CN107587528B - It is a kind of to protect the design and construction method across the underground high voltage cable box culvert of foundation pit - Google Patents
It is a kind of to protect the design and construction method across the underground high voltage cable box culvert of foundation pit Download PDFInfo
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Abstract
The design and construction method of underground high voltage cable box culvert the present invention provides a kind of protection across foundation pit, comprising: collect cable box culvert data, determine cable box culvert globality；Surveying and locating determines cable box culvert and fender post position；Cable box culvert soil at both sides is excavated, steel I-beam is preset；It draws except cable box culvert lower recess soil, and applies connecting rod；Triangle square steel frame is welded in each connecting rod two end；Lifting i-beam frame simultaneously anchors；It after concrete hardening, draws except the soil body between groove, and the welded reinforcement mesh sheet between the lower link of cable box culvert, and gunite concrete anchors.The present invention solves the problems, such as to be embedded with underground high voltage cable box culvert on constructing tunnel channel, more effectively guarantee the safety of cable box culvert with I-shaped bracing members, avoid the relocating work of cable box culvert, the duration has been saved for entire work progress, construction efficiency has been improved, save removal charge, reduce construction cost, and has alleviated the influence to surrounding resident.
Description
Technical field
The present invention relates to a kind of method of construction engineering technical field, it is specifically a kind of with cast-in-place support to cross over base
The design and construction method that the underground high voltage cable box culvert in hole is protected.
Background technique
In recent years, with the rapid growth of the quickening of Urbanization in China and urban population, urban ground traffic system
Increasingly congestion, urban track traffic are rapidly developed in each big and medium-sized cities.In the construction of urban track traffic, often
Encounter the City Buried Pipelines such as underground high voltage cable.In the construction process, part unit in charge of construction is to work to tight deadlines to construct by force, and pole has
The City Buried Pipelines such as underground high voltage cable may be forced large deformation occur or generate destruction.And the buried pipes such as underground high voltage cable
Line is the important infrastructure for ensureing city operations, especially underground high voltage cable, and importance is high, is influenced big.And underground high-voltage
Cable usually occurs at track traffic station foundation pit and constructing tunnel channel, it is difficult to avoid, it is necessary to be protected.At present
Safeguard measure to underground high voltage cable is usually to cut to change underground utilities, or by underground high voltage cable temporary shift to widened road
Face, after then move to original position after the completion of engineering.But not only cost is high for the migration position that changes of underground high voltage cable, time-consuming, delays work
Phase, and seriously interfere the normal life of resident nearby.If can be protected in underground high voltage cable original place, guarantor will be greatly simplified
Shield measure reduces the waste of manpower financial capacity, mitigates the influence to society.Therefore, a kind of setting for high-tension cable in-situ conservation is invented
Counting construction technology has highly important engineering application value.
By finding to existing patent retrieval, the existing in-situ conservation construction method to high-tension cable relates generally to cable
The suspension protection method of box culvert, Chinese Patent Application No. 201410853049.1, application publication number are 104518473 A of CN,
Patent name are as follows: cable box culvert pipe line suspension protection structure and method, the patent readme are as follows: " present invention passes through in cable box culvert
Crossbeam is longitudinally shelved in the top of the stake of two sides in parallel, and several top fashioned iron are arranged in interval on the crossbeam, excavates box culvert two sides
The soil body is laid with steel plate in box culvert bottom, and bottom fashioned iron is arranged in corresponding top fashioned iron, then connects top and bottom fashioned iron with wirerope
Box culvert is suspended in midair." set in parallel however, having beside the requirement of cable box culvert guard method described in invention box culvert position
That sets shelves crossbeam, the protection of cable box culvert and is not suitable on the constructing tunnel channel for not shelving crossbeam, meanwhile, the skill
Art carries out suspension protection using wirerope, suspends in midair for a long time under big load and is easy to make wirerope that creep occurs, and scene is applied
Since transporting equipment frequently enters and leaves scene under work state, the careless slightly wirerope that may encounter suspension apparatus keeps box culvert left
The right side is rocked, and wirerope is then it is possible that unbalance stress, and local stress increases, and is broken, be may cause accident when serious,
Construction personnel's life is endangered, the wealth of society is wasted.
Summary of the invention
The present invention is directed to the above-mentioned deficiency of the prior art, propose it is a kind of it is simple, convenient, and reliable with cast-in-place support to leap
The design and construction method that the underground high voltage cable box culvert of foundation pit is protected is calculated with strict design, for applying for rail traffic
The protection problem of underground utilities proposes rationally reliable solution in work, avoids the extension of construction period, construction cost
The adverse effect for increasing and constructing to society.
What the present invention made to be achieved through the following technical solutions:
The present invention provides a kind of design and construction method protected and cross over the underground high voltage cable box culvert of foundation pit, including following step
It is rapid:
The first step collects cable box culvert related data, determines cable box culvert globality；Include:
(1) according to the related data of cable box culvert, cable box culvert weight G is determined；
(2) according to cable box culvert weight G, size and cable box culvert concrete strength, if determine do not apply safeguard measure,
Maximal bending moment M when cable box culvert suspends in midair naturallymaxWith the moment of inertia I；
(3) the maximum (normal) stress σ when suspention of cable box culvert is determinedmax, and compare the allowable tensile stress of cable slab culvert concrete
[σ] is obtained according to " Code for design of concrete structures " (GB 50010-2010), is checked the globality intensity of cable box culvert；It is described
σmaxIt is determined by following formula:
For [σ] < σmaxIf expression does not apply safeguard measure, suspends cable box culvert naturally in midair, cable box culvert can be by broken
Bad, the globality of cable box culvert is bad, needs to carry out supporting in advance；
Second step, surveying and locating determine cable box culvert and fender post position；
That is: it using total station according to construction drawing, determines cable box culvert and is located at foundation pit both sides, cable box culvert two sides and most
Close to four fender post positions of cable box culvert, checked by least two people；Selection indicates contour line on the profile of cable box culvert
8~12 points mark, filament is pulled between label, and mark in fender post center, is gone along with sb. to guard him adjacent two
Filament is pulled between stake, and is sprinkled with lime on ground along filament；
Third step excavates cable box culvert soil at both sides, presets steel I-beam；Include:
(1) with the cable box culvert soil at both sides in excavator excavation pit apart from box culvert 50cm or more；
(2) manual type is used, the remaining whole soil bodys in excavation pit inner cable box culvert two sides form cable duct；
(3) manual type is used, four grooves is excavated in foundation pit side-wall, four grooves is made to be located on foundation pit side four
Fender post far from box culvert side and closely fender post, and retaining groove bottom is flushed with cable duct bottom；
(4) electricity consumption welder I-steel prepares two steel I-beams, two steel I-beams is lifted by crane with loop wheel machine, along cable box culvert
It is longitudinally placed in four grooves that foundation pit side-wall has excavated, so that the both ends of steel I-beam is close to cable box culvert side and be parallel to
The setting of cable box culvert, and be fixed with I-steel fixing clamp, so that steel I-beam is kept vertical；
(5) steel I-beam intensity is checked
The intensity of steel I-beam meets formula:
[σ]2>σ2max
Wherein: [σ]2For the allowable stress of steel I-beam, according to table in " Code for design of steel structures " (GB 50017-2014)
3.4.1-1 obtaining；σ2maxFor the maximum deflection direct stress that the steel I-beam after welding is subject to, σ2maxIt is determined by following formula:
In formula: M2maxFor the maximal bending moment on the steel I-beam after welding, y2It is one of the steel I-beam height after welding
Half, Iz1It is the steel I-beam section after welding to its neutral equatorial moment of inertia；
For σ2max<[σ]2, indicate that design is met the requirements；For σ2max>[σ]2, indicate that design is unsatisfactory for requiring, then replace
Steel I-beam specification, and redesign；
4th step is manually drawn except box culvert lower recess soil, and applies I-steel connecting rod；Include:
(1) soil body shape is uniformly dug out using hand excavation's mode along cable box culvert longitudinal direction in the soil body of cable box culvert bottom
At groove, the bottom portion of groove before excavating in design pulls on horizontal line retaining groove bottom in same level；
(2) I-steel connecting rod is placed respectively in each groove on two steel I-beams, and electricity consumption welder I-shaped
Steel connecting rod and two steel I-beams, to form two complete i-beam frames, when welding, keeps I-steel connecting rod and two I-shapeds
Girder steel is vertical；
(3) intensity of I-steel connecting rod is checked
The intensity of I-steel connecting rod meets formula:
[σ]3>σ3max
Wherein: [σ]3For the allowable stress of I-steel connecting rod, according in " Code for design of steel structures " (GB 50017-2014)
Table 3.4.1-1 is obtained；σ3maxFor the maximum deflection direct stress of I-steel connecting rod, σ3maxIt is determined by following formula:
In formula: M3maxFor the maximal bending moment on I-steel connecting rod, y3For the half of I-steel connecting rod height；Iz2For I-steel
Connecting rod section is determined the moment of inertia of its neutral axis by specification hot-rolled steel section (GB/T 706-2008)；
For σ3max<[σ]3, indicate that design is met the requirements, for σ3max>[σ]3, indicate that design is unsatisfactory for requiring, then replace
I-steel connecting rod specification, and redesign；
5th step uses three square steel welding triangle square steel framves at the both ends of each I-steel connecting rod respectively:
(1) first square steel electricity consumption welder on the edge of a wing of I-steel connecting rod, and reserve apart from cable box culvert 2~
The position of 3cm；
(2) second square steel are welded in first square steel close to one end of cable box culvert vertically, and with cable box culvert distance
Remain 2~3cm；
(3) the both ends electric welding machine of third root square steel is welded in the one end and second of first square steel far from box culvert respectively
The upper end of root square steel forms a triangle with preceding two square steel；
6th step, lifting i-beam frame simultaneously anchor；Include:
(1) I-steel fixing clamp is shed, is lifted i-beam frame and cable box culvert bottom gentle touchdown with loop wheel machine, and make I-shaped
The triangle steelframe of steel connecting rod two end is 2~3cm at a distance from cable box culvert, then four ends and its institute to i-beam frame
Gap between the bottom portion of groove soil body is filled with steel building block；
(2) four grooves where four ends of i-beam frame are set up with the template of long 100cm wide 50cm high 100cm, and
Casting concrete anchoring；
(3) casting concrete intensity is checked
The casting concrete meets formula in intensity:
[fc] > p
In formula: [fc] it is concrete crushing strength；P is the practical pressure by steel I-beam of concrete, and p is true by following formula
It is fixed:
In formula: G is cable box culvert weight；A is floor space of the steel I-beam in concrete；
For p < [fc], indicate that design is met the requirements；For p > [fc], indicate that design is unsatisfactory for requiring, then replacement pours mixed
Solidifying soil species class, and redesign；
7th step, after concrete hardening, manually draw except the soil body between the groove for placing I-steel connecting rod, and in cable box culvert
Lower section and I-steel connecting rod between welded reinforcement mesh sheet, and gunite concrete anchor.
Preferably, in the first step, the related data is the design drawing of cable box culvert, comprising: cable box culvert cross section
Figure and the long L of size, that is, cable box culvert, width b, high h, type, the density p of cable slab culvert concretec, thickness d and allowable tensile stress
[σ], cable box culvert inner cable line density ρlAnd length L1。
Preferably, in (1) of the first step, the cable box culvert weight G is determined by following formula:
G=ρcg×2[Lbh+(h-2d)d(L+b)]+ρlg×L1
In formula: ρcFor cable box culvert concrete density, L is cable box culvert length, and b is cable box culvert width, and h is cable box
Contain height, d is cable box culvert concrete thickness, and g is local gravitational acceleration, ρlFor cable box culvert inner cable line density, L1For electricity
Cable box culvert inner cable length.
Preferably, in (2) of the first step:
Maximal bending moment M when the cable box culvert suspends in midair naturallymaxIt is determined by following formula:
The moment of inertia I when the cable box culvert suspends in midair naturally is determined by following formula:
Preferably, in (1) of third step, the excavation cable box culvert soil at both sides slope gradient control is 1:1, excavation
Depth is cable box culvert bottom or less 74cm.
Preferably, in (2) of third step, the width control of the cable duct is 200cm, and the excavation length of cable duct is base
The width in hole.
Preferably, in (3) of third step, the size of four grooves is equal are as follows: height 100cm, width 50cm, depth
100cm。
Preferably, in (4) of third step, each steel I-beam is the common I-shaped of Q235 of I20b by two specifications
The common I-steel of Q235 that steel and two specifications are I18 is welded, and two I18 I-steel are in intermediate, two I20b when welding
I-steel is respectively welded in the upper and lower ends of an I18 I-steel, and guarantees two I20b I-steel and two I18 I-steel
Web is in welding in same perpendicular；
The length of two I20b I-steel and two I18 I-steel be cable box culvert cross over foundation pit width+
200cm。
Preferably, in (5) of third step:
The M2maxIt is determined by following formula:
WhereinTherefore,
The Iz1It is determined by following formula:
In formula: I18It is I18 I-steel section to the moment of inertia of its neutral axis, I20bIt is I20b I-steel section to its neutrality
The moment of inertia of axis, I18And I20bIt is determined by specification hot-rolled steel section (GB/T 706-2008)；h18For the height of I18 I-steel, h20For
The height of I20b I-steel, A18For the area of I18 I-steel, A20For the area of I20b I-steel.
Preferably, in (1) of the 4th step, each groove interval holding is 100cm, the specification of groove be 20cm ×
The number of 20cm, groove are identical as the number of I-steel connecting rod.
Preferably, in (2) of the 4th step, the I-steel connecting rod is the Q235 I-steel of specification I10, I-steel connecting rod
Length is the distance between two steel I-beams.
Preferably, in (3) of the 4th step, the M3maxIt is determined by following formula:
In formula:G is cable box culvert weight, and n is the number of I-steel connecting rod；L3For the length of I-steel connecting rod；
Therefore:
Preferably, in the 4th step (3), the Iz2For I-steel connecting rod I10 Q235 I-steel section to its neutral axis
The moment of inertia is determined by specification hot-rolled steel section (GB/T 706-2008).
Preferably, in the 5th step, the square steel is the square steel of side length 5cm.
Preferably, in (1) of the 5th step, the length of first square steel is I-steel link end to cable box culvert side
The distance of the upper position 2~3cm.
It is highly preferred that the length of second square steel is 2/3rds of cable box culvert height in (2) of the 5th step.
It is highly preferred that the length of the third root square steel is first square steel far from cable box culvert in (3) of the 5th step
Distance of the end to second square steel upper end.
Preferably, in (2) of the 6th step, the concrete is C30 slightly expanded concrete.
Preferably, in (3) of the 6th step, the A is determined by following formula:
A=l1×d1
In formula: l1The length in the concrete of both ends, d are embedded in for steel I-beam1It is wide for the leg of steel I-beam.
Preferably, in the 7th step, the reinforced mesh is 12@150mm steel meshes.
Preferably, in the 7th step, the concrete is C25 early strength concrete.
The present invention compared with prior art, has the following beneficial effects:
The method of the invention efficiently solves the problems, such as to be embedded with underground high voltage cable box culvert on constructing tunnel channel,
The safety that more effectively ensure that cable box culvert with the support of I-steel, avoids the relocating work of high-tension cable box culvert, is whole
A work progress has saved the duration, improves construction efficiency, saves removal charge, reduces construction cost, and alleviates pair
The influence of surrounding resident.
Detailed description of the invention
High-tension cable box culvert construction method embodiment under cast-in-place steelframe protecting field is made referring to the following drawings by reading
Detailed description, other features, purposes and advantages of the invention will become more apparent:
Fig. 1 is that the cable box culvert of one embodiment of the present invention protects plan view；
Fig. 2 is that the cable box culvert of one embodiment of the present invention protects sectional view；
Fig. 3 is that the cable box culvert of one embodiment of the present invention protects side view；
In figure:
1 is steel I-beam, and 1-1 is I20b I-steel, and 1-2 is I18 I-steel；2 be I10 I-steel connecting rod；3 be triangle
Square steel frame, 3-1 are horizontal square steel, and 3-2 is vertical square steel, and 3-3 is bevel edge square steel；4 be steel mesh；5 be cable box culvert；6 be base
Pit enclosure stake；7 be excavation slope line of demarcation, and 8 be the groove for placing I-steel connecting rod, and 9 be the recessed of filling C30 slightly expanded concrete
Slot.
Specific embodiment
The present invention is described in detail combined with specific embodiments below.Following embodiment will be helpful to the technology of this field
Personnel further understand the present invention, but the invention is not limited in any way.It should be pointed out that the ordinary skill of this field
For personnel, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to the present invention
Protection scope.
By taking the light railways of Chongqing as an example, involved cable box culvert is 110KV high-tension cable box culvert, and cable box culvert is cut
Face is 21m across foundation pit length having a size of 1.7m (width) × 1.5m (height), cable box culvert；It is entered and left on construction channel positioned at tunnel,
It is imbedded in the underground depths about 1m.The fender post diameter for channel both sides arrangement of constructing is 70cm, spacing 210cm, and is located at cable
Box culvert two sides.
It is a kind of that base is crossed over using the protection of cast-in-place concrete bracket to prevent the excavation in construction channel from causing cable box culvert hanging
Plan view, sectional view, the side view of the design and construction method of the underground high voltage cable box culvert in hole distinguish as shown in Figure 1, Figure 2, Fig. 3 institute
Show；The method specifically includes the following steps:
The first step collects cable box culvert related data, determines cable box culvert globality
The cable box culvert related data is the size of cable box culvert: long L is 21m, width b is 1.7m, high h is 1.5m；
Cable slab culvert concrete is C30 concrete, antiseepage grade S6, density pcIt is 2.38 × 103kg/m3, according to " concrete structure
Design specification " (GB 50010-2010) cable slab culvert concrete allowable tensile stress [σ] be 1.43N/mm2, thickness d 0.3m；
Cable density p in cable box culvertlIt is 21m for 32.5kg/m, length L；Local gravitational acceleration g takes 9.8N/kg.
(1) according to cable box culvert related data, cable box culvert weight G is determined are as follows:
G=ρcg×2[Lbh+(h-2d)d(L+b)]+ρlg×L1
=2.38 × 103×9.8×2×[21×0.3×1.5+(1.5-2×0.3)×0.3×(21+1.7)]+32.5
×9.8×21
=733417.69N
(2) the maximal bending moment M of pendant cables box culvert is determinedmaxIt is respectively as follows: with the moment of inertia I
(3) the maximum (normal) stress σ when suspention of cable box culvert is determinedmax, and the allowable tensile stress [σ] of the concrete is compared, with
Check the globality intensity of cable box culvert:
[σ]=1.43MPa < σmax=10.83MPa must shift to an earlier date supporting if pendant cables box culvert will necessarily be destroyed.
Second step, surveying setting-out determine cable box culvert and foundation pit enclosure stake position
(1) according to design drawing, cable box culvert 5 and 6 profile point coordinate of foundation pit enclosure stake are calculated, selects TCR402 total station
Coordinate setting-out is carried out to above-mentioned profile point, and is passed through by two people review；
(2) in setting-out, 5 labels are respectively carried out on the two sides contour line of cable box culvert 5, and are pulled on carefully between label
Line is marked in four foundation pit enclosure stakes, 6 hearts, and lime is used to be sprinkling upon filament and foundation pit enclosure stake 6 in the heart as mark.
Third step excavates cable box culvert soil at both sides, presets steel I-beam
(1) using filament to away from being indicated and being spilt lime at 5 two sides 50cm of cable box culvert, with P315C excavator away from electricity
Start to be excavated to far from 5 direction of cable box culvert at the 50cm of cable box culvert 5, the control of excavation slope ratio of slope is 1:1, cutting depth
For 100cm, excavation width 150cm below 5 bottom of cable box culvert；To 5 two sides of cable box culvert close to the residue soil of cable box culvert 5
Body is excavated by the way of hand excavation, forms cable duct；
(2) manual type is used, four sides of the foundation pit enclosure stake 6 far from cable box culvert 5 on construction channel foundation pit side,
One is excavated respectively using cable duct ground the bottom of as, long 100cm, wide 50cm, high 100cm groove 9 (groove is for filling C30
Slightly expanded concrete)；
(3) the I18 I-steel of the I20b I-steel 1-1 tetra- of the steel Q235 of 23m long, the steel Q235 of 23m long are prepared
1-2 two, it will be welded to connect between an I20b I-steel 1-1 with an I18 I-steel 1-2 respectively, obtain two root beads and connect
Steel I-beam 1；
(4) above-mentioned two be welded piece steel I-beam 1 is set up in 5 two sides cable duct of cable box culvert respectively using loop wheel machine
It is 10cm with groove part, apart from cable box culvert 5,100cm in groove is inserted at the both ends of every steel I-beam 1, and makes two
Steel I-beam 1 is longitudinal parallel with cable box culvert 5；Two steel I-beams 1 are fixed with I-steel fixing clamp again, and use I-shaped
Steel fixing clamp keeps two steel I-beams 1 vertical；
(5) steel I-beam intensity is checked
Selected steel I-beam 1 meets following formula in intensity:
[σ]2>σ2max,
In formula: [σ]2For the allowable stress of steel I-beam, determined by the material and thickness of I-steel, according to " steel construction
Design specification " (GB 50017-2014) table 3.4.1-1, [σ]2Take 205MPa；σ2maxMeet following formula:
In formula:
y2For welding after steel I-beam height half, by I20b I-steel and I18 I-steel welding after I-steel
Y in beam2=38cm；
M2maxBy following formula
It is determined as 320870.24Nm；
Iz1It is determined by following formula:
Therefore:
[σ]2=205MPa > σ3max=161.85MPa, meets design requirement.
4th step is manually drawn except the lower recess soil body, and applies connecting rod
(1) manual type is used, is drawn under cable box culvert 5 except soil body grooving, forming groove 8, (groove is for placing
I-steel connecting rod), specification is 20cm × 20cm, and the spacing of each groove 8 is 100cm, and the number n for writing down groove 8 is 18；
(2) it is put into the I10 I-steel connecting rod 2 that steel are Q235 in each groove 8 and is used as connecting rod, I10 I-steel connecting rod 2
Length be 410cm；
(3) I10 I-steel connecting rod 2 and two steel I-beams 1 are welded again, I10 I-steel connecting rod 2 and two when keeping welding
Steel I-beam 1 is vertical, forms a complete i-beam frame；
(4) I-steel connecting rod strength is checked
Selected I10 I-steel connecting rod 2, which is answered, meets formula in intensity:
[σ]3>σ3max
In formula, [σ]3For the allowable stress of I-steel connecting rod, according to " Code for design of steel structures " (GB 50017-2014),
[σ]3Take 205MPa；σ3maxMeet following formula:
In formula: y3For the half of I-steel connecting rod height, y in I10 I-steel3=5cm；Iz2For I-steel connecting rod section pair
The moment of inertia of its neutral axis, I in I10 I-steelz2=245cm4；M3maxBy following formula:
It is determined as 6790.9Nm；
Therefore:
[σ]3=205MPa > σ3max=138.59MPa, meets design requirement.
Triangle steelframe respectively is respectively welded with three square steel at the both ends of each I-steel connecting rod in 5th step；It is specific:
(1) square steel that three side lengths are 5cm, the vertical side of horizontal square steel 3-1,100cm of respectively length 98cm are prepared
The bevel edge square steel 3-3 of steel 3-2,155cm；
(2) the horizontal square steel 3-1 of long 98cm is welded on 2 one end of I10 I-steel connecting rod, and keeps itself and cable box culvert 5
Distance be 2cm；The vertical square steel 3-2 of long 100cm is welded vertically again in horizontal square steel 3-1 close to 5 side end of cable box culvert,
And keeping vertical square steel 3-2 is 2cm at a distance from cable box culvert 5；The bevel edge square steel 3-3 and horizontal square steel 3- of 140cm are welded again
1, vertical square steel 3-2 forms triangle square steel frame 3, when welding the both ends of bevel edge square steel 3-3 be respectively welded in horizontal square steel 3-1 and
The end of vertical square steel 3-2.
6th step, lifting i-beam frame simultaneously anchor
(1) I-steel fixing clamp is unloaded, i-beam frame is promoted using loop wheel machine, keeps I10 I-steel connecting rod 2 rigid with cable duct bottom
Good contact, and make the triangle square steel frame 3 at 2 both ends of I10 I-steel connecting rod and 5 distance of cable box culvert be 2cm, then to I-steel
It is filled with steel building block in gap between four ends of frame 1 and its 9 bottom soil body of groove；
(2) template that long 100cm, width 50cm, high 100cm are set up in construction channel foundation pit side upper groove 9, to I-steel
Four ends of frame 1 pour C30 slightly expanded concrete and are anchored；
(3) selected concrete strength is checked；
The C30 slightly expanded concrete should meet formula in intensity:
[fc] > p,
In formula: [fc] it is C30 slightly expanded concrete compression strength, [fc]=14.3MPa；P is that C30 slightly expanded concrete is real
Pressure of the border by steel I-beam, the p are determined by following formula:
In formula: G is the self weight of cable box culvert 5；A is floor space of the steel I-beam 1 in C30 slightly expanded concrete, and A is by following formula
It determines:
A=l1×d1=100 × 10.2=1020cm2,
In formula: l1The length in both ends C30 slightly expanded concrete, l are embedded in for steel I-beam 11=100cm；d1For I-steel
The leg of beam 1 is wide, d1=10.2cm；
Therefore:
Therefore: p=1.79MPa < [fc]=14.3MPa, meets design requirement.
7th step, after concrete hardening, using manual type, draw except the soil body between cable box culvert lower grooves 8, and
The steel mesh 4 of 12 150mm is welded between I10 I-steel connecting rod 2 below cable box culvert, and sprays C25 early strength concrete and carries out anchor
Gu.
The method of the invention efficiently solves the problems, such as to be embedded with underground high voltage cable box culvert on constructing tunnel channel,
The safety that more effectively ensure that cable box culvert with the support of I-steel, avoids the relocating work of high-tension cable box culvert, is whole
A work progress has saved the duration, improves construction efficiency, saves removal charge, reduces construction cost, and alleviates pair
The influence of surrounding resident.
Specific embodiments of the present invention are described above.It is to be appreciated that the invention is not limited to above-mentioned
Particular implementation, those skilled in the art can make various deformations or amendments within the scope of the claims, this not shadow
Ring substantive content of the invention.
Claims (10)
1. a kind of design and construction method of underground high voltage cable box culvert of protection across foundation pit, which is characterized in that including following step
It is rapid:
The first step collects cable box culvert data, determines cable box culvert globality；Include:
(1) according to the data of cable box culvert, cable box culvert weight G is determined；
(2) according to cable box culvert weight G, size and cable box culvert concrete strength, if determination does not apply safeguard measure, cable
Maximal bending moment M when box culvert suspends in midair naturallymaxWith the moment of inertia I；
(3) the maximum (normal) stress σ when suspention of cable box culvert is determinedmax, and the allowable tensile stress [σ] of cable slab culvert concrete is compared,
Check the globality intensity of cable box culvert；The σmaxIt is determined by following formula:
Wherein: ρcFor cable box culvert concrete density, L is cable box culvert length, and b is cable box culvert width, and h is that cable box culvert is high
Degree, d are cable box culvert concrete thickness, and g is local gravitational acceleration, ρlFor cable box culvert inner cable line density, L1For cable box
Contain inner cable line length；
For [σ] < σmaxIf expression does not apply safeguard measure, suspends cable box culvert naturally in midair, cable box culvert can be destroyed, electricity
The globality of cable box culvert is bad, needs to carry out supporting in advance；
Second step, surveying and locating determine cable box culvert and fender post position；
Using total station according to construction drawing, determines cable box culvert and be located at foundation pit both sides, cable box culvert two sides and near electricity
Four fender post positions of cable box culvert, selection indicates that 8~12 points of contour line mark on the profile of cable box culvert,
Filament is pulled between label, and is marked in fender post center, pulls on filament between adjacent two fender post, and along thin
Line is sprinkled with lime on ground；
Third step excavates cable box culvert soil at both sides, presets steel I-beam；Include:
(1) with the cable box culvert soil at both sides in excavator excavation pit apart from box culvert 50cm or more；
(2) the remaining whole soil bodys in excavation pit inner cable box culvert two sides, form cable duct；
(3) four grooves are excavated in foundation pit side-wall, four grooves is made to be located on foundation pit side four fender posts far from box culvert one
Side and closely fender post, and retaining groove bottom is flushed with cable duct bottom；
(4) welding H-bar prepares two steel I-beams, lifts by crane two steel I-beams with loop wheel machine, is longitudinally placed at base along cable box culvert
In four grooves having excavated of hole side wall, make the both ends of steel I-beam be close to cable box culvert side and be parallel to cable box culvert to set
It sets, and is fixed with I-steel fixing clamp, steel I-beam is made to keep vertical；
(5) steel I-beam intensity is checked
The intensity of steel I-beam meets formula:
[σ]2>σ2max
Wherein: [σ]2For the allowable stress of steel I-beam, σ2maxFor the maximum deflection direct stress that is subject to of steel I-beam after welding,
σ2maxIt is determined by following formula:
In formula: M2maxFor the maximal bending moment on the steel I-beam after welding, y2For the half of the steel I-beam height after welding, Iz1
It is the steel I-beam section after welding to its neutral equatorial moment of inertia；
For σ2max<[σ]2, indicate that design is met the requirements；For σ2max>[σ]2, indicate that design is unsatisfactory for requiring, then replace I-shaped
Girder steel specification, and redesign；
4th step is manually drawn except box culvert lower recess soil, and applies I-steel connecting rod；Include:
(1) in the soil body of cable box culvert bottom along cable box culvert it is longitudinal uniformly using hand excavation's mode dig out the soil body formed it is recessed
Slot, the bottom portion of groove before excavating in design pull on horizontal line retaining groove bottom in same level；
(2) I-steel connecting rod is placed respectively in each groove on two steel I-beams, and electricity consumption welder I-steel connects
Bar and two steel I-beams, to form two complete i-beam frames, when welding, keeps I-steel connecting rod and two steel I-beams
Vertically；
(3) intensity of I-steel connecting rod is checked
The intensity of I-steel connecting rod meets formula:
[σ]3>σ3max
Wherein: [σ]3For the allowable stress of I-steel connecting rod, σ3maxFor the maximum deflection direct stress of I-steel connecting rod, σ3maxUnder
Formula determines:
In formula: M3maxFor the maximal bending moment on I-steel connecting rod, y3For the half of I-steel connecting rod height；Iz2For I-steel connecting rod
The moment of inertia of the section to its neutral axis；
For σ3max<[σ]3, indicate that design is met the requirements, for σ3max>[σ]3, indicate that design is unsatisfactory for requiring, then replace I-shaped
Steel connecting rod specification, and redesign；
5th step uses three square steel welding triangle square steel framves at the both ends of each I-steel connecting rod respectively:
(1) first square steel electricity consumption welder is reserved apart from 2~3cm of cable box culvert on the edge of a wing of I-steel connecting rod
Position；
(2) second square steel are welded in first square steel close to one end of cable box culvert vertically, and keep with cable box culvert distance
For 2~3cm；
(3) one end and second square steel in first square steel far from box culvert are respectively welded with electric welding machine for the both ends of third root square steel
Upper end, with preceding two square steel form a triangle；
6th step, lifting i-beam frame simultaneously anchor, comprising:
(1) I-steel fixing clamp is shed, is lifted i-beam frame and cable box culvert bottom gentle touchdown with loop wheel machine, and connect I-steel
The triangle steelframe at bar both ends is 2~3cm at a distance from cable box culvert, then recessed to four ends of i-beam frame and its place
Gap between the trench bottom soil body is filled with steel building block；
(2) to four grooves where four ends of i-beam frame set up with the matched template of the groove size, and pour mixed
Solidifying soil anchoring；
(3) casting concrete intensity is checked
The casting concrete meets formula in intensity:
[fc] > p
In formula: [fc] it is concrete crushing strength；P is the practical pressure by steel I-beam of concrete, and p is determined by following formula:
In formula: G is cable box culvert weight；A is floor space of the steel I-beam in concrete；
For p < [fc], indicate that design is met the requirements；For p > [fc], it indicates that design is unsatisfactory for requiring, then replaces casting concrete
Type, and redesign；
7th step, after concrete hardening, manually draw except the soil body between the groove for placing I-steel connecting rod, and under cable box culvert
Welded reinforcement mesh sheet between side and I-steel connecting rod, and gunite concrete anchors.
2. a kind of design and construction method of underground high voltage cable box culvert of the protection according to claim 1 across foundation pit,
It is characterized in that, in the first step, the data is the design drawing of cable box culvert, comprising: cable box culvert cross-sectional view and size are
Long L, the width b, high h of cable box culvert, type, the density p of cable slab culvert concretec, thickness d and allowable tensile stress [σ], cable box
Contain inner cable line density ρlAnd length L1。
3. a kind of design and construction method of underground high voltage cable box culvert of the protection according to claim 1 across foundation pit,
It is characterized in that there is one or more of feature:
In (1) of the first step, the cable box culvert weight G is determined by following formula:
G=ρcg×2[Lbh+(h-2d)d(L+b)]+ρlg×L1
In formula: ρcFor cable box culvert concrete density, L is cable box culvert length, and b is cable box culvert width, and h is that cable box culvert is high
Degree, d are cable box culvert concrete thickness, and g is local gravitational acceleration, ρlFor cable box culvert inner cable line density, L1For cable box
Contain inner cable line length；
In (2) of the first step:
Maximal bending moment M when the cable box culvert suspends in midair naturallymaxIt is determined by following formula:
The moment of inertia I when the cable box culvert suspends in midair naturally is determined by following formula:
4. a kind of design and construction method of underground high voltage cable box culvert of the protection according to claim 1 across foundation pit,
It is characterized in that there is one or more of feature:
In (1) of third step, the excavation cable box culvert soil at both sides slope gradient control is 1:1, and the depth of excavation is cable
74cm below box culvert bottom；
In (2) of third step, the width control of the cable duct is 200cm, and the excavation length of cable duct is the width of foundation pit；
In (3) of third step, the size of four grooves is equal are as follows: height 100cm, width 50cm, depth 100cm；
In (4) of third step, each steel I-beam is by the common I-steel of Q235 that two specifications are I20b and two rule
Lattice are that the common I-steel of Q235 of I18 is welded, and two I18 I-steel are in intermediate, two I20b I-steel difference when welding
The upper and lower ends of an I18 I-steel are welded in, and guarantee that the web of two I20b I-steel and two I18 I-steel is welding
When in same perpendicular；The length of two I20b I-steel and two I18 I-steel is the base that cable box culvert is crossed over
Cheat width+200cm.
5. a kind of design and construction method of underground high voltage cable box culvert of the protection according to claim 1 across foundation pit,
It is characterized in that, in (5) of third step:
The M2maxIt is determined by following formula:
WhereinTherefore,
The Iz1It is determined by following formula:
In formula: I18It is I18 I-steel section to the moment of inertia of its neutral axis, I20bIt is I20b I-steel section to its neutral axis
The moment of inertia；h18For the height of I18 I-steel, h20For the height of I20b I-steel, A18For the area of I18 I-steel, A20For I20b
The area of I-steel.
6. a kind of design and construction of underground high voltage cable box culvert of the protection according to claim 1-5 across foundation pit
Method, which is characterized in that there is one or more of feature:
In (1) of-the four step, each groove interval holding is 100cm, and the specification of the groove is 20cm × 20cm, recessed
The number of slot is identical as the number of I-steel connecting rod；
In (2) of-the four step, the I-steel connecting rod is the Q235 I-steel of specification I10, and the length of I-steel connecting rod is two
Distance between steel I-beam.
7. a kind of design and construction of underground high voltage cable box culvert of the protection according to claim 1-5 across foundation pit
Method, which is characterized in that in (3) of the 4th step, the M3maxIt is determined by following formula:
In formula:G is cable box culvert weight, and n is the number of I-steel connecting rod；L3For the length of I-steel connecting rod；
Therefore:
8. a kind of design and construction of underground high voltage cable box culvert of the protection according to claim 1-5 across foundation pit
Method, which is characterized in that there is one or more of feature:
In-the five step, the square steel is the square steel of side length 5cm；
In (1) of-the five step, the length of first square steel is 2~3cm on I-steel link end to cable box culvert side
The distance set；
In (2) of-the five step, the length of second square steel is 2/3rds of cable box culvert height；
In (3) of-the five step, the length of the third root square steel is first end of the square steel far from cable box culvert to second
The distance of square steel upper end.
9. a kind of design and construction of underground high voltage cable box culvert of the protection according to claim 1-5 across foundation pit
Method, which is characterized in that there is one or more of feature:
In (2) of-the six step, the concrete is C30 slightly expanded concrete；
In (3) of-the six step, the A is determined by following formula:
A=l1×d1
In formula: l1The length in the concrete of both ends, d are embedded in for steel I-beam1It is wide for the leg of steel I-beam.
10. a kind of design of underground high voltage cable box culvert of the protection according to claim 1-5 across foundation pit is applied
Work method, which is characterized in that there is one or more of feature:
In-the seven step, the reinforced mesh is 12@150mm steel meshes；
In-the seven step, the concrete is C25 early strength concrete.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009060710A (en) * | 2007-08-31 | 2009-03-19 | Chubu Electric Power Co Inc | Relocation construction method for underwater cable |
| CN104518473A (en) * | 2014-12-31 | 2015-04-15 | 上海市机械施工集团有限公司 | Suspension protection structure and method of cable box culvert pipeline |
| CN104676110A (en) * | 2015-01-22 | 2015-06-03 | 中国地质大学（武汉） | On-site overhanging protection method of high-voltage cable bailey truss under condition of excavation of foundation pit |
| CN105972313A (en) * | 2016-05-30 | 2016-09-28 | 广州地铁设计研究院有限公司 | Overhang method and overhang structure for engineering pipeline stretching across foundation pit |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009060710A (en) * | 2007-08-31 | 2009-03-19 | Chubu Electric Power Co Inc | Relocation construction method for underwater cable |
| CN104518473A (en) * | 2014-12-31 | 2015-04-15 | 上海市机械施工集团有限公司 | Suspension protection structure and method of cable box culvert pipeline |
| CN104676110A (en) * | 2015-01-22 | 2015-06-03 | 中国地质大学（武汉） | On-site overhanging protection method of high-voltage cable bailey truss under condition of excavation of foundation pit |
| CN105972313A (en) * | 2016-05-30 | 2016-09-28 | 广州地铁设计研究院有限公司 | Overhang method and overhang structure for engineering pipeline stretching across foundation pit |
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