CN114525808A - Construction method for ground beam of edge portal crane of deep foundation pit - Google Patents

Abstract

A method for constructing a ground beam of a gantry crane at the edge of a deep foundation pit comprises the following steps of carrying out grading backfill treatment on a gap space near an inclined wall of a retaining wall before construction of the ground beam of the gantry crane, pouring the ground beam of the gantry crane on a filling body, setting a main rib protective layer and a temperature gap, arranging an embedded part on the ground beam of the gantry crane, installing a travelling track of the gantry crane on the ground beam of the gantry crane under the cooperation of the embedded part, and enabling the ground beam of the gantry crane to be far away from the deep foundation pit compared with the retaining wall in the direction horizontal to the ground.

Description

Construction method for ground beam of edge portal crane of deep foundation pit

Technical Field

The invention relates to the field of construction hoisting device erection, in particular to a construction method of a ground beam of a gantry crane at the edge of a deep foundation pit.

Background

In large-scale road engineering, when a road foundation is built, the work of excavating a deep foundation pit is generally required according to requirements, and the deep foundation pit engineering is generally an earthwork excavation and supporting engineering of a foundation pit (groove) with excavation depth exceeding 5m or excavation depth not exceeding 5m but with complicated geological conditions, surrounding environment and underground pipelines or influencing the safety of adjacent buildings (structures) according to regulations. For the deep foundation pit constructed by the open cut method, in some construction occasions, based on some construction requirements, a certain amount of hoisting equipment needs to be arranged on each section of the deep foundation pit to transport the steel support frame and the main structure construction material in the foundation pit, and for the heavy and long construction material and the steel support frame, a portal crane with relative carrying capacity and good use effect becomes a good choice. The general structure of the portal crane is similar to the shape of a door, and the portal crane at least comprises one main beam and two supporting legs, wherein the two supporting legs are respectively supported at two ends of the main beam in the length direction so that the whole crane presents an inverted U-shaped door-shaped or door frame-shaped structure, and in some portal crane models, overhanging cantilever beams can be additionally arranged at two ends of the main beam.

At present most gantry crane is for both sides hat roof beam and gantry crane basis integrated design that the basic design form that adopts on the erection of deep basal pit both sides because can reduce gantry crane's span and practice thrift like this and take up an area of the space. However, the arrangement scheme has great potential safety hazards in the construction process, for example, serious foundation pit safety accidents are caused by derailment of the gantry crane, and meanwhile, the construction height of the crown beam is increased, and the construction cost is increased.

Furthermore, there are differences in one aspect due to the understanding of those skilled in the art; on the other hand, since the applicant has studied a great deal of literature and patents when making the present invention, but the disclosure is not limited thereto and the details and contents thereof are not listed in detail, it is by no means the present invention has these prior art features, but the present invention has all the features of the prior art, and the applicant reserves the right to increase the related prior art in the background.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a construction method of a ground beam of a gantry crane at the edge of a deep foundation pit, which comprises the following steps of carrying out grading backfill treatment on a gap space near an inclined wall of a retaining wall before the construction of the ground beam of the gantry crane, pouring the ground beam of the gantry crane on a filling body, arranging a main rib protective layer and a temperature gap, arranging an embedded part on the ground beam of the gantry crane, installing a travelling track of the gantry crane on the ground beam of the gantry crane under the matching of the embedded part, and enabling the ground beam of the gantry crane to be far away from the deep foundation pit compared with the retaining wall in the direction horizontal to the ground.

Preferably, the bottom end of the retaining wall is arranged on a crown beam, and the crown beam is constructed by communicating the tops of a plurality of diaphragm walls.

Preferably, the diaphragm wall is arranged in a deep groove formed in soil on the peripheral side of the edge of the deep foundation pit.

Preferably, the width of the bottom of the retaining wall is less than the width of the top of the crown beam, and the retaining wall is arranged at the position of the top of the crown beam close to one side of the deep foundation pit.

Preferably, the other side of the side, far away from the deep foundation pit, of the crown beam is in contact with a guide wall, the guide wall is at least provided with a first guide wall surface and a second guide wall surface which are perpendicular to each other, the first guide wall surface is horizontal to the ground and at least provided with one part arranged below the ground in the existing condition, and the second guide wall surface is perpendicular to the ground and is in contact with the crown beam.

Preferably, the portion of the second guide wall surface beyond the portion contacting the crown beam and the inclined wall of the retaining wall form a clearance space therebetween.

Preferably, the gap space is in a structure that the short upper bottom is contacted with the crown beam, the long lower bottom is far away from the trapezoidal body structure of the crown beam, and the filling body formed by backfilling in the space is in a consistent structure.

Preferably, the lower bottom of the filling body is coplanar with the first guide wall surface and is parallel to the horizontal plane, and a cushion layer is arranged on the lower bottom and the first guide wall surface.

Preferably, the gantry crane ground beam is arranged on the cushion layer, and the sum of the height of the gantry crane ground beam in the vertical direction and the thickness of the cushion layer is equal to the vertical distance from the surface of the existing ground to the surface of the first guide wall.

Preferably, the gantry crane ground beam is arranged on one side close to the existing ground, and a drainage ditch contacted with the side edge of the gantry crane ground beam is arranged on the pad body on the other side of the gantry crane ground beam.

The gantry crane has the advantages that the contact position of the gantry crane is arranged on the outer side of the deep foundation pit, and the retaining wall with the slope is introduced to shield the ground beam of the gantry crane, so that even if the problem of left-right shaking or derailment in the horizontal direction caused by unstable supporting legs of the gantry crane occurs, the gantry crane can be blocked by multiple parts, such as the drainage ditch and the retaining wall, and the great potential safety hazard caused by the overturning of the gantry crane is prevented. And the ground beam of the gantry crane is arranged at the position close to the ground of the deep foundation pit in the current situation, so that the main weight bearing of the gantry crane is concentrated on the ground. The gantry crane track sets up in the retaining wall outside, compares the advantage that sets up to have on the hat roof beam mainly be security, economic nature and material transport's convenience.

(1) Safety: if the gantry crane rail is arranged at the upper part of the crown beam of the foundation pit, if derailing occurs in the walking process, the gantry crane is likely to fall into the foundation pit, personal injury is caused to operators in the foundation pit, and therefore great safety accidents are likely to be caused; if the portal crane track sets up in the retaining wall outside, even take place the derail phenomenon, also can not fall into the foundation ditch because of the effect of retaining wall to avoid great incident to take place.

(2) The economic efficiency is as follows: the arrangement of the foundation pit crown beam needs to consider the section size of the enclosure structure and the supporting stress requirement, meanwhile, the design height of the top surface of the general crown beam is lower than the ground in the prior art, if a gantry crane track is arranged at the upper part of the foundation pit crown beam, the section size of the crown beam is increased, and the cost is higher; the portal crane track is arranged on the outer side of the retaining wall, so long as the structural strength of the foundation beam is calculated through mechanics checking, the bearing capacity requirement of the portal crane track foundation can be met, and the portal crane track has the characteristics of small section size, simplicity in construction operation, low cost, convenience in dismantling and the like.

(3) Material transportation convenience: the gantry crane track is arranged outside the retaining wall, the lifting range of objects at the cantilever end of the gantry crane can be guaranteed to the maximum extent, the gantry crane track is extremely convenient to load and unload some vehicle-mounted transported materials, the material transport vehicle can be directly stopped below the cantilever end of the gantry crane, and the material transport speed is greatly improved.

Drawings

FIG. 1 is a diagram of the protocol steps for a preferred embodiment of the present invention;

FIG. 2 is a schematic overall cross-sectional view of a gantry crane according to a preferred embodiment of the present invention;

in the figure: 001. a ground connecting wall; 002. a crown beam; 003. a filler; 004. a guide wall; 005. a retaining wall; 006. a cushion layer; 007. the ground in the prior art; 008. a gantry crane ground beam; 009. and (7) a drainage ditch.

Detailed Description

This is described in detail below with reference to figures 1 and 2.

In the construction of large roads, for the purpose of building a solid foundation of a road, it is necessary to excavate a deep foundation pit, which is a pit excavation work with an excavation depth of more than 5m or an earth excavation and supporting work of a foundation pit (groove) with an excavation depth of not more than 5m but is affected by complicated geological conditions, surrounding environments and underground pipelines or the safety of adjacent buildings (structures), and the deep foundation pit has a structure similar to a groove or a U-shaped structure, in which the middle portion thereof is recessed below the ground and is generally leveled into a plane, and both sides thereof extend downward along the ground or near the ground and are bordered by the middle portion. The deep basal pit both sides are provided with guan liang 002, and guan liang 002 is the beam structure that foundation ditch slope protection stake top surface set up, and its effect is in order to form a comparatively complete whole with the slope protection stake interconnect that one of them unilateral interval row of following deep basal pit length direction together to the effect that prevents deep basal pit edge collapse of reinforcing slope protection stake. The structure of the slope protection pile is similar to a column structure, also called as a row pile, the slope protection pile is a pile which is arranged along the edge of a foundation pit and is used for preventing a slope from collapsing, the slope protection pile can effectively prevent the foundation displacement, sinking and the like of the adjacent original engineering, and one of the purposes of arranging the crown beams 002 is to connect the slope protection piles which are arranged at intervals together so as to enhance the integral stress resistance of the slope protection piles.

For the purpose of transporting steel support frame and some major structure construction materials in the deep basal pit, in some projects, need set up gantry crane in the deep basal pit top, gantry crane roughly structurally is similar to the shape of door, it comprises a girder and two supporting legs at least, two supporting legs support respectively on the length direction's of girder both ends so that the whole portal shape or the door frame shape structure that presents the shape of falling U-shaped of hoist, in some gantry crane models, can additionally set up overhanging cantilever on the both ends of girder. From top to bottom, gantry crane has two supporting leg structures at least to be the structure of cell type and gantry crane's girder bearing for the cooperation deep basal pit, two supporting legs are generally placed and are close to ground level both sides at the deep basal pit, and in current engineering, often set up gantry crane's two supporting legs respectively on the hat roof beam 002 that the deep basal pit both sides set up. Because the row's stake of constituteing guan liang 002 is just in time to be arranged along the both sides of deep basal pit length trend respectively, consequently guan liang 002 moves towards also just in time to accord with the length trend of deep basal pit, erects the supporting leg on two guanliangs 002 and makes gantry crane's main beam can transversely be arranged in order to the article in the handling deep basal pit above the deep basal pit.

However, the portal crane disposed on the crown beam 002 has a great potential safety hazard in use, because the foundation of the crown beam 002 is some slope protection piles or row piles, the crown beam 002 is built on the foundation of these piles, if the floating slurry at the upper end of the row piles is not or is not effectively removed during the construction of the crown beam 002, the structure of the crown beam 002 is likely to be unstable, particularly after the track used by the portal crane support legs is additionally disposed on the crown beam 002, under the heavy pressure of the portal crane, the crown beam 002 has a great potential safety hazard, for example, the unstable gravity causes shaking, and partial row piles are settled to cause uneven track, which may cause the derailment problem of the portal crane. If the use safety of the crown beam 002 needs to be improved, works such as crown beam reinforcement, lifting, foundation reinforcement and the like need to be performed, but this undoubtedly increases the construction cost.

Therefore, the invention provides a construction method of a ground beam of a portal crane at the edge of a deep foundation pit, which is used for the construction of the supporting engineering of the portal crane arranged at two sides of the deep foundation pit. This scheme gantry crane considers foundation ditch safety, sets up the hoist track in the deep basal pit barricade outside. The scheme has the advantages that the foundation construction is simple, the construction cost is reduced, and the potential safety hazard caused by derailment to the foundation pit can be reduced to the maximum extent.

Specifically, the construction scheme mentioned above will be described in more detail, as shown in fig. 1, this is a schematic structural diagram of a track arrangement position utilized by a gantry crane, that is, a gantry crane, of a support leg of the gantry crane in the present scheme, a part of the gantry crane is not shown in the figure, and the track arrangement position also only shows a half part, it should be noted that the structure shown in the figure is at least symmetrical about a center line of a deep foundation pit, that is, the track arrangement position has at least two symmetrical positions, and the two support legs can be respectively suitable for installation and bearing of the two support legs of the gantry crane. The structure on the road surface side shown in fig. 1, that is, the structure on the side of the road surface not excavated around the deep foundation pit, i.e., as can be seen from the figure, has a portion of the existing ground surface 007, which is located on the left side in the figure, and the portion of the deep foundation pit is the portion on the other side away from the existing ground surface 007, which is located on the right side in the figure, and can be understood by referring to fig. 2. The left and right positional explanations described above are only for the positional relationship shown in the drawings, and actually show only the relative positional relationship between the ground 007 and the deep foundation pit, and are not related to the actual left and right direction.

The continuous wall structure used for bearing and retaining water is arranged on the peripheral sides of two length directions of the deep foundation pit, at least one part of the continuous wall structure is deeply buried in the soil on the peripheral sides, the continuous wall can also be called as an underground continuous wall or an underground continuous wall 001, a long and narrow deep groove which is deep into the soil is excavated on the periphery of an excavation project, namely the peripheral side of the deep foundation pit in the embodiment, under the condition of slurry wall protection, a reinforcement cage is placed in the deep groove, and then the reinforcement cage is poured to form a low concrete wall structure formed by combining strip-shaped concrete.

The continuous wall is formed by casting a structure of a long and narrow reinforcement cage which is formed by long and narrow deep grooves capable of being excavated along the peripheral line of the deep foundation pit, so that the continuous wall is similar to a column-shaped, rod-shaped or strip-shaped structure. Similarly, the top of the plurality of underground diaphragm walls 001 arranged along the length direction of the deep foundation pit may be referred to as a crown beam 002. This embodiment does not do so, but provides the retaining wall 005 on the top of the crown beam 002, compared to providing the track directly on the crown beam 002 in the conventional art. In this embodiment, in the index of excavation of the deep foundation pit, the depth of the deep foundation pit is at least smaller than the sum of the height of the crown beam 002 and the height of the retaining wall 005, and for convenience of description, the pit bottom plane of the upgrade pit may be set as an initial plane, and the distance generated by moving an imaginary point vertically upward from the initial plane away from the initial plane is calculated as a height value accumulated from 0, so that the height of the crown beam 002 may be referred to as a first height, which may be expressed as the distance from the top of the crown beam 002 to the initial plane, which corresponds to a length portion where the continuous wall constituting the crown beam 002 is deeper into the bottom of the deep foundation pit without consideration. The height of the retaining wall 005 may be referred to as a second height, which is a vertical height from the bottom to the top of the structure of the retaining wall 005 itself, and since the retaining wall 005 is directly disposed on the crown beam 002 in a bottom contact manner, the sum of the first height plus the second height may represent a distance from the top of the retaining wall 005 to the initial plane, that is, a total height. The excavation depth of the deep foundation pit may be referred to as a third height from the viewpoint of the initial plane, and the three heights are related in that the sum of the first height and the second height is greater than or equal to the third height. In order to ensure the self strength and functionality of the retaining wall 005 and the crown beam 002, the first height and the second height cannot be set too small or too large, and the height of the retaining wall 005 and/or the crown beam 002 can be designed according to the requirement of the engineering site.

The retaining wall 005 constitutes a trapezoidal face as viewed in cross section, that is, the retaining wall 005 itself constitutes a shape similar to a structure of a slope body or an inclined platform body, and the width of the bottom of the retaining wall 005 connected to the crown beam 002 does not completely match the width of the top of the crown beam 002 but is smaller than the width of the top of the crown beam 002, and the width of the bottom of the retaining wall 005 may be referred to as a first width, and the width of the top of the crown beam 002 as a second width, and the first width is smaller than the second width.

The retaining wall 005 is provided at one side near the deep foundation pit, and the guide wall 004 is provided at the other side far from the retaining wall 005. Before the deep groove grooving of the continuous wall construction, in order to ensure the grooving direction and shield the side wall from the soil, a guide wall 004 is firstly built on the side wall of the deep foundation pit. The guide wall 004 is generally L-shaped and has two planes perpendicular to each other, one of which is substantially parallel to the ground and the other of which is substantially parallel to the side wall of the deep foundation pit, i.e., in a direction perpendicular to the ground, when constructed. In the present embodiment, the above-mentioned plane parallel to the ground plane is provided below the existing ground plane 007, and this plane may be referred to as a first guide wall 004 plane, and accordingly, the other plane of the guide wall 004 may be referred to as a second guide wall 004 plane. The ground connecting wall and the top crown beam 002 are closer to the center line of the deep foundation pit than the second guide wall 004 in the horizontal direction (not shown in the figure).

As described above, the width of the retaining wall 005 is smaller than the width of the top of the crown beam 002, thereby forming a space, which may be referred to as an interstitial space, above the top of the crown beam 002, and the interstitial space is filled with graded backfill tamping so as to form a solid body, which may be referred to as a filling body 003. From the above, this interstitial space, including the obturator 003 that it fills and forms is the structure of falling the trapezoidal body, if stipulate that a longer base is called the lower bottom, and a shorter base is called the upper bottom, then its upper bottom is close to crown rail 002 top position, and the lower base is kept away from crown rail 002 top and is just coplane with first wall 004 face of leading.

As described above, the first guide wall 004 face is constructed under the existing ground surface 007, and thus the vertical distance from the existing ground surface 007 to the first guide wall 004 face may be referred to as a first vertical distance. In the prior art, the ground 007 has a certain horizontal distance with the junction between the first guide wall 004 and the second guide wall 004 in the horizontal direction, that is, the edge of the first guide wall 004 close to one side of the deep foundation pit, and this distance can be referred to as a first horizontal distance. That is, the current-state floor 007 does not completely cover the entire area of the first guide wall 004 face, but only covers a portion.

The lower bottom of the infill 003 and the part of the first guide wall 004 partially exposed out of the coverage area of the existing ground 007 are covered with the cushion layer 006, the size of the cushion layer 006 can be selected according to the actual engineering situation, in the embodiment, the C15 cushion layer 006 with the thickness of 10cm can be selected, and the thickness of the cushion layer 006 can be called as the thickness of the cushion layer 006. At least one portion of the blanket 006 is disposed under the existing ground 007, and particularly, the length of the blanket 006 in a horizontal cross section (as viewed in the drawing) may be referred to as a width of the blanket 006, one end of the width of the blanket 006 starting from the existing ground 007 and extending to an inclined wall of the retaining wall 005 near the deep excavation. The width of the portion of the mat layer 006 pressed downward by the existing ground 007 may be expressed in numerical terms as the width of the mat layer 006 minus the first horizontal distance and the length of the lower bottom of the filling body 003.

The overhead area above the cushion layer 006 is provided with a gantry crane ground beam 008 and a drainage ditch 009. The gantry crane ground beam 008 has a substantially rectangular rail as a whole, and has two edge length values as viewed in the cross section shown in the figure, where the edge length in the horizontal direction may be referred to as a ground beam width value and the edge length in the vertical direction may be referred to as a ground beam height value. Based on different engineering requirements, such as different self weights of the gantry crane, expected bearing weights, etc. In this embodiment, a size scheme of 300mm by 400mm is selected as the ground beam width value.

The drainage ditch 009 is generally of a channel type structure for draining rainwater or other moisture to a construction site, and the width of the drainage ditch 009 in the horizontal direction may be referred to as the width of the drainage ditch 009, so that the sum of the width of the drainage ditch 009 and the width of the floor beam is approximately equal to the sum of the first horizontal distance and the length of the lower bottom of the packing body 003, and "approximately" in the above description is considered in consideration of the inclined wall structure of the retaining wall 005, and the widths of the respective floors in the horizontal plane may be slightly different depending on the inclined wall structure of the retaining wall 005. Here, the positions of the above-described structures at each vertical height may be described in a direction perpendicular to the ground. A part of the diaphragm wall 001 located at the lowest position is deeply buried in a deep groove in the soil; the tops of the plurality of underground connecting walls 001 are communicated to form a crown beam 002; a retaining wall 005 with the bottom width smaller than the top width of the crown beam 002 is constructed on one side of the top of the crown beam 002 close to the deep foundation pit, a guide wall 004 is constructed on one side of the crown beam 002 close to the ground 007 in the current situation, the construction time of the guide wall 004 is earlier than that of the underground connecting wall 001, and the second guide wall 004 of the guide wall 004 vertical to the ground extends upwards to exceed the crown beam 002; the second guide wall 004 surface and the side wall of the retaining wall 005 form a roughly trapezoidal clearance space above the crown beam 002, and the clearance space is filled into a filling body 003 with a roughly consistent shape by utilizing a grading backfill tamping mode; the lower bottom surface of the filling body 003 with longer length is coplanar with the first guide wall 004 surface and is horizontal to the ground; part of the first guide wall 004 is arranged below the existing ground 007 in an embedded manner; a cushion layer 006 is constructed above the first guide wall 004 surface and the lower bottom surface of the filling body 003 which are beyond the range of the existing ground 007; a gantry crane ground beam 008 and a drainage ditch 009 are constructed above the cushion layer 006. The side of the bedding layer 006, the drainage ditch 009 and the infill 003 near the deep foundation pit all contact the inclined wall of the retaining wall 005. The first vertical distance is equal to the sum of the height of the ground beam and the width of the pad layer 006, which is 100mm +400mm in this embodiment, 500 mm.

In one embodiment, the method steps are as follows.

S1, before construction of the gantry crane ground beam 008, graded backfilling is conducted on a gap space near the inclined wall of the retaining wall 005 to form a filling body 003, and graded backfilling is conducted through graded gravel (secondary ash) layered backfilling and then tamping is conducted.

The tamping can be carried out manually or mechanically.

S2, pouring a gantry crane ground beam 008 on the filling body 003, and arranging a main reinforcement protective layer and a temperature gap.

In the embodiment, the ground beam 008 of the gantry crane is cast by C25 concrete, and the thickness of the main reinforcement protective layer is 40 mm. And a temperature seam is arranged every 40m, and the construction length of each section of the ground beam can be set on site according to actual conditions.

In this embodiment, the main reinforcement of the ground beam is divided into 3 layers, the upper layer adopts 3C14, the middle layer adopts 2C12, the lower layer adopts 4C16+2C12, and the stirrups adopt A6.5 and have a distance of 200 mm.

S3, arranging embedded parts on the ground beam 008 of the gantry crane, wherein the embedded parts are steel plates with the thickness of 300 multiplied by 100 multiplied by 20mm, and 2A 10 steel bars with the length of 300mm are anchored in the steel plates. And plug welding is carried out between the steel plate and the steel bar, and the distance between the embedded parts is 900 mm.

The embedded part is used for fixing the I-shaped rail, so that the I-shaped rail cannot generate deflection, horizontal vibration, displacement and the like on the ground beam.

And S4, mounting a gantry crane walking track on the gantry crane ground beam 008 under the cooperation of the embedded parts.

After the ground beam construction is completed, the support legs of the portal crane can be installed on the travelling track of the portal crane.

In the embodiment, the filling body 003 is formed by a filling manner of graded gravel instead of a conventional scheme of concrete pouring, which takes into account the fact that the ground beam 008 of the gantry crane is arranged above the filling body 003, and when the supporting legs of the gantry crane contact the ground beam 008 of the gantry crane, at least half of the weight of the gantry crane is transferred to the filling body 003 on one side. And because the hoisting structure on the gantry crane can move along the direction transversely arranged in the foundation pit, the pressures applied to the ground direction by the supporting legs erected on the two sides of the foundation pit are inconsistent within a certain period of time, and the filling bodies 003 positioned on the two sides of the foundation pit can bear different pressures at different times under different working conditions due to the gravity center shift. Therefore, the problem can be effectively relieved by adopting the graded sandstone layered filling scheme, wherein the sand in the filling components is used for filling substances in gaps among the fine stones, so that the filling body 003 can be formed into a firmer filling body 003 in a mode that microscopic fine gaps are filled by the sand after backfilling and tamping. Furthermore, the stones, i.e. the stones, in the gravel material constitute an initial gravitational stress on the gantry crane or cause the influence of the varying pressure generated by the gantry crane during operation on the filling bodies 003 to be dispersed. Specifically, the conventional means adopts concrete to construct the filler 003, and when the filler 003 is subjected to pressure of a gantry crane, particularly to variable pressure generated when the gantry crane runs or internal stress change caused by hydration heat in the interior when thermal management is poor in the concrete pouring process, cracks are likely to be generated in the concrete or the cracks are increased, so that the filler 003 is easy to crack, and further, a ground beam 008 of the gantry crane arranged on the filler is loosened or collapsed, and serious accidents such as derailment of the gantry crane are caused. And the grit gradation that this scheme adopted is filled, increased the tiny stone that the several mixes and random position in the filler, the stone not only can strengthen the grit gradation mixture's physical strength to possess certain shock-absorbing capacity between stone or the adjacent stone, this is because the stone possesses certain elasticity, can cushion the pressure that above-mentioned portal crane produced or the pressure that changes, can repair or resume the inside deformation of obturator 003 that has produced through the filling effect and the elastic action of stone itself simultaneously.

This scheme sets up the gantry crane track in the retaining wall 005 outside, compares the advantage that sets up to have on guan liang 002 and mainly is security, economic nature and material transport's convenience, and concrete advantage is as follows.

(1) Safety: if the gantry crane rail is arranged at the upper part of the foundation pit crown beam 002, if derailing occurs in the walking process, the gantry crane is likely to fall into the foundation pit, personal injury is caused to operators in the foundation pit, and therefore great safety accidents are likely to be caused; if the gantry crane track is arranged outside the retaining wall 005, even if the derailment phenomenon occurs, the gantry crane track can not fall into a foundation pit due to the action of the retaining wall 005, so that a large safety accident is avoided.

(2) The economic efficiency is as follows: the arrangement of the foundation pit crown beam 002 needs to consider the section size of the enclosure structure and the supporting stress requirement, meanwhile, the design height of the top surface of the general crown beam 002 is lower than the existing ground 007, if a gantry crane track is arranged on the upper part of the foundation pit crown beam 002, the section size of the crown beam 002 is increased, and the cost is higher; the gantry crane track is arranged on the outer side of the retaining wall 005, and the foundation beam structural strength is calculated through mechanics checking to meet the bearing capacity requirement of the gantry crane track foundation, so that the gantry crane track has the characteristics of small section size, simplicity in construction operation, low cost, convenience in dismantling and the like.

(3) Material transportation convenience: the gantry crane track is arranged outside the retaining wall 005, the lifting range of objects at the cantilever end of the gantry crane can be guaranteed to the greatest extent, the gantry crane track is extremely convenient to load and unload materials for vehicle-mounted transportation, a material transport vehicle can be directly stopped below the cantilever end of the gantry crane, and the material transport speed is greatly improved.

This scheme will be used for the ground beam mounted position of the orbital installation of backing portal crane to remove to foundation ditch outside current situation ground 007 position from conventional guan liang 002 top position for the space at guanliang 002 top is released, this scheme borrows this at guanliang 002 top to be provided with can strengthen the backfill structure and the retaining wall 005 structure of the dominant property of guanliang 002 own dominant property and portal crane ground beam 008 simultaneously, except can preventing to lead to the portal crane derail with the conventional scheme of setting up on guanliang 002 of track, and then the portal crane who causes smashes into the foundation ditch and cause the incident problem, still utilize guanliang 002 to be released the space and set up intensity to ground beam and guanliang 002 itself in reverse, environmental safety protection provides the effect complementary.

First, the general top surface of the crown beam 002 is designed to be lower than the existing ground 007, and the existing ground 007 is the ground on which the periphery of the foundation pit is higher than the bottom of the foundation pit in elevation, and is generally the ground with certain compliance strength after being constructed.

In the prior art, the gantry crane track is arranged above the crown beam 002 inside the deep foundation pit, after the gantry crane is installed and put into use, the part at the bottom of the foundation pit can be caused to subside in the process of load operation, and a large construction error can be caused under the condition that no antagonistic construction measures or redundant design is carried out, so that a series of other foundation pit structure problems are caused. Meanwhile, the operation of the gantry crane also causes certain deformation influence on the top beam 002 itself and the foundation pit slope support partially forming the top beam 002 foundation, after the deformation value at a certain position exceeds the designed bearable limit, the top beam 002 or the corresponding support is damaged and irrecoverably deformed due to strong strain force, so that more engineering problems are caused, the engineering has to be suspended or reversed to maintain the supports and the top beam 002, the whole engineering progress is slowed down, and the construction efficiency is seriously reduced. On the other hand, the arrangement of the ground beam 008 of the gantry crane on the inner side of the foundation pit is actually to hook the use foundation of the gantry crane with the structural attributes of the foundation pit, so that the property of the gantry crane is also influenced by the condition of the foundation pit in the state, if the foundation pit has structural changes such as large transverse deformation, longitudinal deformation, settlement and the like in subsequent excavation, repair excavation, adjustment, reconstruction and other projects, the gantry crane can directly bear corresponding deformation strain force, and the gantry crane has the metal stress relaxation or metal fatigue phenomenon that the steel structure is influenced by stress for a long time under the condition that the strain force degree is relatively light, so that the potential safety hazard of the fracture of the steel structure of the gantry crane is formed; under the condition of a relatively medium degree, axial bending of the gantry crane is caused to cause unbalanced lifting points and non-centering, so that the lifting effect is reduced, or support legs of the gantry crane cannot smoothly move on a rail due to torsional stress which is not parallel to the rail direction, so that the gantry crane cannot normally operate, and constructors must correct the problem of the gantry crane, but under the condition, structural correction is inconvenient to actually carry out on a large structure which is built in a foundation pit, otherwise, a large amount of engineering expenditure and engineering progress are consumed; the method has the advantages that the direct structure of the stress which is hard to bear on the gantry crane is broken under the condition of heavier degree, or the support legs of the gantry crane are directly derailed from the rails on the two sides, and then the gantry crane is hammered into the foundation pit in a very short time, so that major safety accidents are caused.

However, the present embodiment solves the above problem well by moving the installation position of the gantry crane rail to the position of the existing ground 007 outside the foundation pit. Firstly, the state attribute of the gantry crane is directly unhooked from various conditions in the foundation pit, compared with a foundation pit with a complicated and changeable structure state along with construction, the ground 007 has considerable state stability because a relatively stable structure is formed and basically does not belong to the construction category, so that the gantry crane cannot be influenced by almost any construction operation in the foundation pit and natural change of the foundation pit, and has considerable safety, use stability and easy maintainability, thereby being beneficial to promoting the construction progress and more reasonable distribution of construction resources. Meanwhile, the influence of the gantry crane on the crown beam 002 and the support is directly cleared, and an extra redundant structure is not required to be arranged or a related structure is not required to be maintained all the time, so that the engineering resources can be used in construction projects with higher priority. In addition, the correction of the gantry crane track is relatively simpler because the gantry crane track is positioned on the side with more stable structure. Simultaneously, still directly will be used for erectting orbital crown beam 002 headspace and give way originally with portal crane orbit migration to the foundation ditch outside, this scheme has set up the obturator 003 and the retaining wall 005 that the collection joined in marriage the backfill then on this vacant space.

Backfill occupies a part with the top of crown beam 002, produce the higher grit obturator 003 of density based on backfilling, shelter from and the simplification with the foreign matter and the external force influence at crown beam 002 top at first for crown beam 002 top can not receive rainfall, unexpected drop, the external force influence to crown beam 002 top that engineering misoperation caused, make the structural integrity at crown beam 002 top can be guaranteed, still made further assurance to crown beam 002's structural integrity outside the hidden danger that release crown beam 002 bore portal crane ground roof beam 008. Secondly, the backfill layer enhances the uniformity of the basic supporting force of the crown beam 002 in the height direction, so that the backfill layer can bear the construction of a high layer (namely the existing ground 007 layer) in a stronger and more stable manner.

The backfill provides additional shielding stability in the horizontal direction for the guide wall 004, and in the conventional scheme, particularly when the crown beam 002 is arranged to be lower than the existing ground 007, the part of the guide wall 004 close to the foundation pit wall is exposed outside, and the part is firstly easily affected by other devices working in the foundation pit, such as damage to the part caused by construction operation error in the foundation pit.

Meanwhile, one side of the guide wall 004 on the horizontal plane is easily subjected to lateral displacement force in the horizontal direction generated by pressure from the approximately vertical direction on the stratum soil, the force is particularly huge when a gantry crane ground beam 008 and a rail are arranged above the guide wall 004 and then the gantry crane is driven to pass through, and if the horizontal lateral displacement force is not blocked, the lateral displacement of the guide wall 004, even the rupture of the guide wall 004 in the direction, is easily caused, so that the stable fixing effect on the foundation pit slope is lost, and the slope collapse is caused. And the overhead part of the crown beam 002 is emptied, so that a filling body 003 can be arranged to block one side of the guide wall 004 at the side of the foundation pit to a certain extent, and the structural protection of the guide wall 004 is additionally realized.

The centralized backfill is a mixture of soil and stones, has relatively soft texture and a certain elastic absorption effect, is arranged at one side close to the ground beam, can absorb part of vibration of the ground beam 008 of the gantry crane, and actually tamps a backfill area in the running process of the gantry crane, so that the structure is more stable and firmer;

the gravity type retaining wall 005 can be used at the top of the top beam 002, so that a large amount of tamping work is not needed, the phenomenon of slip of backfilled soil is avoided, particularly, the gravity of the gantry crane is pressed and transmitted to the application force in the horizontal plane direction at the top, and if the gravity type retaining wall 005 is not adopted, the filled soil is easy to slip, the ground beam is loosened, and the problems of derailment and the like are caused. The top beam 002 has excellent stability as a foundation, and can be just used as a construction foundation of the gravity retaining wall 005, and the retaining wall 005 simultaneously provides additional compaction action for the stability of the top beam 002 and the support at the bottom of the top beam 002 in the horizontal direction by the gravity of the retaining wall.

Meanwhile, a cushion layer 006 and an additional drainage ditch 009 can be arranged above the filler 003, and in the conventional scheme, because the top of the crown beam 002 is occupied by the gantry crane ground beam 008, the part has no resistance to foreign matters from the top space of the crown beam 002, especially for accumulated water falling from the top, such as rainwater or accumulated water flowing out from the edge of a foundation pit, the top of the crown beam 002 is flushed by water, and meanwhile, because a plurality of supports below the crown beam 002 occupy the space, no better scheme is provided with drainage measures, and finally the accumulated water of the crown beam 002 and the support position below the crown beam 002 is serious.

Set up the track at the foundation ditch periphery outside guan liang 002 for guan liang 002 headspace is liberated, the space that has been backfilled and lift to the position on ground at guanliang 002 simultaneously given, make the drainage course that can participate in foundation ditch week side under the condition that does not receive guanliang 002 influence of escape canal 009 originally, further promote the prevention of seepage water stability of foundation ditch side slope, compare in the conventional scheme with the track setting in guanliang 002 top, this scheme has realized preventing to the infiltration.

It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of the present disclosure, may devise various arrangements that are within the scope of the present disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents. The present description contains several inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", each indicating that the respective paragraph discloses a separate concept, the applicant reserves the right to submit divisional applications according to each inventive concept.

Claims (10)

1. A construction method of a ground beam of a portal crane at the edge of a deep foundation pit,

it is characterized in that the preparation method is characterized in that,

comprises the following steps of (a) carrying out,

grading backfill is carried out on a gap space near an inclined wall of a retaining wall (005) before construction of a gantry crane ground beam (008), the gantry crane ground beam (008) is poured on a filling body (003), a main reinforcement protective layer and a temperature gap are arranged, an embedded part is arranged on the gantry crane ground beam (008), a gantry crane walking track is arranged on the gantry crane ground beam (008) under the coordination of the embedded part,

in the direction of being horizontal to the ground, portal crane ground beam (008) compare keep away from deep basal pit more than retaining wall (005), and lie in present situation ground (007) at deep basal pit edge.

2. The method as claimed in claim 1, wherein the lower end of the retaining wall (005) is provided on a crown beam (002), and the crown beam (002) is constructed by constructing a plurality of diaphragm walls (001) to be communicated with each other at the top.

3. A method according to claim 1 or 2, characterized in that the diaphragm wall (001) is arranged in a deep groove made in the soil around the edge of the deep foundation pit.

4. A method according to any one of claims 1 to 3, wherein the width of the bottom of the retaining wall (005) is smaller than the width of the top of the crown beam (002), and the retaining wall (005) is provided at a position on the deep foundation pit side of the top of the crown beam (002).

5. A method according to any of claims 1-4, characterized in that the other side of the crown beam (002) from the side of the deep foundation pit is in contact with a guide wall (004), the guide wall (004) having at least a first guide wall (004) face and a second guide wall (004) face perpendicular to each other, the first guide wall (004) face being horizontal to the ground and having at least one portion arranged below the existing ground (007), the second guide wall (004) face being perpendicular to the ground and being in contact with the crown beam (002).

6. A method according to any one of claims 1 to 5, wherein the portion of the second guide wall (004) beyond the contact to the crown beam (002) and the inclined wall of the retaining wall (005) form the clearance space therebetween.

7. A method according to any one of claims 1 to 6, characterized in that the interstitial spaces are of a trapezoidal configuration with a short upper base contacting the crown beam (002) and a long lower base remote from the crown beam (002), the infill (003) backfilled in such spaces being of a uniform configuration.

8. A method according to any one of claims 1 to 7, wherein the lower bottom of the infill (003) is coplanar with and parallel to the horizontal plane of the first guide wall (004), and above both is provided a bedding layer (006).

9. The method according to any one of claims 1 to 8, wherein the gantry crane ground beam (008) is arranged on the bedding (006), and the sum of the height of the gantry crane ground beam (008) in the vertical direction and the thickness of the bedding (006) is equal to the vertical distance from the surface of the existing ground (007) to the surface of the first guide wall (004).

10. The method according to any one of claims 1 to 9, wherein the gantry crane ground beams (008) are provided on one side close to the existing ground (007) and the pads on the other side thereof are provided with drains (009) in contact with the sides thereof.

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