CN114892690A - Construction method of double-wall steel-jacketed box cofferdam - Google Patents
Construction method of double-wall steel-jacketed box cofferdam Download PDFInfo
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- CN114892690A CN114892690A CN202210572196.6A CN202210572196A CN114892690A CN 114892690 A CN114892690 A CN 114892690A CN 202210572196 A CN202210572196 A CN 202210572196A CN 114892690 A CN114892690 A CN 114892690A
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- 238000010276 construction Methods 0.000 title claims abstract description 65
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 142
- 239000010959 steel Substances 0.000 claims abstract description 142
- 238000000034 method Methods 0.000 claims abstract description 53
- 239000004576 sand Substances 0.000 claims abstract description 32
- 230000008569 process Effects 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000002689 soil Substances 0.000 claims abstract description 21
- 238000005553 drilling Methods 0.000 claims abstract description 20
- 238000005086 pumping Methods 0.000 claims abstract description 17
- 238000007789 sealing Methods 0.000 claims abstract description 7
- 230000001681 protective effect Effects 0.000 claims description 20
- 238000009412 basement excavation Methods 0.000 claims description 13
- 239000004927 clay Substances 0.000 claims description 12
- 229910003460 diamond Inorganic materials 0.000 claims description 3
- 239000010432 diamond Substances 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
- 230000002441 reversible effect Effects 0.000 claims description 3
- 239000010802 sludge Substances 0.000 claims 1
- 239000002002 slurry Substances 0.000 claims 1
- 230000007246 mechanism Effects 0.000 description 4
- 238000004873 anchoring Methods 0.000 description 3
- 230000000670 limiting effect Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011900 installation process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D19/00—Keeping dry foundation sites or other areas in the ground
- E02D19/02—Restraining of open water
- E02D19/04—Restraining of open water by coffer-dams, e.g. made of sheet piles
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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Abstract
The invention belongs to the technical field of cofferdams for hydraulic engineering, and provides a construction method of a double-wall steel boxed cofferdam, which comprises the following steps: step S1, after the pile foundation construction is finished, the drilling platform is dismantled; step S2, a hole guiding platform is set up, a rotary excavating machine is adopted to carry out hole guiding construction around the hole guiding platform so as to form a ring groove matched with the bottom of the cofferdam on the riverbed, the hole guiding depth is not higher than the designed bottom elevation position of the cofferdam, sand is backfilled after hole guiding is finished, and the sand is backfilled to the riverbed elevation so as to replace the rock-soil layer at the designed lowering position of the cofferdam with sand; step S3, sequentially splicing and lowering the double-wall steel sleeve box cofferdam in sections; step S4, carrying out water pumping and excavating operation, and installing a multilayer inner support in the cofferdam; and step S5, pouring the bottom sealing concrete. According to the invention, before the cofferdam is lowered, the operation of hole guiding, slotting and soil taking is carried out in advance, and the rock-soil layer at the designed lowering position of the cofferdam is replaced by sand; in the process of lowering the subsequent cofferdam, the lowering resistance is small, so that the cofferdam can be quickly and smoothly lowered in place.
Description
Technical Field
The invention belongs to the technical field of cofferdams for hydraulic engineering, and particularly relates to a construction method of a double-wall steel boxed cofferdam.
Background
At present, when the cofferdam is constructed, the cofferdam is usually lowered by adopting a mud suction sinking process. However, when the clay layer in the rock-soil layer where the main pier is located is thick, mud suction and excavation are difficult; at the moment, the cofferdam is placed downwards by adopting a mud suction sinking process, so that the cofferdam placing efficiency is low. In addition, construction organization and quality control difficulties are often caused by limited construction periods. Therefore, the conventional cofferdam lowering construction method is not suitable for cofferdam construction when the clay layer in the rock-soil layer at the position of the main pier is thick.
For example, the 3# main pier of the main bridge of the Huaihuan Huaihe river is positioned in the south water area of the Huaihe river of the Huaihe Guangxi county of the Huaihe Guangxi town, and the rock-soil layer mainly comprises silt filled soil, cohesive soil, pebbles and gneiss. The average thickness of the covering soil layer is about 8.37 m; the average thickness of the completely weathered gneiss strip is about 15.49 m; the average thickness of the broken block type strongly weathered gneiss strip is about 19.07 m; the average thickness of the mesomorphic gneiss zone is about 19.87 m. The pile end of the earth prospecting design is suitable for being deeply embedded, the full and strong weathering bottom interface fluctuates along with the fluctuation of the terrain, the soil layer and the strong weathering bedrock are broken, the bearing capacity is low, the pile end is not suitable for serving as a foundation bearing layer, and the medium weathering bedrock core is complete and has high bearing capacity. The construction of the 3# main pier double-wall steel pouring jacket cofferdam has the following construction difficulties: 1. deep soil penetration: the average elevation of the 3# main pier cofferdam riverbed is about +3m, the elevation of the cofferdam bottom is-10.8 m, the elevation of the bearing platform bottom is-6 m, the elevation of the sealed bottom is-10 m, and the riverbed is required to be dug out by 13 m. The highest design water level of the cofferdam is +18.5m, and the water head difference is 28.5 m. 2. Difficulty in excavation: the 3# main pier cofferdam needs to penetrate through mucky soil, silty clay, clay and pebble layers in the process of lowering the cofferdam and finally enters the completely weathered gneiss layer, and the clay layer is thick.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a construction method of a double-wall steel boxed cofferdam, which can solve the defects in the prior art.
In order to achieve the above purpose, the invention provides the following technical scheme:
a construction method of a double-wall steel box cofferdam comprises the following steps:
step S1, after the pile foundation construction is completed, the drilling platform is dismantled;
step S2, a hole guiding platform is set up, a rotary excavating machine is adopted to carry out hole guiding construction around the hole guiding platform, so that a ring groove matched with the bottom of the cofferdam is formed on the riverbed, the hole guiding depth is not higher than the designed bottom elevation position of the cofferdam, sand is backfilled after hole guiding is finished, and the sand is backfilled to the riverbed elevation so as to replace the rock-soil layer at the designed lowering position of the cofferdam with sand;
step S3, sequentially splicing and lowering the double-wall steel sleeve box cofferdam in sections;
step S4, carrying out water pumping and excavating operation, and installing a multilayer inner support in the cofferdam;
and step S5, pouring the bottom sealing concrete.
In the method for constructing a double-wall steel boxed cofferdam as described above, preferably, in step S2, the ring groove is formed by connecting a plurality of holes, adjacent holes are engaged with each other, and the engagement width is not less than the wall thickness of the cofferdam.
In the above-described double-wall steel box cofferdam construction method, preferably, in step S2, the hole-by-hole construction is performed sequentially, and the specific construction steps of a single hole are as follows:
step S201, firstly, drilling a guide hole protection cylinder;
step S202, digging and drilling in the guide hole protecting cylinder;
step S203, a crescent protective cylinder is placed in the guide hole protective cylinder;
step S204, back filling sand into the crescent-shaped casing;
step S205, pulling out the guide hole protective sleeve; reserving the crescent-shaped pile casing to take the concave side of the crescent-shaped pile casing as the guide for installing the guide hole pile casing during construction of the corresponding next adjacent hole site;
in the whole hole guiding construction process of the step S2, each bearing platform jointly and circularly uses two crescent-shaped protective sleeves and one hole guiding protective sleeve;
and after the construction of the leading hole of the next adjacent hole site is finished, pulling out the crescent protective cylinder corresponding to the previous hole site.
In the method for constructing a double-wall steel box cofferdam as described above, preferably, before step S201, a horizontally disposed guide frame is first installed to guide the guide hole casing so as to prevent the guide hole casing from deviating.
In the method for constructing a double-wall steel boxed cofferdam as described above, preferably, in step S202, different drill footage speeds are selected according to geological conditions during the excavation and drilling process.
In the above method for constructing a double-wall steel boxed cofferdam, preferably, step S3 specifically includes the following steps:
step S301, detaching the hole guiding platform, and installing an assembling platform on the steel casing;
step S302, assembling a first section of double-wall steel cofferdam on the assembling platform, then installing a hoisting system at the top of the steel casing, and installing a guide system at the periphery of the steel casing, wherein the guide system is in guide fit with the inner wall of the first section of double-wall steel cofferdam; hoisting the first section of double-wall steel cofferdam through the hoisting system, dismantling the part of the splicing platform which hinders the lowering, and then lowering the first section of double-wall cofferdam through the hoisting system;
and step S303, assembling and lowering each subsequent double-wall steel cofferdam.
In the above-described double-wall steel box cofferdam construction method, preferably, in step S303: in the lowering process of each section of double-wall steel cofferdam, the hoisting system is adopted to integrally lower the double-wall steel cofferdam, and the lowering is assisted by a method of carrying out sand suction operation at the bottom of a riverbed and increasing the self weight of the cofferdam.
In the above construction method of the double-wall steel-sheathed box cofferdam, preferably, in step S4, the concrete method of the water pumping excavation operation is as follows: firstly, temporarily fixing the top of the double-wall steel boxed cofferdam with the steel casing, then completely pumping water in the double-wall steel boxed cofferdam by adopting a water pump, and then carrying out mud suction and excavation;
in the mud suction excavation process, according to the difference of the geological conditions of the pier position, different modes are planned to be adopted: dredging, namely excavating by adopting a gas lift reverse circulation mud suction method, and pumping the mud to a mud ship; excavating a powdery clay layer by adopting an excavator, simultaneously, manually loosening clay, and then transporting the excavated soil outwards by adopting a grab excavator;
and in the process of pumping water and excavating, lowering the inner supports of all layers.
In the construction method of the double-wall steel box cofferdam, the installation sequence of the inner supports of the multiple layers preferably follows the principle of top to bottom.
In the construction method of the double-wall steel boxed cofferdam, preferably, the cross section of the double-wall steel boxed cofferdam is square;
each layer of the inner supports are of a diamond structure which is internally connected to the middle part of each side wall of the double-wall steel pouring jacket cofferdam.
Has the advantages that: to the thick ground layer of clay layer, the cofferdam is transferred in-process: according to the invention, before the cofferdam is lowered, the operation of hole guiding, slotting and soil taking is carried out in advance, and the rock-soil layer at the designed lowering position of the cofferdam is replaced by sand; in the process of lowering the subsequent cofferdam, the lowering resistance is small, so that the cofferdam can be quickly and smoothly lowered in place. Compared with the method for lowering the cofferdam through the mud suction sinking process, the method has the advantages that the speed for lowering the cofferdam is greatly increased, the construction difficulty is reduced, and the construction period is shortened.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a schematic view showing an installation position of a guide frame according to the present invention;
FIG. 2 is a schematic view of the guide frame and the guide hole casing according to the present invention;
FIG. 3 is a schematic view of sand backfilling into a pilot hole casing according to the present invention;
FIG. 4 is a drawing of a hole routing arrangement according to the present invention;
FIG. 5 is a schematic diagram of the combination of a crescent-shaped casing and a guide hole casing in the present invention;
FIG. 6 is a schematic view of the hole guiding construction according to the present invention;
FIG. 7 is a schematic view of the lowering of the first section of double-wall steel cofferdam of the present invention;
FIG. 8 is a floor plan of the hoist system of the present invention;
FIG. 9 is a schematic view of the construction of the inner support of the present invention;
fig. 10 is a schematic structural view of the double-wall steel pouring jacket cofferdam of the present invention.
The names corresponding to the reference numbers in the figures are: 1-first section double-wall steel cofferdam; 2-a second section of double-wall steel cofferdam; 3-a third section of double-wall steel cofferdam; 4-single-wall steel cofferdam; 5-steel casing; 51-angle pile steel casing; 52-edge steel casing; 6-a guiding system; 7-hoisting and placing the system; 71-lifting point; 72-lower lifting point; 73-lowering the beam; 74-a boom; 75-anchoring corbels; 8-inner support; 9-a wall bin plate; 10-a wall bin; 11-side panel A; 12-side panel B; 13-splicing the platform; 14-a lead hole platform; 15-a guide frame; 16-a landing stage; 17-trestle bridge pipe pile; 18-guiding hole protecting cylinder; 19-crescent protective cylinder; 191-limit steel plate card.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
As shown in fig. 1-10, a construction method of a double-wall steel boxed cofferdam comprises the following steps:
and step S1, after the pile foundation construction is finished, the drilling platform is dismantled.
And step S2, setting up the hole guiding platform 14, performing hole guiding construction around the hole guiding platform 14 by using a rotary excavating machine to form a ring groove matched with the bottom of the cofferdam on the riverbed, wherein the hole guiding depth is not higher than the designed bottom elevation position of the cofferdam, backfilling sand after hole guiding is completed, and backfilling the sand to the riverbed elevation so as to replace the rock-soil layer at the designed lowering position of the cofferdam with the sand.
Step S3, sequentially splicing and lowering the double-wall steel sleeve box cofferdam in sections; specifically, the double-wall steel-sleeve box cofferdam can be lowered by two sections, three sections, four sections, five sections or six sections.
And step S4, performing water pumping and excavating operation, and installing a plurality of layers of inner supports 8 in the cofferdam.
And step S5, pouring the bottom sealing concrete.
In an alternative embodiment of the present invention, in step S2, the ring groove is formed by connecting a plurality of holes, and adjacent holes are engaged with each other, and the engaging width is not less than the wall thickness of the cofferdam. Specifically, the plurality of holes are communicated with each other to form the ring groove.
In an alternative embodiment of the present invention, in step S2, during the hole-by-hole construction, the specific construction steps of a single hole are as follows:
step S201, firstly, drilling a guide hole protecting cylinder 18 to prevent hole collapse;
step S202, digging and drilling operation is carried out in the guide hole protecting cylinder 18;
step S203, the crescent protection cylinder 19 is placed in the guide hole protection cylinder 18 to reach the designed elevation, and the limiting steel plate clips 191 are arranged on two sides of the top of the crescent protection cylinder 19 to prevent the crescent protection cylinder 19 from rotating and ensure the position accuracy of the crescent protection cylinder 19;
step S204, back filling sand into the crescent protective cylinder 19; specifically, the dump truck transports sand to an operation platform, an excavator is matched with a string barrel to backfill the sand into a hole through a buried guide hole protection barrel 18, and the sand sinks under the action of self-weight through the self-compactness of the sand and is backfilled to the elevation of an original river bed;
step S205, the guiding hole casing 18 is pulled out, and the crescent casing 19 is retained, so that the concave side of the crescent casing 19 is used as a guide for installing the guiding hole casing 18 during the construction of the next adjacent hole.
Preferably, in the whole hole guiding construction process of step S2, each bearing platform is provided with two crescent-shaped casings 18 and one circular hole guiding casing 18, and is recycled. After the hole leading construction of the next adjacent hole site is completed, the crescent-shaped pile casing 18 corresponding to the previous hole site is pulled out.
In the step S2, each bearing platform is provided with two crescent-shaped pile casings 18 and one circular guide hole pile casing 18, and the circular guide hole pile casings are recycled, and the concrete construction method of the guide hole construction includes:
(1) carrying out lead hole construction of the 1 st hole site: inserting and punching a guide hole protecting cylinder 18 at a preset 1 st hole position; then, digging and drilling operation is carried out in the guide hole protection cylinder; then, a first crescent protective barrel 19 is placed in the guide hole protective barrel; then, back filling sand into the first crescent protection cylinder; then the leading hole protecting cylinder is pulled out, the first crescent protecting cylinder 19 is reserved, and the concave side of the crescent protecting cylinder corresponding to the 1 st hole site is used as the guide of the leading hole protecting cylinder for installing the 2 nd hole site;
(2) and (3) carrying out lead hole construction of a 2 nd hole: inserting and drilling a lead hole protecting cylinder at the 2 nd hole site, and then performing hole digging operation; a crescent protective barrel is placed in the leading hole protective barrel corresponding to the 2 nd hole site; then, sand is back filled into the crescent protective cylinder corresponding to the 2 nd hole site; then pulling out a leading hole protection cylinder corresponding to the 2 nd hole site and a crescent protection cylinder corresponding to the 1 st hole site;
(3) and then repeating the steps, and sequentially performing the construction of each subsequent hole site until the hole leading construction of all the hole sites is completed.
In other embodiments, a plurality of guide hole protection cylinders can be adopted in the guide hole construction process; and after all the hole positions are subjected to hole leading, taking out each crescent protective cylinder 19.
In an alternative embodiment of the present invention, before step S201, a horizontally disposed guiding frame 15 is first installed to guide the guiding hole casing 18, so as to prevent the guiding hole casing 18 from deviating and ensure the casing verticality. The guide frame 15 is accurately positioned, and the verticality and the depth of the lead hole slotting are ensured. The guide frame 15 is located between the trestle platform 16 and the lead hole platform 14.
Specifically, the guide frame 15 is fixedly arranged between the steel casing 5 and the trestle tubular pile 17; the installation process comprises the steps of firstly correspondingly welding a bracket between the steel casing 5 and the trestle tubular pile 17, and then fixedly installing the guide frame 15 on the bracket.
In an optional embodiment of the present invention, in step S202, different drill bit footage speeds are selected according to geological conditions during the drilling process, specifically:
when the soft stratum is changed into the hard stratum, the speed is reduced and the slow advance is carried out;
in the stratum with easy diameter shrinkage, the hole sweeping times are properly increased to prevent the diameter shrinkage;
in the hard plastic layer, drilling at a high rotating speed is adopted to improve the drilling efficiency;
for a sand layer, slow drilling is carried out at a slow rotating speed;
if a pebble layer appears in the actual construction process, the following measures are taken: and (3) for the pebble layer with smaller particle size, adopting a bucket type drill bit to drill at a low speed, and for the pebble layer with larger particle size, adopting a conical spiral drill bit to drill, then replacing the bucket type drill bit to remove slag, and repeating the steps until the pebble layer passes through. The drilling slag is transported out of the construction site in time and is abandoned to a proper place to meet the requirement of environmental protection.
In an optional embodiment of the invention, a wall-bin plate 9 is arranged in each section of the double-wall steel cofferdam, and the double-wall steel cofferdam is divided into a plurality of wall bins 10 by arranging the wall-bin plate 9.
In an optional embodiment of the present invention, step S3 specifically includes the following steps:
step S301, the hole guiding platform 14 is removed, and the assembling platform 13 is installed on the steel casing 5.
Step S302, assembling the first double-wall steel cofferdam 1 on an assembling platform 13, then installing a hoisting system 7 at the top of a steel casing 5, installing a guide system 6 at the periphery of the steel casing 5, and guiding and matching the guide system 6 with the inner wall of the first double-wall steel cofferdam 1; the first double-wall steel cofferdam 1 is hoisted through the hoisting system 7, the part of the assembly platform 13 which is blocked to be lowered is removed, and then the first double-wall cofferdam is lowered through the hoisting system 7.
The guiding system 6 comprises a horizontal mechanism, one end of the horizontal mechanism is fixedly connected with the periphery of the steel casing 5, and the other end of the horizontal mechanism is rotatably assembled with a roller to roll along the inner wall of the double-wall steel-sheathed box cofferdam. The horizontal mechanism is double-spliced I-shaped steel, the double-spliced I-shaped steel is welded together by adopting steel plates (the thickness is 1cm), and one end of the double-spliced I-shaped steel is provided with a rolling shaft for a roller.
The central line of the guide system 6 is radially consistent with the steel casing 5, and a clearance of 15mm-25mm (for example, 15mm, 18mm, 20mm, 22mm or 25mm) is reserved between the guide system 6 and the inner wall of the double-wall steel boxed cofferdam to form a rolling friction system.
And step S303, assembling and lowering each subsequent double-wall steel cofferdam.
In an optional embodiment of the present invention, step S303 specifically includes: assembling each subsequent section of double-wall steel cofferdam at the top of the corresponding previous section of double-wall steel cofferdam;
in the lowering process of each section of double-wall steel cofferdam, the double-wall steel cofferdam is wholly lowered by adopting a hoisting system 7, and the lowering is assisted by a method of carrying out sand suction operation at the bottom of a riverbed and increasing the self weight of the cofferdam. The method for adding the self weight of the cofferdam can be pouring concrete or water into the wall bin. Preferably, the method for adding the dead weight of the cofferdam can be to pour the concrete of the wall bin into the wall bin, wherein the concrete of the wall bin is C30 concrete.
In an optional embodiment of the invention, after the last section of double-wall steel cofferdam is completely lowered, the single-wall steel cofferdam 4 is assembled on the top of the last section of double-wall steel cofferdam. This single-walled steel cofferdam 4 has the effect of preventing unrestrained, prevents the water level variation that leads to because of the weather reason, has promoted the safety in utilization nature of cofferdam.
In an alternative embodiment of the present invention, in step S4, the concrete method of the water pumping excavation operation is: firstly, temporarily fixing the top of the double-wall steel boxed cofferdam with a steel casing 5, then completely pumping water in the double-wall steel boxed cofferdam by adopting a water pump, and then carrying out mud suction and excavation;
in the process of mud suction and excavation, different modes are planned to be adopted according to the different geological conditions of the pier position: dredging, namely excavating by adopting a gas lift reverse circulation mud suction method, and pumping the mud to a mud ship; excavating a powdery clay layer by adopting an excavator, simultaneously, manually loosening clay, and then transporting the excavated soil outwards by adopting a grab excavator;
in the process of pumping water and excavating, lowering each layer of inner supports 8; the mounting sequence of the multilayer inner supports 8 follows the principle of top to bottom; the method specifically comprises the following steps: and when water is pumped to 1m below the designed elevation of the support 8 in the corresponding layer, the inner support 8 of the corresponding layer is installed.
In an alternative embodiment of the invention, the cross section of the double-wall steel boxed cofferdam is square (for example, square or rectangular); correspondingly, each support 8 in each layer is of a diamond structure which is internally connected with the middle part of each side wall of the double-wall steel pouring jacket cofferdam. When the cross section of the double-wall steel boxed cofferdam is square, the support 8 in each layer is of a square structure. Specifically, the inner support 8 is installed at the position of a wall bulkhead 9 of the double-wall steel cofferdam so as to avoid the inner support 8 from damaging the side wall by water pressure.
Example 1:
a construction method of a double-wall steel box cofferdam comprises the following steps:
step S1, after the pile foundation construction is completed, the drilling platform is dismantled;
step S2, setting up a pilot hole platform 14, conducting pilot hole construction, and replacing the rock-soil layer at the cofferdam design lowering position with sand;
step S3, the double-wall steel sleeve box cofferdam is divided into three sections for assembly and lowering, and the method specifically comprises the following steps:
step S301, the hole guiding platform 14 is removed, and the assembling platform 13 is installed on the steel casing 5.
The number of the steel protecting cylinders 5 is 9, the 9 steel protecting cylinders 5 are divided into three rows, and each row is uniformly distributed with 3 steel protecting cylinders 5 which are in square distribution. The steel casing 5 comprises 4 corner pile steel casings 51, 4 middle steel casings 52 and 1 central steel casing, wherein the corner pile steel casings 51 are positioned at four corners, the middle steel casings 52 are positioned in the center of each side of the square, and the central steel casing is positioned in the center of the square.
After the assembly platform 13 is installed, the four corner pile steel casing 51 are lengthened.
Step S302, assembling the first double-wall steel cofferdam 1 on an assembling platform 13, then installing a hoisting system 7 at the top of a steel casing 5, installing a guide system 6 at the periphery of the steel casing 5, and guiding and matching the guide system 6 with the inner wall of the first double-wall steel cofferdam 1; the first double-wall steel cofferdam 1 is hoisted through the hoisting system 7, the part of the assembly platform 13 which is blocked to be lowered is removed, and then the first double-wall cofferdam is lowered through the hoisting system 7.
The hoisting system 7 comprises two vertical cross lowering beams 73 fixedly arranged at the tops of the four corner pile steel casing 51, a hoisting point is arranged at the end part of each lowering beam 73 and is an upper hoisting point 71, a vertically arranged jack and a vertically arranged suspender 74 are arranged at each upper hoisting point 71, and 8 jacks and 8 suspenders are arranged in total (the suspender adopts a prestressed steel strand). The lower lifting points 72 are arranged on the inner side of the inner wall of the first double-wall steel cofferdam 1, and the positions of the lower lifting points correspond to the upper lifting points one by one. Specifically, an anchoring bracket 75 is welded on the inner wall of the first double-wall steel cofferdam 1, and a hanging hole for inserting the hanging rod 74 is formed in the anchoring bracket 75, and the position is a lower hanging point.
2 guide systems 6 are welded on the outer side of each corner pile steel casing 51, and 1 guide system 6 is connected on the outer side of each steel casing 52 in 4 sides, and the total number is 12.
In the lowering process, when the first section of double-wall cofferdam reaches self-floating after entering water, pouring concrete in the wall bin of the first section of double-wall cofferdam; when the top of the first section of double-wall cofferdam is level with the splicing platform 13, stopping the lowering; after the first double-wall cofferdam is put down in place, the first double-wall cofferdam is continuously hung by the hanging system 7; and when the wall bin concrete reaches the design strength, separating the first section of double-wall cofferdam from the hoisting system 7.
The precise positioning measures of the first double-wall steel cofferdam 1 are as follows:
in the lowering process, scales are marked on the steel strand, and the verticality of the first section of double-wall cofferdam is adjusted every time the steel strand is lowered by about 15cm, so that the lowering process of the first section of double-wall cofferdam is stable;
and (3) accurately positioning after the first section of double-wall cofferdam is put in place: the vertical position of the first section of double-wall cofferdam is accurately adjusted by controlling the water level in the wall bin of the first section of double-wall cofferdam; and the plane position of the first section of double-wall cofferdam is accurately adjusted through the guide system 6.
Step S303, assembling a second double-wall steel cofferdam section 2 at the top of the first double-wall steel cofferdam section 1; after assembly is completed, the two sections of double-wall steel cofferdams are integrally lowered by adopting a hoisting system 7; in the lowering process, when the first double-wall steel cofferdam 1 is inserted into sand and sinks to a certain depth and then stops sinking, sand suction operation is carried out at the bottom of the riverbed, the hoisting system 7 is synchronously released, and the lowering is continued; when the top of the second section of double-wall steel cofferdam 2 is level with the splicing platform 13, stopping the lowering;
assembling a third section of double-wall steel cofferdam 3 at the top of the second section of double-wall steel cofferdam 2 to complete the integral assembling of the double-wall steel boxed cofferdam; then, integrally lowering the double-wall steel sleeve box cofferdam by adopting a hoisting system 7; in the lowering process, sand suction operation is carried out at the bottom of the riverbed, the hoisting system 7 is synchronously released, and the double-wall steel sleeve box cofferdam is continuously lowered under the action of the balance weight; when the top of the double-wall steel box cofferdam is level with the splicing platform 13, the lowering is stopped.
In addition, each double-wall steel cofferdam is a square structure consisting of 8 side plates A11 and 4 side plates B12, wherein the corner is the side plate B. The assembling process of each section of double-wall steel cofferdam is as follows: two corners at the opposite corners of the square are used as two assembling starting points and are assembled in two ways, and the two ways are assembled in a clockwise or anticlockwise assembling sequence.
When the first section of double-wall cofferdam is put down, the height of the concrete in the wall bin poured into the cofferdam is 2.06 m; when the second double-wall cofferdam is put down, the height of the silo-wall concrete poured into the cofferdam is 2.45 m; when the third section of cofferdam is lowered, the height of the wall bin concrete poured into the cofferdam is 2.55 m. Therefore, the total height of the poured silo-wall concrete from the bottom of the cofferdam is 8.79 m.
And step S304, assembling the single-wall steel cofferdam 4 at the top of the double-wall steel boxed cofferdam.
Step S4, carrying out water pumping and excavating operation, and installing a plurality of layers of inner supports 8 in the cofferdam;
and step S5, pouring bottom sealing concrete, wherein the bottom sealing concrete is constructed by adopting a vertical conduit multipoint underwater pouring method. The bottom sealing concrete pouring is carried out in a mode of gradually advancing from two sides to the center.
It should be understood that the above description is only exemplary, and the embodiments of the present application do not limit the present invention.
The above description is only exemplary of the invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the invention is intended to be covered by the appended claims.
Claims (10)
1. The construction method of the double-wall steel box cofferdam is characterized by comprising the following steps:
step S1, after the pile foundation construction is completed, the drilling platform is dismantled;
step S2, a hole guiding platform is set up, a rotary excavating machine is adopted to carry out hole guiding construction around the hole guiding platform, so that a ring groove matched with the bottom of the cofferdam is formed on the riverbed, the hole guiding depth is not higher than the designed bottom elevation position of the cofferdam, sand is backfilled after hole guiding is finished, and the sand is backfilled to the riverbed elevation so as to replace the rock-soil layer at the designed lowering position of the cofferdam with sand;
step S3, sequentially splicing and lowering the double-wall steel sleeve box cofferdam in sections;
step S4, carrying out water pumping and excavating operation, and installing a multilayer inner support in the cofferdam;
and step S5, pouring the bottom sealing concrete.
2. The method for constructing a double-wall steel boxed cofferdam according to claim 1, wherein the ring groove is formed by connecting a plurality of holes, adjacent holes are mutually engaged, and the engaging width is not less than the wall thickness of the cofferdam in step S2.
3. The construction method of the double-wall steel boxed cofferdam according to claim 2, characterized in that in step S2, the hole-by-hole construction is performed in sequence during the hole-leading construction, and the specific construction steps of the single hole are as follows:
step S201, firstly, drilling a guide hole protection cylinder;
step S202, performing digging and drilling operation in the guide hole protecting cylinder;
step S203, a crescent protective cylinder is placed in the guide hole protective cylinder;
step S204, back filling sand into the crescent-shaped casing;
step S205, pulling out the guide hole protective sleeve; reserving the crescent-shaped pile casing to take the concave side of the crescent-shaped pile casing as the guide for installing the guide hole pile casing during construction of the corresponding next adjacent hole site;
in the whole hole guiding construction process of step S2, each bearing platform jointly and circularly uses two crescent-shaped protective cylinders and one hole guiding protective cylinder;
and after the construction of the leading hole of the next adjacent hole site is finished, pulling out the crescent protective cylinder corresponding to the previous hole site.
4. The method for constructing a double-wall steel casing cofferdam according to claim 3, wherein before step S201, a horizontally arranged guide frame is first installed for guiding the guide hole casing to prevent the guide hole casing from deviating.
5. The construction method of the double-wall steel boxed cofferdam according to claim 3, wherein in step S202, different drill bit footage speeds are selected according to geological conditions during the excavation and drilling process.
6. The construction method of the double-wall steel boxed cofferdam according to claim 1, wherein the step S3 specifically comprises the steps of:
step S301, detaching the hole guiding platform, and installing an assembling platform on the steel casing;
step S302, assembling a first section of double-wall steel cofferdam on the assembling platform, then installing a hoisting system at the top of the steel casing, and installing a guide system at the periphery of the steel casing, wherein the guide system is in guide fit with the inner wall of the first section of double-wall steel cofferdam; hoisting the first section of double-wall steel cofferdam through the hoisting system, dismantling the part of the splicing platform which hinders the lowering, and then lowering the first section of double-wall cofferdam through the hoisting system;
and step S303, assembling and lowering each subsequent double-wall steel cofferdam.
7. The construction method of the double-wall steel boxed cofferdam according to claim 5, characterized in that in step S303: in the lowering process of each section of double-wall steel cofferdam, the hoisting system is adopted to integrally lower the double-wall steel cofferdam, and the lowering is assisted by a method of carrying out sand suction operation at the bottom of a riverbed and increasing the self weight of the cofferdam.
8. The construction method of the double-wall steel-sheathed box cofferdam of claim 1, wherein in the step S4, the concrete method of the water pumping excavation operation is as follows: firstly, temporarily fixing the top of the double-wall steel boxed cofferdam with the steel casing, then completely pumping water in the double-wall steel boxed cofferdam by adopting a water pump, and then carrying out mud suction and excavation;
in the mud suction excavation process, according to the difference of the geological conditions of the pier position, different modes are planned to be adopted: dredging, namely excavating by adopting a gas lift reverse circulation mud suction method, and pumping the sludge to a slurry ship; excavating a powdery clay layer by adopting an excavator, simultaneously, manually loosening clay, and then transporting the excavated soil outwards by adopting a grab excavator;
and in the process of pumping water and excavating, lowering the inner supports of all layers.
9. The method for constructing a double-walled steel boxed cofferdam according to claim 8, wherein the installation sequence of the inner supports of the multiple layers follows the principle of top to bottom.
10. The construction method of the double-wall steel boxed cofferdam according to claim 9, characterized in that the cross section of the double-wall steel boxed cofferdam is square;
each layer of the inner supports are of a diamond structure which is internally connected to the middle part of each side wall of the double-wall steel pouring jacket cofferdam.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115233714A (en) * | 2022-08-31 | 2022-10-25 | 中交一公局集团有限公司 | Continuous hole leading and slotting construction method for deep-water bare rock geological cofferdam |
| CN115419089A (en) * | 2022-09-01 | 2022-12-02 | 中铁七局集团武汉工程有限公司 | Shallow water bedrock geological bearing platform foundation pit construction method |
| CN116180780A (en) * | 2023-04-13 | 2023-05-30 | 华侨大学 | Pile bottom gap blocking device and method for deep water hard rock bare rock bored concrete pile |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101368389A (en) * | 2008-09-24 | 2009-02-18 | 中铁大桥局集团第五工程有限公司 | Single and double-wall combined steel cofferdam construction method and its single and double-wall combined steel cofferdam |
| JP2009068196A (en) * | 2007-09-11 | 2009-04-02 | Toyo Constr Co Ltd | Construction method for cofferdam wall using steel segment |
| CN108457282A (en) * | 2017-04-24 | 2018-08-28 | 中交公局厦门工程有限公司 | Deep water hard rock is without back cover steel sheet pile cofferdam construction method |
| CN108457283A (en) * | 2017-04-24 | 2018-08-28 | 中交公局厦门工程有限公司 | Deep water hard rock steel sheet-pile cofferdam pilot hole fluting grouting construction method |
| CN111980020A (en) * | 2020-09-16 | 2020-11-24 | 中铁四局集团有限公司 | Construction method of double-wall steel suspension box cofferdam of main bridge bearing platform of super-large bridge |
| DE202021103023U1 (en) * | 2020-06-24 | 2021-07-30 | China Tiesiju Civil Engineering Group Co.Ltd. | A complete positioning and assembly structure for double-walled steel box dams and short groups of protective tubes |
| CN113502837A (en) * | 2021-07-10 | 2021-10-15 | 中铁一局集团(广州)建设工程有限公司 | Sandstone stratum cofferdam leading hole slag leakage prevention construction process |
| CN113550340A (en) * | 2021-07-23 | 2021-10-26 | 广州市市政工程机械施工有限公司 | Construction method of deepwater foundation of double-wall steel cofferdam without sealing bottom under deepwater rock entering condition |
| KR102382034B1 (en) * | 2021-08-18 | 2022-04-01 | 한선형 | Construction method of continuous cut off wall |
-
2022
- 2022-05-23 CN CN202210572196.6A patent/CN114892690B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009068196A (en) * | 2007-09-11 | 2009-04-02 | Toyo Constr Co Ltd | Construction method for cofferdam wall using steel segment |
| CN101368389A (en) * | 2008-09-24 | 2009-02-18 | 中铁大桥局集团第五工程有限公司 | Single and double-wall combined steel cofferdam construction method and its single and double-wall combined steel cofferdam |
| CN108457282A (en) * | 2017-04-24 | 2018-08-28 | 中交公局厦门工程有限公司 | Deep water hard rock is without back cover steel sheet pile cofferdam construction method |
| CN108457283A (en) * | 2017-04-24 | 2018-08-28 | 中交公局厦门工程有限公司 | Deep water hard rock steel sheet-pile cofferdam pilot hole fluting grouting construction method |
| DE202021103023U1 (en) * | 2020-06-24 | 2021-07-30 | China Tiesiju Civil Engineering Group Co.Ltd. | A complete positioning and assembly structure for double-walled steel box dams and short groups of protective tubes |
| CN111980020A (en) * | 2020-09-16 | 2020-11-24 | 中铁四局集团有限公司 | Construction method of double-wall steel suspension box cofferdam of main bridge bearing platform of super-large bridge |
| CN113502837A (en) * | 2021-07-10 | 2021-10-15 | 中铁一局集团(广州)建设工程有限公司 | Sandstone stratum cofferdam leading hole slag leakage prevention construction process |
| CN113550340A (en) * | 2021-07-23 | 2021-10-26 | 广州市市政工程机械施工有限公司 | Construction method of deepwater foundation of double-wall steel cofferdam without sealing bottom under deepwater rock entering condition |
| KR102382034B1 (en) * | 2021-08-18 | 2022-04-01 | 한선형 | Construction method of continuous cut off wall |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115233714A (en) * | 2022-08-31 | 2022-10-25 | 中交一公局集团有限公司 | Continuous hole leading and slotting construction method for deep-water bare rock geological cofferdam |
| CN115419089A (en) * | 2022-09-01 | 2022-12-02 | 中铁七局集团武汉工程有限公司 | Shallow water bedrock geological bearing platform foundation pit construction method |
| CN116180780A (en) * | 2023-04-13 | 2023-05-30 | 华侨大学 | Pile bottom gap blocking device and method for deep water hard rock bare rock bored concrete pile |
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| CN114892690B (en) | 2024-01-16 |
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