be treated; laying drain boards in a soft soil layer from top to bottom by a floating raft; connecting the ends and middle of the drain boards to a tube drainage system through tube plate connectors; connecting the upper end of the tube drainage system to a vacuum unit; laying woven fabric, geogrid, nonwoven geotextile and seal film on a mud surface from top to bottom; performing vacuum preloading and unloading after requirements are met. The shallow mud foundation treatment method has the advantages that construction period is shortened greatly, vacuum transmission is effective, using sand cushions is avoided, and deformation of the drain boards is reduced greatly.

Description

A kind of shallow mud foundation treatment method

Technical field

The invention belongs to the technical field of the basement process such as construction work, port works, hydraulic engineering, be specifically related to a kind of shallow mud foundation treatment method.

Background technology

At present, in conjunction with the engineering of desilting and dredging of navigation channel and basin, dredging silt becomes the filler of reclaiming land around sea.Because blowing-filling sludge water content is high, compressibilty is large, and bearing capacity is extremely low, is even in flow regime, can not carry the weight of people and simple construction equipment, cannot carry out the construction of sand mat of subgrade, plastic draining board or sand wick.Traditional soft soil foundation process flow has: (1) natural drying; (2) on weak soil, woven cloth, chaste tree fragrant plant and geo-grid etc. are laid, then Cast-in-situ Piles in Sand-filling; (3) set band drain, lay diaphragm seal; (4) vacuum or piling prepressing.

Problems existing: (1) natural drying time is longer, short then 3-4 month, long then more than 1 year, have a strong impact on the progress of subsequent development construction activity; (2) backfill medium coarse sand as drainage blanket, need a large amount of extra large sand, many regional sea sand resources critical shortage, illegal mining sea sand situation is rampant, has a strong impact on sea wall, submerged pipeline and other extra large work facilities; (3) the design treatment degree of depth of blowing-filling sludge formation soft foundation reaches about 20m, and according to Land character requirement, majority will carry out secondary basement process, therefore, adopt the design of advanced treating must cause unnecessary waste in basement process; (4) new hydraulically filled sludge ground water content is large, compressibilty is high, and under load action, after discharging consolidation process, the compression ratio of Soft Soil Layer is up to 15% ~ 40%, causes band drain with soil deformation, even fractures, and greatly affects its drainage performance.

Summary of the invention

The object of the invention is to solve that existing vacuum preloading method exists is long in time limit, need to use the problems such as the distortion of extra large sand, band drain is large in a large number.

Central scope of the present invention: subregion is carried out in pending place; Utilize buoyant raft, in Soft Soil Layer, lay band drain from bottom to top; By tube sheet connector, band drain two ends and central region are connected with pipe drain system; Pipe drain system upper end is connected with vacuum equipment; Woven cloth, geo-grid, non-woven geotextile and sealing film is laid from bottom to top in mud face; Carry out vacuum preloading, unload after meeting the demands.

The inventive method is specifically:

Step 1. subregion: construct pontoon bridge in conjunction with light material with bamboo pole, steel pipe, carries out cut zone along pontoon bridge periphery color steel, lays plastic sheeting formation retaining and enclose curtain inside color steel.

Step 2. envelope wall or ditch construction.

Step 3. place retaining: retaining in cut zone.

Step 4. lays band drain: utilize buoyant raft, and band drain is laid in layering from bottom to top, needs to determine spacing of prefabricated drain and Soft Soil Layer treating depth according to design.

Step 5. pipe drain system is laid: deployment tube connector for substrate in the middle part of band drain two ends and band drain, tube sheet connector is connected with pipe drain system, band drain is inserted Soft Soil Layer down to respective depth together with tube sheet connector, and pipe drain system upper end is connected with vacuum equipment; Tube sheet connector two ends are flat and have scissor-shaped opening, and width can be customized according to plastic draining board specification, and aspect ratio band drain thickness is slightly high; In the middle of tube sheet connector, a cylindric port is arranged in front, in cylindric port, arrange that filtration sponge prevents mud from entering and causes pipe drain system jams, cylindric port is connected with pipe drain system by threeway, and cylindric port latus rectum can be determined according to tee junction latus rectum; In cylindric port both sides near scissor-shaped opening make position, each layout one rubber membrane, when rubber membrane being pulled out after band drain Inserting Tube connector for substrate, tightly entangles band drain; Respectively there is a rubber case at tube sheet connector two ends, allow scissor-shaped opening tightly close up, be drawn in gutter to prevent the silt when construction in later period; This system can make the through whole tube sheet connector of band drain.

Step 6. lays geotextiles: after treating that band drain and pipe drain system are laid, utilize buoyancy of water to lay woven cloth, geo-grid and geotextiles thereon.

Step 7. lays diaphragm seal: under film, arrange probe measurement vacuum, utilizes buoyancy of water to lay diaphragm seal on geotextiles.

Step 8. vacuum preloading, unloads after meeting the demands.

Beneficial effect of the present invention: the present invention's effective reduction of erection time, vacuum transmission effect be good, do not need to use sand cushion, greatly to reduce band drain distortion; Band drain of the present invention is laid convenient, and be convenient to mechanized construction, portion of material is recyclable to be recycled; Tube sheet connector of the present invention solves laying level when carrying out vacuum preloading process to band drain, because vacuum decay causes the problem of middle part vacuum degree deficiency, is applicable to large-area shallow layer foundation process.

Accompanying drawing explanation

Fig. 1 is the sectional drawing of this method treatment of soft foundation.

Fig. 2 is the top view of this method treatment of soft foundation.

Fig. 3 a and Fig. 3 b is the schematic diagram of tube sheet connector.

In figure: 1 diaphragm seal, 2 geotextiles, 3 geo-grid, 4 woven cloth, 5 Soft Soil Layers, 6 flexible pipes, 7 vacuum equipments, 8 pontoon bridges, 9 sealing ditches, 10PVC manages, 11 envelope walls, 12 tube sheet connectors, 13 cylindric ports, 14 filter sponge, 15 rubber membranes, 16 band drains, 17 rubber cases.

Detailed description of the invention

Below in conjunction with example, the invention will be further described

As depicted in figs. 1 and 2, the present invention, specific implementation method step is as follows:

Step (1) sets up pontoon bridge: construct pontoon bridge 8 with bamboo pole, steel pipe in conjunction with light material, and pontoon bridge as pioneer road, can place vacuum equipment simultaneously.

Step (2) subregion: carry out subregion along pontoon bridge periphery color steel, lays plastic sheeting formation retaining and encloses curtain inside color steel.

Step (3) envelope wall 11 (sealing ditch 9) construction.

Step (4) place retaining: with water pump to water filling in cut zone, the depth of water can make the floating movement of buoyant raft be advisable for during construction.

Step (5) lays band drain: utilize buoyant raft, lay plastic draining board 16 from bottom to top, lay one deck band drain 16 on Soft Soil Layer 5 top layer, band drain 16 two ends remain on mud face, Soft Soil Layer 5 treating depth is generally no more than 3m, band drain 16 Lay interval 0.8 to 1.5m.

Step (6) is current, and band drain 16 1 volume that market is sold is about 200m, and deployment tube connector for substrate 12 in the middle part of band drain 16, is connected tube sheet connector 12 with pipe drain system; Band drain 16 is inserted Soft Soil Layer 5 to respective depth together with tube sheet connector 12, see Fig. 3 a and Fig. 3 b.

Band drain 16 two ends are connected with pipe drain system by tube sheet connector 12 by step (7); Band drain 16 is inserted Soft Soil Layer 5 to respective depth together with tube sheet connector 12.

Pipe drain system upper end is connected with vacuum equipment 7 by step (8).

Step (9) lays geotextiles: after treating that band drain 16 and pipe drain system are laid, utilize buoyancy of water to lay woven cloth 4, geo-grid 3 and geotextiles 2 thereon.

Step (10) lays diaphragm seal: under film, arrange probe measurement vacuum, utilize buoyancy of water to lay diaphragm seal 1 on geotextiles 2.

Step (11) vacuum preloading, unloads after meeting the demands.

In above-mentioned steps (6), pipe drain system tubing can adopt the pvc pipe 10 meeting requirement of strength; Pipe drain system top and vacuum equipment 7 connecting place need flexible pipe 6, and reserved certain length.

Above-mentioned steps (6) and (7) middle tube sheet connector 12 total length 20cm; Tube sheet connector 12 two ends are flat and have scissor-shaped opening, and tube sheet connector 12 width can be customized according to band drain 16 specification; The long 7cm of scissor-shaped opening, aspect ratio band drain 16 thickness is slightly high; A cylindric port one 3 is arranged in the middle front of tube sheet connector 12, in cylindric port one 3, arrange that filtration sponge 14 prevents mud from entering and causes pipe drain system jams, cylindric port one 3 is connected with pipe drain system by threeway, and cylindric port one 3 latus rectum can be determined according to tee junction latus rectum; In cylindric port one 3 both sides near scissor-shaped opening make position, each layout one length 12cm rubber membrane 15, when rubber membrane 15 being pulled out after band drain 16 Inserting Tube connector for substrate 12, tightly entangles band drain 16; Respectively there is a rubber case 17 at tube sheet connector 12 two ends, allow scissor-shaped opening tightly close up, be drawn in gutter to prevent the silt when construction in later period; The feature of this device is to make the through whole tube sheet connector 12 of band drain 16.

Claims

1. a shallow mud foundation treatment method, is characterized in that the method comprises the following steps:

Step 1. subregion: construct pontoon bridge in conjunction with light material with bamboo pole, steel pipe, carries out cut zone along pontoon bridge periphery color steel, lays plastic sheeting formation retaining and enclose curtain inside color steel;

Step 2. envelope wall or the construction of sealing ditch;

Step 3. place retaining: retaining in cut zone;

Step 4. lays band drain: utilize buoyant raft, and band drain is laid in layering from bottom to top, needs to determine spacing of prefabricated drain and Soft Soil Layer treating depth according to design;

Step 5. pipe drain system is laid: deployment tube connector for substrate in the middle part of band drain two ends and band drain, tube sheet connector is connected with pipe drain system, band drain is inserted Soft Soil Layer down to respective depth together with tube sheet connector, and pipe drain system upper end is connected with vacuum equipment; Tube sheet connector two ends are flat and have scissor-shaped opening, and width can be customized according to plastic draining board specification, and aspect ratio band drain thickness is slightly high; In the middle of tube sheet connector, a cylindric port is arranged in front, in cylindric port, arrange that filtration sponge prevents mud from entering and causes pipe drain system jams, cylindric port is connected with pipe drain system by threeway, and cylindric port latus rectum can be determined according to tee junction latus rectum; In cylindric port both sides near scissor-shaped opening make position, each layout one rubber membrane, when rubber membrane being pulled out after band drain Inserting Tube connector for substrate, tightly entangles band drain; Respectively there is a rubber case at tube sheet connector two ends, allow scissor-shaped opening tightly close up, be drawn in gutter to prevent the silt when construction in later period; This system can make the through whole tube sheet connector of band drain;

Step 6. lays geotextiles: after treating that band drain and pipe drain system are laid, utilize buoyancy of water to lay woven cloth, geo-grid and geotextiles thereon;

Step 7. lays diaphragm seal: under film, arrange probe measurement vacuum, utilizes buoyancy of water to lay diaphragm seal on geotextiles;

Step 8. vacuum preloading, unloads after meeting the demands.