CN109024670B

CN109024670B - Underground comprehensive pipe gallery protection and reinforcement system penetrating through buried high-voltage cable and reinforcement method

Info

Publication number: CN109024670B
Application number: CN201810662402.6A
Authority: CN
Inventors: 林彪峰; 曾宏强
Original assignee: China Construction Eighth Engineering Division Co Ltd
Current assignee: China Construction Eighth Engineering Division Co Ltd
Priority date: 2018-06-25
Filing date: 2018-06-25
Publication date: 2021-04-06
Anticipated expiration: 2038-06-25
Also published as: CN109024670A

Abstract

The invention discloses a protection and reinforcement system and a reinforcement method for a buried high-voltage cable through an underground comprehensive pipe gallery, wherein the system comprises bearing buttresses which are arranged at two ends of a penetrated section of the buried high-voltage cable, and each bearing buttress comprises filling piles arranged at two sides of the buried high-voltage cable and a cover beam connected to the tops of the filling piles at the two sides; the bearing beam is connected to the tops of the cover beams of the bearing buttresses at two ends; the suspension reinforcing structure comprises pocket bottom beams which stretch across two sides of the bottom of the buried high-voltage cable, and two ends of the pocket bottom beams are connected below the bearing beams in a suspension mode through suspension wires; the foundation pit supporting structure comprises obliquely inserted combined steel sheet piles which are arranged at two ends of a penetrated section of a buried high-voltage cable and located on the inner side of a bearing buttress, wherein the obliquely inserted combined steel sheet piles comprise first obliquely inserted steel sheet piles and second obliquely inserted steel sheet piles, and the first obliquely inserted steel sheet piles and the second obliquely inserted steel sheet piles are gradually obliquely drawn together from top to bottom. Ensure that the excavation in-process concrete is full of buries ground high tension cable structure safety, and do not influence utility tunnel construction.

Description

Underground comprehensive pipe gallery protection and reinforcement system penetrating through buried high-voltage cable and reinforcement method

Technical Field

The invention relates to the field of motors, in particular to a protection and reinforcement system and a reinforcement method for a buried high-voltage cable penetrating through an underground comprehensive pipe gallery.

Background

The urban underground comprehensive pipe gallery is an intensive and scientific urban infrastructure, effectively solves the problems of spider web and the like caused by the maintenance and expansion of various pipelines in the urban development process, effectively improves the urban image, and plays an important role in creating a harmonious urban ecological environment. However, in the construction process of the urban underground comprehensive pipe gallery engineering, the links are more, and the surrounding underground environment is relatively complex.

The urban underground comprehensive pipe gallery may encounter a 110KV buried high-voltage cable supplied with power by a high-speed rail in the construction process, and the interruption of the high-speed rail power supply network causes great hidden dangers to the operation order and safety of the high-speed rail, so that great urgency and necessity are provided for the research, development and application of the 110KV buried high-voltage cable protection and reinforcement technology in the construction process of the comprehensive pipe gallery.

Disclosure of Invention

Aiming at the defects existing in the prior art or potential defects, the invention provides a protection and reinforcement system and a reinforcement method for a buried high-voltage cable to pass through an underground comprehensive pipe gallery, which are convenient to apply and safe and stable in protection and reinforcement.

In order to achieve the above object, a first aspect of the present invention provides a protection and reinforcement system for a buried high voltage cable passing through an underground utility tunnel, comprising:

the bearing buttresses are arranged at two ends of a penetrated section of the buried high-voltage cable, and each bearing buttress at the two ends comprises a cast-in-place pile arranged at two sides of the buried high-voltage cable and a cover beam connected to the tops of the cast-in-place piles at the two sides;

the bearing beam is connected to the tops of the cover beams of the bearing buttresses at two ends;

the hanging and reinforcing structure comprises pocket bottom beams which stretch across two sides of the bottom of the buried high-voltage cable, and two ends of each pocket bottom beam are connected below the bearing beams in a hanging mode through slings;

the foundation pit supporting structure comprises two ends of a penetrated section of the buried high-voltage cable and obliquely inserted combined steel sheet piles located on the inner side of the bearing buttress, wherein the obliquely inserted combined steel sheet piles comprise first obliquely inserted steel sheet piles and second obliquely inserted steel sheet piles, and the first obliquely inserted steel sheet piles and the second obliquely inserted steel sheet piles are gradually inclined from top to bottom and are close to each other.

In an embodiment of the reinforcement system, each of the load-bearing buttresses comprises two cast-in-place piles arranged along an axial direction of the underground utility tunnel to be constructed.

In an embodiment of the reinforcement system, the obliquely-inserted combined steel sheet piles are arranged along an axial direction of an underground comprehensive pipe gallery to be constructed.

In an embodiment of the reinforcement system, gaps, which are not closed, between the first obliquely inserted steel sheet pile and the second obliquely inserted steel sheet pile below the buried high-voltage cable are sealed by mud blocking plates.

In an embodiment of the reinforcement system, the mud blocking plates are welded to opposite inner sides of the first obliquely inserted steel sheet pile and the second obliquely inserted steel sheet pile at two ends.

In an embodiment of the reinforcement system, the buried high voltage cable is inserted into a cable duct bank, and the cable duct bank is fixed on the bottom beam.

The invention provides a protection and reinforcement method for a buried high-voltage cable through an underground comprehensive pipe gallery, which comprises the following steps:

arranging bearing buttresses at two ends of a penetrated section of a buried high-voltage cable, constructing filling piles at two sides of the buried high-voltage cable, and constructing a cover beam at the tops of the filling piles of which the construction at the two ends is finished;

hoisting bearing beams on the tops of the cover beams of the bearing buttresses at two ends;

excavating a working pit at the penetrated section of the buried high-voltage cable to the lower part of the buried high-voltage cable;

the method comprises the steps that the working pit is utilized to install a suspension reinforcing structure, two ends of a pocket bottom beam are suspended and connected below a bearing beam through a sling, and the pocket bottom beam stretches across two sides of the bottom of the buried high-voltage cable;

and arranging a foundation pit supporting structure at two ends of a penetrated section of the buried high-voltage cable, wherein inclined-insertion combined steel sheet piles are arranged at two sides of the buried high-voltage cable at the two ends, each inclined-insertion combined steel sheet pile comprises a first inclined-insertion steel sheet pile and a second inclined-insertion steel sheet pile and is positioned at the inner side of the bearing buttress, and the first inclined-insertion steel sheet piles and the second inclined-insertion steel sheet piles are gradually inclined from top to bottom.

In an embodiment of the reinforcement system, when constructing the cast-in-place pile, the constructed cast-in-place pile is raised a distance above a designed elevation of a pile top, and before constructing the cap beam, the cast-in-place pile of the distance is chiseled, and the cap beam is constructed on the top of the cast-in-place pile with the chiseled pile top.

In an embodiment of the reinforcement system, after the construction of the obliquely inserted composite steel sheet pile is completed, the method further includes the steps of: and a gap which is not closed between the first inclined steel inserting sheet pile and the second inclined steel inserting sheet pile below the buried high-voltage cable is sealed by a mud blocking plate.

In an embodiment of the reinforcement system, the buried high-voltage cable is inserted into a cable duct bank, and the cable duct bank is fixed on the bottom beam when the bottom beam is connected in a hanging manner.

Due to the adoption of the technical scheme, the invention has the following beneficial effects: and temporarily reinforcing the 110KV buried high-voltage cable by adopting a steel structure stool type portal suspension method, and restoring the original state after the underground comprehensive pipe gallery is constructed. The basic principle of the steel structure 'stool type' portal suspension method is that the process of protecting and reinforcing the concrete full-wrapped 110KV buried high-voltage cable is carried out through the suspension method of the pile foundation, the cover beam, the bearing steel beam, the sling and the pocket bottom beam, the safety of the concrete full-wrapped 110KV buried high-voltage cable structure in the excavation process is guaranteed, and the construction of an underground comprehensive pipe gallery is not influenced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a layout relation diagram of an underground comprehensive pipe gallery and a buried high-voltage cable in the embodiment of the invention.

Fig. 2 is a floor plan of a buried high voltage cable in a reinforcement architecture according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a load-bearing buttress in a reinforcing system according to an embodiment of the present invention.

Fig. 4 is a reinforcement diagram of the cover beam of fig. 3.

Fig. 5 is a schematic structural view of a load-bearing beam in the reinforcing system according to the embodiment of the present invention.

Fig. 6 is a sectional view taken along line a-a of fig. 5.

Fig. 7 is a schematic structural diagram of a suspension reinforcement structure in a reinforcement system according to an embodiment of the present invention.

Fig. 8 is a plan layout view of a foundation pit supporting structure in the reinforcing system according to the embodiment of the invention.

Fig. 9 is a sectional view taken along line B-B of fig. 8.

FIG. 10 is a main process flow diagram of a reinforcement method according to an embodiment of the present invention.

Fig. 11 is a flow chart of a construction process of the cast-in-place punched pile in the embodiment of the invention.

Fig. 12 is a flow chart of a capping beam construction process in the embodiment of the invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

The invention is further described with reference to the following figures and specific embodiments.

Referring to fig. 1, the embodiment is that an urban underground comprehensive pipe gallery 10 and a group of 110KV buried high-voltage cables 11 are built and buried underground synchronously, the buried high-voltage cables 11 are buried underground for about 1m, a concrete full-package power pipe arrangement process is adopted for protection, and the underground comprehensive pipe gallery 10 penetrates through the buried high-voltage cables 11. This buried high voltage cable 11 intersects the underground utility tunnel 10 of the present engineering design.

Because the 110KV buried high-voltage cable 11 is a special line for urban power supply, the special line for high-speed rail can be shut down according to conventional relocation, great hidden dangers are caused to the operation order and safety of high-speed rail, and the relocation process is complicated, difficult and long in time consumption. How to solve the problem that the special 110KV buried high-speed rail power supply line is not changed and disconnected, ensure that the concrete outer packing structure of the 110KV buried high-voltage cable is safe and the high-speed rail normally runs without being hatched, and simultaneously ensure that the construction of the urban underground comprehensive pipe gallery is not influenced by the buried high-voltage cable is a difficult point.

Through the scheme comparison and analysis, the temporary reinforcement is carried out on the power grid by adopting the steel structure 'stool type' door frame suspension method, and the method mainly comprises the following steps: the device comprises four parts, namely a bearing buttress, a bearing beam, a suspension reinforcing structure and a foundation pit supporting structure, wherein the bearing buttress is arranged at two ends of a penetrated section of a buried high-voltage cable, and the bearing buttresses at the two ends respectively comprise filling piles arranged at two sides of the buried high-voltage cable and cover beams connected to the tops of the filling piles at the two sides; the bearing beam is connected to the tops of the cover beams of the bearing buttresses at two ends; the hanging and reinforcing structure comprises pocket bottom beams which stretch across two sides of the bottom of the buried high-voltage cable, and two ends of each pocket bottom beam are hung and connected below the bearing beams through slings; the foundation pit supporting structure comprises obliquely inserted combined steel sheet piles which are arranged at two ends of a penetrated section of the buried high-voltage cable and located on the inner side of the bearing buttress, wherein the obliquely inserted combined steel sheet piles comprise first obliquely inserted steel sheet piles and second obliquely inserted steel sheet piles, and the first obliquely inserted steel sheet piles and the second obliquely inserted steel sheet piles are gradually obliquely drawn together from top to bottom.

By adopting the scheme, the following problems are mainly solved:

(1) the concrete outer-wrapping structure of the 110KV buried high-voltage cable is guaranteed to be safe and the high-speed rail can not be influenced under the condition that a 110KV buried high-speed rail power supply line is not changed and is not powered off, and meanwhile, the construction of the urban underground comprehensive pipe gallery is guaranteed not to be influenced by the buried high-voltage cable.

(2) The problem that the conventional 110KV high-voltage cable is changed to cause the shutdown of a special high-speed rail line is solved, and the defects of complicated changing procedures, high difficulty, long time consumption and the like are overcome.

(3) Compared with a concrete 'stool type' portal suspension method, the steel structure 'stool type' portal suspension method is more economical, shortens the construction period and is green and environment-friendly.

The concrete reinforcing method comprises the following steps:

1. as shown in fig. 2, the urban underground comprehensive pipe gallery penetrated through the 110KV buried high-voltage cable of the embodiment is reinforced. The reinforcement measures adopt a steel structure 'stool type' portal suspension method to temporarily reinforce the power line pipes 111, the power line pipes are wrapped outside the multiple buried high-voltage cables, the underground comprehensive pipe gallery returns to the original state after the construction is finished, and the plane position of the 110KV buried high-voltage cable is shown in figure 2.

2. As shown in fig. 3 and 4, the load-bearing buttresses 12 are provided at both ends of the traversed section of the buried high-voltage cable 11, and the load-bearing buttresses 12 at both ends (i.e., each load-bearing buttress 12) each include a cast-in-place pile 121 provided at both sides of the buried high-voltage cable 11 and a capping beam 122 connected to the tops of the cast-in-place piles 121 at both sides.

Further, each of the load-bearing buttresses 12 includes two cast-in-place piles 121, and the two cast-in-place piles 121 are arranged along the axial direction of the utility tunnel 10 to be constructed and spaced apart from the utility tunnel 10 by a certain distance.

Specifically, a phi 800mm cast-in-place pile 121 and a 800mmx1000mm rectangular reinforced concrete cover beam 122 are adopted to form a door-shaped bearing buttress 12, and the cast-in-place pile 121 enters the bedrock by 1 meter in an end-supported pile and impact type hole forming mode.

3. As shown in fig. 5 and 6, the load-bearing beam 13 is used as a stressed main beam and is connected to the top of the cover beam 122 of the load-bearing buttress 12 at two ends. Wherein, the spandrel girder 13 adopts 4mmx worker 63C type I-steel 131, adopts 10 mm's stiffening steel plate 132 to link to each other between the I-steel 131.

4. As shown in fig. 7, the hanging reinforcement structure includes a bottom pocket beam 141 crossing both sides of the bottom of the buried high voltage cable 11, and both ends of the bottom pocket beam 141 are hung and connected below the load beam 13 by slings 142.

The buried high-voltage cable 11 is sleeved in the power grid 111, the bottom of the power grid 111 is fixed on the pocket bottom beam 141, and the pocket bottom beam 141 is made of 20 a-type I-shaped steel, namely the bottom of the power grid 111 is made of 20 a-type I-shaped steel. The hanging connection mode adopts a 5T chain block, the 5T chain block is arranged on the sling 142, the top of the bearing beam 13 is provided with hanging points, and the hanging points are arranged at intervals of 1000mm at equal intervals to form a power calandria hanging and reinforcing system.

5. As shown in fig. 8 and 9, the foundation pit supporting structure 15 is a foundation pit supporting structure of the underground pipe gallery to be constructed below the power grid pipe, and is arranged in a construction foundation pit of the underground pipe gallery to be constructed. The foundation pit supporting structure 15 comprises obliquely inserted combined steel sheet piles which are arranged at two ends of a penetrated section of the buried high-voltage cable 11 and are positioned on the inner side of the bearing buttress 12, each group of obliquely inserted combined steel sheet piles comprises a first obliquely inserted steel sheet pile 151 and a second obliquely inserted steel sheet pile 152, and the first obliquely inserted steel sheet pile 151 and the second obliquely inserted steel sheet pile 152 are gradually and obliquely drawn together from top to bottom.

Further, insert combination steel sheet pile to one side and arrange and keep apart certain distance with utility tunnel 10 along the axial of utility tunnel 10 that waits to be under construction (insert combination steel sheet pile to one side and laminate the foundation ditch lateral wall setting of utility tunnel that waits to be under construction).

Specifically, the foundation pit support below the power grid 11 adopts a mode of obliquely inserting steel sheet piles at the rear, and 20mm steel plates are adopted as mud blocking plates 153 in the foundation pit and welded on the obliquely inserted combined steel sheet piles to block collapse of foundation pit side slopes at two sides. The drainage of the foundation pit adopts a pit top drainage ditch and an in-pit open water pumping drainage mode.

The reinforcement construction method of the reinforcement structure according to the above embodiment will be described in further detail with reference to the drawings.

The protection and reinforcement of the underground comprehensive pipe gallery penetrating through the buried high-voltage cable mainly comprises the following steps:

step 101, arranging bearing buttresses at two ends of a penetrated section of a buried high-voltage cable, wherein the bearing buttresses comprise constructing cast-in-place piles at two sides of the buried high-voltage cable, and constructing cover beams at the tops of the cast-in-place piles at the two ends after construction;

102, hoisting bearing beams at the tops of the capping beams of the bearing buttresses at two ends;

103, excavating a working pit at the penetrated section of the buried high-voltage cable to the lower part of the buried high-voltage cable;

104, hanging and hanging the reinforcing structure by using the working pit, wherein the hanging and hanging method comprises the steps that two ends of a pocket bottom beam are hung and connected below a bearing beam by using a sling, and the pocket bottom beam stretches across two sides of the bottom of the buried high-voltage cable;

and 105, arranging foundation pit supporting structures at two ends of the penetrated section of the buried high-voltage cable, wherein obliquely inserted combined steel sheet piles are arranged at two sides of the buried high-voltage cable at the two ends, each obliquely inserted combined steel sheet pile comprises a first obliquely inserted steel sheet pile and a second obliquely inserted steel sheet pile and is positioned on the inner side of the bearing buttress, and the first obliquely inserted steel sheet pile and the second obliquely inserted steel sheet pile are gradually obliquely drawn together from top to bottom.

The following will explain the above construction method with reference to fig. 10 and the concrete construction:

firstly, preparation of construction

Site cleaning and dismantling preparation: and (4) manually cooperating with machinery to remove the stacking materials such as the templates, the frame pipes, the to-be-used reinforcing steel bars and the like at the periphery of the foundation pit, and stacking the materials placed at the periphery of the construction site to an appointed place.

And (3) measuring and placing points: and (5) utilizing a total station to carry out cast-in-place pile construction coordinate point placement. Leveling and excavating a field, placing a steel casing and a mud pit, and impacting drilling equipment, a casing and the like to reach specified positions.

Second, construction of punching cast-in-place pile

The construction process is shown in FIG. 11, and the construction method comprises the following steps:

(1) and (3) measuring and placing points: and (4) measuring the central position of each pile position by using a total station according to the measurement control point, and placing the pile protector.

(2) Embedding a steel pile casing: when the drilling depth reaches about 3m, the drill (hammer) is lifted and the casing (protective cylinder) is put down. The deviation between the center of the pile casing and the center of the pile position is not more than 50 mm. The protective cylinder is made of a steel plate with the diameter of 5mm in a rolling mode, and the inner diameter of the protective cylinder is 200mm larger than the diameter of the drill bit. The embedding depth of the pile casing is generally 2.0-4.0 m, the height of the pile casing is 300mm higher than the ground, the mud surface in the hole is 1m higher than the underground water level to ensure no collapse, and the upper part of the pile casing is provided with a mud overflow hole. After the casing is in place, the top elevation is measured. The bottom and the periphery of the pile casing are tamped by clay to ensure that slurry does not leak.

(3) Installing a drilling machine: before the drilling machine is in place, the ground must be leveled, and the drilling machine needs to be placed flatly and stably, so that the drilling machine is not inclined or moved in the construction process.

(4) Preparing slurry: the preparation of the slurry needs to select high-plasticity clay or bentonite. The slurry wall is to meet the following regulations:

a. during construction, the mud surface in the pile casing is higher than the underground water level by more than 1.0m, and when the pile casing is influenced by water level fluctuation, the mud surface is higher than the highest water level by more than 1.5 m.

b. In the process of cleaning the hole, the slurry is continuously replaced until the concrete is poured.

c. Before concrete is poured, the specific gravity of the slurry within 500mm of the hole bottom is less than 1.25; the sand content is less than or equal to 8 percent; the viscosity is less than or equal to 28 s.

d. In soil layers which are easy to cause mud leakage, measures for keeping the hole wall stable are taken.

e. The waste slurry and slag are treated according to the relevant regulations of environmental protection.

(5) And (3) impact hole forming: when the impact drill is adopted, the upper part is impacted by a low hammer, the impact can be changed into medium-high hammer impact when 2-3m is below the ground, the impact by the low hammer is adopted when a stratum is changed, and the primary hole inclination is checked to prevent the hole deviation.

(6) Final hole, cleaning hole

Firstly, when the drilling hole reaches the designed depth, the drilling is stopped, a supervision engineer is required to make a hole for inspection, the hole position, the hole diameter, the hole depth, the verticality and the like are measured, and the hole cleaning is started after approval.

Secondly, no mud block is left in the hole after the hole is cleaned for the first time, and the relative density reaches about 1.2.

Thirdly, controlling the specific gravity of the slurry at the position of 0.2-1 m of the hole bottom after hole cleaning to be about 1.1, wherein the sand content of the slurry is less than or equal to 8 percent, and the viscosity is less than or equal to 28 s.

Fourthly, the sediment friction pile at the bottom of the hole after hole cleaning is not larger than 150mm, and the rock-socketed pile is not larger than 50 mm. Before underwater concrete is poured, the thickness of the sediment must be measured again, if the sediment thickness exceeds the specification, the hole must be cleaned again, and after the sediment thickness is qualified, the underwater concrete can be poured.

Fifthly, when cleaning the hole, keeping the water level in the hole higher than the underground water level by 1.5-2.0 m so as to prevent the hole from collapsing.

(7) Safety reinforcing cage

Firstly, the diameter, the number and the spacing of main reinforcements and stirrups for manufacturing the reinforcement cage meet the requirements of design drawings and technical specifications. The reinforcement cage is divided into an anchoring section (extending into the bent cap by 0.5m) and a standard reinforcement section, and blanking and binding are carried out according to the actual hole depth carefully during construction.

Secondly, manufacturing the reinforcement cage in a segmented mode, wherein each pile foundation reinforcement cage is generally hoisted in two sections, when the site is limited, the pile foundation reinforcement cage is hoisted in sections of 8-12 m, and rib welding is adopted for hoisting and lapping.

Thirdly, the diameter of the reinforcement cage meets the design requirements, and the following requirements are met: the outer diameter should be 140mm smaller than the designed diameter of the bore hole, and the inner diameter should be more than 100mm larger than the outer diameter at the catheter joint.

And fourthly, when the reinforcement cage is hoisted, measures are taken to prevent torsion and bending, the reinforcement cage is hoisted into the hole by using a crane, cross reinforcing ribs are arranged at the hoisting point, the long reinforcement cage is hoisted in sections, and the wellhead is welded.

And fifthly, immediately hoisting the reinforcement cage after hole cleaning, and fixing the reinforcement cage on the wellhead casing to ensure that the reinforcement cage does not float in the pouring process. When the steel reinforcement cage is installed, the steel reinforcement cage is aligned to the hole position, the crane is straight and stable, and sinks slowly, so that the hole wall is prevented from being damaged.

Sixthly, in order to ensure the thickness of the protective layer of the reinforcing steel bar, a positioning reinforcing steel bar ring is arranged.

And seventhly, after the steel reinforcement cage is installed and self-inspection is qualified, reporting to a supervision engineer to carry out hidden engineering inspection and acceptance, and pouring underwater concrete in time, wherein the interval time is not more than 4 hours so as to prevent precipitation and hole collapse.

(8) Placement catheter

The guide pipe is made of seamless steel bars, the wall thickness of the guide pipe is not less than 3mm, and the pipe diameter is 200-250 mm. Duct sectional length: the length of the bottom tube is not less than 4m, each section in the middle is 2m long, and the two sections on the upper part are 1m respectively. The sections are connected by a flange joint or a double-screw thread quick joint.

Secondly, before the guide pipe is used, the guide pipe is firstly assembled and pressure tested on the ground, the pressure of the pressure test is 0.6-1.0 Mpa, and then the guide pipe is lifted by a crane for placement.

And thirdly, in order to prevent the flange from hanging the steel reinforcement cage when the guide pipe is lifted, a conical protective cover is arranged.

Preparing a storage hopper and a waterproof bolt matched with the guide pipe, wherein the waterproof bolt is prefabricated by concrete.

(9) Pouring underwater concrete

Firstly, the underwater poured concrete has good workability, the mixing proportion of the concrete is determined through tests and approved by supervision engineers, and the slump is preferably 180-220 mm. The fine aggregate is preferably clean medium and coarse sand with good gradation, and the sand rate in the concrete mixture is controlled to be 40-50%. The coarse aggregate is preferably broken stone with the particle size of 5-40 mm. The underwater concrete is preferably added with additives (water reducing agent, retarder and the like), and the adding amount is determined by tests.

Secondly, when the pouring is started, the hanging position of the water-proof bolt is close to the mud surface, the distance between the guide pipe and the hole bottom is preferably that the water-proof bolt can be smoothly discharged, and the distance is generally 0.3-0.5 m.

Thirdly, the storage hopper is required to have concrete storage capacity enough for embedding the bottom end of the guide pipe into underwater concrete for more than 1m depth at one time before irrigation.

And fourthly, lifting and disassembling the guide pipe in due time along with the rising of the concrete, wherein the bottom end of the guide pipe is embedded below the concrete surface and is generally kept 2-4 m, is not more than 6m and not less than 1m, and the bottom of the guide pipe is strictly lifted out of the concrete surface to avoid pile breakage.

Fifthly, in the process of underwater concrete pouring, a specially-assigned person should measure the buried depth of the guide pipe and fill in the underwater concrete pouring record.

Sixthly, the underwater concrete pouring is carried out continuously without relaying, so that strict construction organization design and auxiliary measures are needed before pouring, and once machine tool failure or power failure, conduit blockage and the like occur, effective measures are immediately taken and simultaneously records are made.

Seventhly, the guide pipe is lifted without touching and hanging the reinforcement cage. When the concrete surface rises to 3-4 m in the reinforcement cage, the guide pipe is lifted, so that the bottom of the guide pipe is higher than the bottom end of the reinforcement cage, and the reinforcement cage is prevented from floating upwards.

And controlling the pouring amount of the final concrete to ensure that the pile top elevation meets the design requirement after the top surface of the poured concrete meets the condition of chiseling out the laitance layer, thereby ensuring the quality of the pile body. Generally, the height should be controlled to be about 0.5-1.0 m above the designed pile top height.

(10) Pipe-pulling and pile-cutting head

Firstly, after the underwater concrete pouring is finished, the guide pipe is lifted out of the pile, the guide pipe is disassembled section by section, the pipe section and the connecting part are washed clean by water, then the oil is applied, and the pile is placed and kept.

And secondly, manually removing the super-poured concrete. After the concrete of the pile body is completely poured for 6 hours, the concrete which is poured more than once can be manually dug until the height is 20cm higher than the designed elevation of the pile top, and the 20cm concrete is chiseled when the concrete of the bearing platform is poured. And (4) paying attention to not disturbing the pile body concrete.

The following scheme can be adopted when a karst cave is encountered during construction:

when the karst cave is shallow in buried depth, small in range and small in height, and the karst cave is filled with filler or partial filler, and the karst cave is not communicated, so that large-scale slurry leakage and hole collapse can not be caused when the karst cave is punched, the slurry can be timely supplemented when the karst cave is punched, the water level height in the hole can be kept, meanwhile, 1:1 small-diameter stone chips and bagged soil are put into the hole, and the throwing filler is squeezed into the wall of the karst cave hole or cracks of the karst cave by slow drilling to block the karst cave, and when the effect is not obvious, bagged cement is added until the slurry surface in the hole is stable and slurry leakage and hole collapse are avoided, and then the hole is slowly drilled and enters a relatively stable layer 1.5m below the karst cave region.

Secondly, when the karst cave is deeply buried, the karst cave is large and is not filled, but is not communicated, the steel casing retaining wall with the diameter of 100cm and the wall thickness of not less than 5mm is rapped on the basis of the scheme I during construction, and the length of the steel casing is that the steel casing is rapped to the rock surface.

And thirdly, when the karst cave is very large and difficult to fill, sinking the steel casing with the diameter of 100cm to the rock surface elevation by using a vibration hammer before entering the rock, adopting impact drilling for auxiliary drilling in the sinking process, punching the pile foundation (with the aperture of 90cm) by using the impact drilling before reaching the karst cave, firstly filling slurry into the hole until the condition in the hole is stable after entering the karst cave, then adopting the steel casing with the diameter of 90cm and the wall thickness of not less than 5mm in the original steel casing for follow-up, continuously lengthening the steel casing until the steel casing penetrates through the karst cave to reach the bottom plate of the karst cave, and then changing the diameter of the original pile foundation for rock-socketed drilling construction.

Construction of third, capping beam

The construction process is shown in FIG. 12, and the construction method comprises the following steps:

(1) pile top concrete chiseling and pile head cleaning

And chiseling and removing the concrete of the pile head of the over-poured bored pile according to the mark of the pile head of each pile. When the pile head is chiseled off, only chisels towards the pile core from the horizontal direction, can not chisels downwards from the pile head to avoid the pile head to become the tapered, can not move the reinforcing bar in the bored pile about simultaneously. After the pile head drills to the height above 5cm of the cover beam bottom, loose concrete blocks are removed, the chiseling surface is blown and sprayed completely by an air pump, cushion concrete is poured, and reinforcing steel bars can be bound after quality inspectors accept the concrete.

(2) Construction laying-out bent cap central line

After the cushion concrete construction is finished, the capping beam central line control points are encrypted and led to the pile top, the capping beam central points are released, and all points are connected into a line to be used as the capping beam construction control central line.

(3) Binding of reinforcing steel bars

a. Straightening hole pile steel bars: and according to the center line of the bent cap, dividing a bent cap side line from left to right. If the reinforcing steel bars of the cast-in-situ bored pile deviate from the side line of the capping beam or influence the installation of the template, breaking the reinforcing steel bars into the capping beam by using steel pipe tongs; if the reinforcing steel bars cannot be broken into the bent cap, the size of the bent cap can be enlarged properly. If some steel bars are not straight, the steel bars are straightened by using a steel pipe clamp.

b. Manufacturing and installing steel bars: the bent cap reinforcing steel bar is carried to the on-site installation after processing is accomplished in the processing field, notices the size of putting of reinforcing steel bar and the position of main muscle during the installation, and the main muscle distributes in the both sides of roof beam and upper and lower face, strictly according to design size and interval installation. Steel bar anchoring and lapping are carried out according to design requirements, a main steel bar adopts a lap welding connection mode, the length of a welding seam of double-sided lap welding is not less than 5d (d is the diameter of the steel bar), when double-sided welding cannot be carried out, single-sided welding can be adopted, the length of the welding seam of the single-sided welding is not less than 10d (d is the diameter of the steel bar), the thickness of the welding seam is not less than 0.3d, the width of the welding seam is not less than 0.8d (d is the diameter of the steel bar), the welding seam is full, and the axes of the main steel bar are ensured; and the main reinforcement of the cast-in-situ bored pile is arranged on the inner side of the steel reinforcement of the cover beam. The crossed joint of the main reinforcement and the stirrup can be bound in a plum blossom shape or spot welded, so that the main reinforcement and the stirrup can be effectively and firmly connected. The capping beam is constructed in sections, and the joint part of each section is provided with a reserved connecting steel bar.

(4) Formwork construction

Firstly, template construction: the capping beam template consists of side plates, wooden shelves, horizontal braces, inclined braces, wooden piles and the like. The side mould is formed by nailing a long strip wood plate with a vertical wood baffle. The horizontal brace and the diagonal brace are nailed between the wood pile and the wood block.

And secondly, during construction, popping up a side line of the cover beam on the base mortar leveling layer, aligning the side mold to the side line, vertically erecting, correcting the top surface of the side plate to be horizontal by using a horizontal ruler, and then firmly nailing by using an inclined strut and a flat strut. If the bent cap is longer, the end templates at the two ends of the bent cap are firstly installed, after correction, the through line is pulled at the upper opening of the side mold, and then the side plate is installed according to the through line.

The bottom of the side mold is required to be finished and leveled, so that the bottom of the template is ensured not to leak slurry, and the quality of concrete is ensured; the fixing of the foot pressing strips adopts reinforcing steel bars with the length of 50cm, and one reinforcing steel bar is arranged at intervals of 50 cm.

Fixing the steel pipe: fixing the middle part of the side die by adopting double steel pipes, fixing the steel pipes on the template by using iron, and then fixing the upper part of the steel pipes by using the steel pipes and fasteners in a pulling manner; the side surface of the template is fixed by adopting an inclined strut and a horizontal strut which form an angle of 45 degrees with the ground, the bottom of the template is provided with a steel bar, and the steel bar is driven into the ground to be not less than 30 cm.

Dismantling the template: after the strength of the concrete reaches 50%, the side mold can be dismantled after 24 hours; the form is removed carefully without damaging the concrete on the beam surface.

(5) Pouring of concrete

The concrete adopts commercial concrete, is carried to the cooperation chute of pouring the place by the transport vechicle for the concrete mixing station and pours, pours and adopts the horizontal layering's mode of pouring, notices the layering thickness, and every layer thickness is not more than 30 cm. The method is characterized in that an insertion vibrator is adopted for vibrating, points are distributed according to rows, and the distance between the distributed points is not more than 1.5 times of the effective vibrating radius of a vibrating rod. The surface vibrator is shifted by a pitch such that the vibrator plate can cover the vibrated portion by about 100 mm. The vibrating time and distance can be mastered at any time in the vibrating process, and the situations of over-vibration and leakage vibration are prevented. The vibration is controlled according to the mark that the concrete is thick, the surface is flat, no air bubble emerges, the concrete surface does not sink any more and is compacted, and the concrete cannot be vibrated within 1.5 to 24 hours after being compacted.

The distance between the vibrating rod and the template is noticed in the vibrating process, and the vibrating rod is prevented from colliding with the template to influence the appearance quality. In the pouring process, a specially-assigned person is arranged to observe the position of the template, so that the template is prevented from running and expanding, and reinforcement measures are taken in time when problems are found.

After the pouring is finished, the concrete is manually folded, and the surface is ensured to be flat and smooth.

And after the construction of the cover beam concrete is finished, timely maintaining for 14 days, and carrying out covering watering maintenance according to weather conditions.

(6) Form removal

And (3) stripping conditions: the mould can be torn open after the tectorial membrane concrete intensity reaches 2.5MPa, generally pours into 1 ~ 2 days that finish and just can the removable mould, issues the removable mould notice back by project department's experiment and can tear open the mould.

And (3) removing the mold: dismantling adjustable support → dismantling cross brace and vertical brace → dismantling formwork → removing formwork and carrying out rust-proof treatment → stacking of formwork, support and the like → maintenance of capping beam

The mold stripping requirement is as follows:

firstly, if the inner side of the cover has protrusions after the form removal is finished, the inner side of the cover needs to be cleaned and leveled in time, the concrete needs to be reported in time when the concrete has defects, and the concrete is treated according to requirements after agreement so as to facilitate the next procedure construction.

And secondly, care is needed to be taken when the form is removed, and the corner of the capping beam is prevented from being touched.

And thirdly, the joint of the removed template and the lower section is subjected to scabbling treatment in time.

Fourthly, after the template is removed, the template is orderly stacked in time, and after the template is removed, the site is cleaned in time.

Fourthly, manufacturing and installing bearing steel beams

The construction process sequence:

material acceptance → lofting and blanking → assembling → component welding → component mounting → quality inspection and acceptance → handing over.

(II) construction method

(1) And (4) material acceptance: the steel material should have a quality certificate and meet design requirements. The materials which arrive are qualified by self-inspection and then should be reported to supervision for field inspection, and the materials which arrive after the inspection can be used for engineering.

(2) Lofting and blanking:

firstly, the lofting platform is required to be flat and stable, and the surface is free from welding beading and sundries;

and secondly, reserving machining allowance such as cutting allowance and welding shrinkage allowance according to the construction process requirement for lofting and material marking, avoiding the position of a hole on a rod piece joint, and checking the material and specification during material marking.

And thirdly, after the lofting work is finished, a sample plate can be manufactured after the quality inspection is qualified. The sample plate and sample rod for mass production of parts should be frequently tested again.

Loft and template size tolerance are shown in the following table:

item	Tolerance deviation
		Parallel line distance and segment size	±0.5mm
Width and length	±0.5mm
		Diagonal length difference	±1.0mm
Pitch of holes	±0.5mm
		Angle of rotation	±20`

The allowable deviation of direct material marking of the steel ruler is shown in the following table

Sixthly, removing rust, dirt and the like in the cutting area before gas cutting, removing slag and splashes by using a polishing machine after gas cutting, and cutting the blanking of the small angle steel and the flat steel by using a grinding wheel cutting machine. The cut surface of the steel product has no cracks, slag inclusion, delamination and the like.

Allowance for gas cutting is shown in the following table

(3) Assembling and welding:

firstly, before welding, a welding operation instruction book is formulated, and a welding process card is filled in. One welder is carried about by one person for each welding process card, and technicians, quality personnel and supervision engineers check the process standard execution condition on site.

Secondly, the welding rod is baked according to the requirements of the welding operation instruction.

And thirdly, the welder should have the qualification certificate of the corresponding welding project to ensure the certification to be on duty.

And fourthly, removing mud and floating rust within 50mm of each of two sides of the groove of the welding joint.

Before welding, the component should be leveled and stabilized to prevent deformation during welding.

Sixthly, when the manual electric arc welding is carried out, the wind speed is more than 8m/s, and the welding is stopped under the rain and snow environment.

Seventhly, a J422 welding rod is adopted when the steel material made of the material Q235B is welded, and the welding sequence should be correctly selected in order to reduce welding deformation. According to the condition of the component, the deformation can be controlled by adopting methods such as symmetrical welding, step-back welding, intermittent welding and the like.

(4) Component transportation and installation

Firstly, transporting steel members by adopting a 25-ton truck crane and a 20-ton truck flat car for hoisting, unloading and transporting;

selecting a crane: and hoisting the small components in place by using a 25-ton truck crane.

(5) Mounting of

Firstly, before installation, the strength and stability of the member which is easy to deform during hoisting are checked. The construction technical requirements of the steel structure for temporary reinforcement are the same as those of formal construction.

Secondly, the following conditions are required before the steel structure is installed:

a. the design files are complete and are already reviewed;

b. the foundation is accepted and qualified;

c. the components are complete, marked obviously, the quality is qualified, and the components are provided with a detailed table, a product quality certificate, a preassembly record and a test report of the anti-sliding coefficient of the friction surface of the high-strength bolt;

d. the construction site planning should conform to the industry approved construction organization design or construction scheme;

e. the materials involved in installation are well prepared;

f. the mechanical equipment has good running condition;

g. the water, electricity and gas sources can meet the construction requirements and ensure the continuity of the construction requirements.

And thirdly, in the process of installing the steel structure, the steel structure is aligned in time strictly according to the construction procedure. No further components should be mounted on the component that has not been aligned.

Fifth, suspension reinforcement system construction

Working pit excavation

Within 1.7m of each side of the power grid, a working pit 16 is excavated to a depth of about 0.8m, as shown in fig. 7. The working pit is excavated by a small machine, and the electric power grid 111 is prevented from being touched during excavation. The bottom of the working pit is manually cleaned when the foundation is excavated, and the bottom of the pit is at least 0.2m-0.3m lower than the bottom surface of the pipe arrangement.

(II) 2, placing and suspending the pocket bottom beam 141

Rectangular cavities of 0.25m x 0.25.25 m are dug at the designated positions (vertical projection positions of top steel beam cross beams) at the bottom of the power grid 111, the cavities are tightly attached to the grid bottom, and cushion concrete below the exposed grid bottom is removed during construction. In the engineering, 20 a-shaped I-steel is used as a bottom pocket bottom beam 141, the I-steel is placed to the bottom of a calandria by adopting a manual hammering method, the I-steel pocket bottom beam 141 is lifted by using 5T chain hoists at two sides, and the next pocket bottom beam 141 can be constructed after the suspension is firm.

Sixth, supporting construction of foundation pit

And after suspension reinforcement is finished and acceptance is qualified, carrying out foundation pit supporting construction, and preventing the substrate sludge from bulging due to the fact that steel sheet piles cannot be inserted and driven below the power grid pipe and the steel sheet piles on two sides are inclined at a certain angle to prevent water.

And the side wall of the foundation pit below the power grid is welded with a steel plate with the thickness of 20mm to temporarily block the sludge from flowing out. The foundation pit drainage is realized in a mode of pumping and draining open water in a foundation top cut drainage ditch and a pit, and a foundation pit supporting plane layout diagram and a foundation pit supporting section diagram are shown in fig. 8 and 9.

The embodiment of the invention has the following technical effects:

(1) convenient technical application, and safe and stable protection and reinforcement new technology

1) The steel structure construction is not influenced by the environment season, and the steel structure member is convenient for manufacturing in the factory, assembling in the building site.

2) The finished steel structural member has high precision, high production efficiency, high construction site assembling speed and short time consumption.

3) The method solves the problems that the 110KV buried high-speed rail special power supply line is not changed and is not powered off, ensures that the safety of the 110KV buried high-voltage cable and the normal operation of the high-speed rail are not influenced by the shadow line, simultaneously ensures that the construction of the urban underground comprehensive pipe gallery is not influenced by the 110KV buried high-voltage cable, shortens the construction period and has remarkable economic benefit and social benefit.

(2) The steel structure is adopted, the economic and the construction period are shortened, and the environment is protected

1) The steel structure system has light dead weight which is about half of a concrete structure, can greatly reduce the manufacturing cost and has short construction period.

2) Through hanging in midair the method with concrete "stool formula" portal to steel construction "stool formula" portal and hanging in midair the method and contrast, adopt the steel construction, the quantity of sand, stone, ash that has significantly reduced during the construction, used material is mainly green, and the material can 100% be retrieved, and when demolising, most material can be retrieved and recycled, can not cause rubbish, really accomplishes green pollution-free.

3) And the field welding assembly is adopted, so that the construction period is shortened, and the working efficiency is improved.

It should be noted that the structures, ratios, sizes, and the like shown in the drawings attached to the present specification are only used for matching the disclosure of the present specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions of the present invention, so that the present invention has no technical essence, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The utility model provides a wear utility tunnel protection reinforcing system on buried high tension cable which characterized in that includes:

the foundation pit supporting structure comprises obliquely inserted combined steel sheet piles which are arranged at two ends of a penetrated section of the buried high-voltage cable and are positioned on the inner side of the bearing buttress, each group of obliquely inserted combined steel sheet piles positioned at the same end of the penetrated section of the buried high-voltage cable comprises a first obliquely inserted steel sheet pile and a second obliquely inserted steel sheet pile, and the first obliquely inserted steel sheet pile and the second obliquely inserted steel sheet pile are gradually and obliquely drawn together from top to bottom;

the obliquely inserted combined steel sheet piles are arranged along the axial direction of the underground comprehensive pipe gallery to be constructed and are separated from the underground comprehensive pipe gallery by a certain distance, and the obliquely inserted combined steel sheet piles are arranged by being attached to the side wall of a foundation pit of the underground comprehensive pipe gallery to be constructed; gaps which are not closed up between the first obliquely inserted steel sheet pile and the second obliquely inserted steel sheet pile below the buried high-voltage cable are sealed by mud blocking plates; the mud blocking plates are welded on the opposite inner sides of the first inclined steel inserting plate pile and the second inclined steel inserting plate pile at the two ends;

the cast-in-place pile adopts an end-bearing pile and an impact type hole forming mode and enters the bedrock;

the following scheme is adopted when the cast-in-place punched pile is constructed and meets a karst cave:

firstly, when the karst cave is shallow in burial depth, small in range and small in height, and the karst cave is filled with fillers or partial fillers, when the karst cave is not communicated, large-scale slurry leakage and hole collapse cannot be caused when the karst cave is punched, timely slurry supplement is adopted when the karst cave is punched, the water level height in the hole is kept, meanwhile, 1:1 small-diameter slate and bagged soil are put into the hole, the throwing fillers are squeezed into the hole wall of the karst cave or cracks of the karst cave by slow drilling to block the karst cave, and the bagged cement is added when the effect is not obvious until the slurry surface in the hole is stable and does not leak slurry and collapse, and then the karst cave area is slowly advanced to enter a relatively stable layer at the lower part;

secondly, when the karst cave is buried deeply, the karst cave is large and is not filled, but is not communicated, the steel casing wall is vibrated on the basis of the first scheme during construction, and the length of the steel casing is equal to the length of the rock surface;

when the solution cavity is very difficult to fill, the steel casing is sunk to the rock surface elevation by a vibration hammer before entering the rock, the sinking process adopts the impact drill to assist in drilling, the pile foundation is punched by the impact drill before reaching the solution cavity, after the solution cavity is entered, slurry is filled into the hole until the condition in the hole is stable, then the steel casing with smaller diameter is adopted in the original steel casing to follow up, the steel casing is continuously lengthened until the steel casing passes through the solution cavity to reach the solution cavity bottom plate, and the original pile foundation diameter is changed into the original pile foundation diameter to carry out rock embedding drilling construction.

2. The underground utility tunnel protection and reinforcement system of wearing on buried high voltage cable of claim 1, characterized in that: each bearing buttress comprises two cast-in-place piles which are arranged along the axial direction of the underground comprehensive pipe gallery to be constructed.

3. The underground utility tunnel protection and reinforcement system of wearing on buried high voltage cable of claim 1, characterized in that: the buried high-voltage cable is arranged in a cable duct bank in a penetrating mode, and the cable duct bank is fixed on the pocket bottom beam.

4. The utility model provides a wear utility tunnel protection reinforcement method on buried high tension cable which characterized in that includes the step:

arranging foundation pit supporting structures at two ends of a penetrated section of the buried high-voltage cable, wherein obliquely inserted combined steel sheet piles are arranged at two sides of the buried high-voltage cable at the two ends, each group of obliquely inserted combined steel sheet piles at the same end of the penetrated section of the buried high-voltage cable comprises a first obliquely inserted steel sheet pile and a second obliquely inserted steel sheet pile and is positioned on the inner side of the bearing support pier, the obliquely inserted combined steel sheet piles are arranged along the axial direction of the underground comprehensive pipe gallery to be constructed and are separated from the underground comprehensive pipe gallery by a certain distance, the obliquely inserted combined steel sheet piles are attached to the side wall of a foundation pit of the underground comprehensive pipe gallery to be constructed, and the first obliquely inserted steel sheet piles and the second obliquely inserted steel sheet piles are gradually and obliquely close from top to bottom;

after the construction is finished, the method also comprises the following steps: a gap which is not closed between the first obliquely inserted steel sheet pile and the second obliquely inserted steel sheet pile below the buried high-voltage cable is sealed by a mud blocking plate;

5. The underground comprehensive pipe gallery protection and reinforcement method for the buried high-voltage cable, which is characterized in that: when the bored concrete pile is constructed, the constructed bored concrete pile is higher than the designed elevation of the pile top by a distance, the bored concrete pile is chiseled off the distance before the capping beam is constructed, and the capping beam is constructed at the top of the bored concrete pile after the pile top is chiseled off.

6. The underground comprehensive pipe gallery protection and reinforcement method for the buried high-voltage cable, which is characterized in that: the buried high-voltage cable is arranged in the cable duct bank in a penetrating mode, and the cable duct bank is fixed on the pocket bottom beam when the pocket bottom beam is connected in a hanging mode.