High and steep slope reinforcing system with slope crest adjacent to post-built municipal pipe gallery and construction method of high and steep slope reinforcing system

Abstract

The invention provides a high and steep slope reinforcing system with a slope crest adjacent to a post-built municipal pipe gallery and a construction method of the high and steep slope reinforcing system. The reinforcing system comprises an original side slope lattice anchor supporting structure, a pipe gallery structure, a foam concrete backfill structure located on the side, close to the original side slope surface, of the pipe gallery structure, a row of newly-added anchor rods / cables constructed below the first row of original anchor rods / cables below the slope top, and a row of miniature steel pipe piles constructed below the outer side, close to the side slope surface, of the pipe gallery structure. A first row of anchor rods (cables) of an original removed side slope support are replaced by newly added anchor rods or anchor cables, and the whole steel pipe piles are located in the foam concrete to form a miniature pile retaining wall structure. The overall stability of the high and steep slope with the slope crest adjacent to the pipe gallery is greatly improved, and displacement of the slope crest adjacent to the pipe gallery is effectively controlled; the settlement of the slope crest adjacent to the pipe gallery is effectively controlled in a design and standard range; meanwhile, the foam concrete structure is used for filling the pipe ditch (groove), so that filling pressure can be reduced, and compactness and strength are guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of high-steep slope treatment projects and the reinforcement of municipal pipe galleries adjacent to the top of the slope, and particularly relates to a high-steep slope reinforcement system and construction method for a post-constructed municipal pipe gallery closely adjacent to the top of the slope. Technical Background

[0002] With the rapid development of society, the utilization rate of space in urban municipal construction, industrial factories or storage sites, etc. is getting higher and higher, and they are often built on hilly or mountainous terrains, thus forming artificial high-steep slopes. Due to the serious lag in the overall planning and the poor handover of land use planning materials between the two parties because the adjacent sites belong to different owners, the situation where the original slope support system fails to consider the newly planned municipal pipe gallery closely adjacent to the top of the slope appears. Especially in the case where the already constructed original slope support system conflicts with the post-constructed municipal pipe gallery closely adjacent to the top of the slope, it is necessary to cancel the upper 1 - 2 rows of anchor rods (cables). Municipal shallow-buried pipe galleries generally adopt the open-cut and backfill method. The pipe gallery is a displacement-sensitive structure. If the upper anchor rods (cables) are directly cancelled without reinforcement measures or the reinforcement measures are improper, and over time, with the increase of the load on the top of the slope, rainfall and other reasons, the slope displacement collapses or even develops into overall instability, and the settlement of the ground surface on the top of the slope increases, which is likely to cause the settlement and deformation of the foundation of the pipe gallery adjacent to the top of the slope, leaving a great potential safety hazard for the long-term stability of the slope and the normal operation of the pipe gallery.

[0003] In view of the above situation, the traditional solutions mainly include the following methods: (1) Communicate with the owner of the pipe gallery to change the design route of the pipe gallery. In this case, since the planned municipal pipe gallery includes various types of pipelines such as electricity and signals, there is no space to change the route or the impact of changing the route on the regional power supply dispatching and other municipal pipelines is too large, and the overall change cycle is very long; (2) Change the design scheme of the affected original slope support section, and adopt anti-slide piles + columns + multiple rows of long cables + retaining plates, and then backfill the roadbed, build the pipe gallery and the road facilities on the top of the slope. This scheme is expensive, has a long construction period, has a large amount of earthwork excavation and filling, and the disturbance of the original soil greatly exacerbates the slope instability. The upper cables are likely to conflict with the main structure and foundation of the pipe gallery adjacent to the top of the slope, thus posing a great threat to the normal operation of the road on the top of the slope, especially the displacement-sensitive municipal pipe gallery. Summary of the Invention

[0004] Aiming at the deficiencies and defects of the prior art, the present invention provides a high-steep slope reinforcement system and construction method for a post-constructed municipal pipe gallery closely adjacent to the top of the slope. The present invention can improve the overall stability of the high-steep slope closely adjacent to the pipe gallery at the top of the slope, and effectively control the displacement and settlement of the pipe gallery closely adjacent to the top of the slope within the design and specification ranges.

[0005] In order to achieve the above technical objectives, the present invention provides a high-steep slope reinforcement system with a municipal utility tunnel constructed adjacent to the gable roof. The system includes an original slope lattice anchor support structure constructed on the original slope surface and a tunnel structure constructed on the top of the original slope. The tunnel structure is adjacent to the original slope surface. The reinforcement system further includes an excavation and backfill structure on the side of the tunnel structure adjacent to the original slope surface, a row of new bolts or cables constructed below the first row of original bolts or cables under the top of the original slope, and a row of micro steel pipe piles constructed below the outer side of the tunnel structure on the top of the original slope adjacent to the slope surface. The excavation and backfill structure is a retaining structure formed by excavating and backfilling foamed concrete on the side of the tunnel structure adjacent to the original slope surface. The driving angle of the new bolts or cables is 30° - 35°, and the foundation or cushion of the tunnel structure is avoided. The spacing of the micro steel pipe piles is 1.0 - 2.0 m, and the pile top area is buried in the excavation and backfill structure.

[0006] A preferred technical solution of the present invention: The original slope lattice anchor support structure includes a reinforced concrete square lattice beam formed by formwork pouring on the slope surface of the original slope after slope excavation, and original bolts or cables driven into the slope from the intersection of each longitudinal lattice beam and transverse lattice beam of the square lattice beam. A capping beam is provided at the top of the original slope, and a bottom sealing beam and a drainage structure are provided at the bottom of the original slope. The capping beam is close to the land use red line. The horizontal and vertical spacing of the original bolts or cables is 2.0 - 3.5 m, and the driving angle is 20° - 25°. The new bolts or cables replace the first row of original bolts or cables under the top of the original slope. A new longitudinal beam is provided on the vertical center line of each lattice frame of the first row of square lattice beams under the top of the original slope. The new bolts or cables are driven into the slope from the center of each new longitudinal beam.

[0007] A preferred technical solution of the present invention: The micro steel pipe piles adopt grouted steel pipe piles. The steel pipe piles are arranged at equal intervals. The pile diameter of a single steel pipe pile is 110 - 300 mm, and slurry outlet holes with a diameter of 15 mm are arranged in a spiral pattern at equal intervals on the pipe wall. The axial spacing between adjacent two slurry outlet holes is 30 - 50 cm.

[0008] A preferred technical solution of the present invention: The tunnel structure includes a tunnel trench and a tunnel main structure buried in the tunnel trench. A crushed stone or concrete tunnel cushion is provided at the bottom of the tunnel trench. The buried depth of the tunnel cushion is 1.6 - 3.5 m. The tunnel main structure is close to the land use red line and adopts open cut foundation pit support. Soil and stone backfill layers are formed by backfilling soil and stones on the inner side of the tunnel main structure away from the slope surface. The side of the tunnel main structure adjacent to the slope surface is adjacent to the excavation and backfill structure.

[0009] Preferred technical solution of the present invention: Both the original anchor rods or cables and the newly added anchor rods or cables are ordinary steel bar anchor rods, prestressed steel bar anchor rods or prestressed steel strand cables; the specifications of the newly added anchor rods or cables are the same as those of the original anchor rods or cables, and the length of the newly added anchor rods or cables is equal to or greater than the length of the original anchor rods or cables.

[0010] To achieve the above technical objectives, the present invention also provides a construction method for a high-steep slope reinforcement system with a municipal utility tunnel built adjacent to the top of the slope, characterized in that the specific construction steps are as follows:

[0011] S1. According to the design drawings of the municipal utility tunnel structure and its pipe trench, overlay the design plan position, elevation of the municipal utility tunnel structure and its pipe trench with the design drawing of the original slope lattice anchor support structure, and evaluate and confirm the scope of the affected constructed original slope top anchor rods or cables and lattice beams; and according to the sectional view and elevation view after overlay, determine the reinforcement design plan; the reinforcement design includes setting a new longitudinal beam in the middle of each lattice frame above the first row of anchor rods or cables affected by the original slope lattice anchor support structure, setting new anchor rods or cables in the middle of each new longitudinal beam, and adding a row of vertical grouting steel pipe piles between the outside of the slope top tunnel structure and the capping beam. The diameter of each steel pipe pile is 110 - 300 mm, the spacing between adjacent two steel pipe piles is 1.0 - 2.0 m, and the pile length of each steel pipe pile embedded in the slope soil at the bottom of the pipe trench of the municipal utility tunnel structure is not less than 2 times the pile length above the bottom of the pipe trench.

[0012] S2. According to the reinforcement design drawing drawn in step S1, construct a row of new anchor rods or cables at the design positions of the new anchor rods or cables. The driving angle of the new anchor rods or cables is 30 - 35°, and avoid the foundation or cushion of the municipal utility tunnel structure, and then remove the first row of anchor rods or cables affected by the original slope lattice anchor support structure.

[0013] S3. Remove the slope top lattice beam and capping beam affected by the pipe trench excavation range, and then excavate the pipe trench from the ground according to the design drawings of the municipal utility tunnel structure and its pipe trench, carry out temporary support for the pipe trench, and successively carry out the construction of laying the cushion, pouring the foundation and the tunnel main body in the pipe trench to complete the overall construction of the tunnel structure.

[0014] S4. Construct the new vertical grouting steel pipe piles, drill holes from the position between the outside of the constructed tunnel structure and the capping beam, drive in the steel pipe piles and grout. The construction of the vertical grouting steel pipe piles avoids the anchor rods or cables.

[0015] S5. Carry out symmetric backfilling on both sides of the pipe trench. The inner backfilling material away from the slope surface is soil mixed with stones, and the outer side close to the slope surface is formwork-supported and foam concrete is poured in layers, and both are densely backfilled to the ground.

[0016] S6. After the foam concrete structure is cured to 80% of the designed strength, construct the newly added longitudinal beams, and construct the lattice beams and capping beams on the slope top that were demolished in step S3, and restore the affected drainage holes and greening;

[0017] S7. After the newly added longitudinal beams, lattice beams on the slope top and capping beams in step S6 are cured to 80% of the designed strength, seal the anchors of the newly added rock bolts or cable bolts constructed in step S2 to complete the construction of the slope top reinforcement structure system; when the newly added rock bolts or cable bolts are prestressed rock bolts or cable bolts, tension the rock bolts or cable bolts according to the design parameters and lock them, and then pour concrete for anchor sealing; when the newly added rock bolts are ordinary steel bar rock bolts, directly pour concrete for anchor sealing;

[0018] S8. After the construction of the slope top reinforcement structure system is completed, construct the slope top road and its ancillary structures.

[0019] The preferred technical solution of the present invention: When determining the reinforcement design plan in step S1, verify and determine the best construction parameters of the micro steel pipe piles according to the overall stability theory of the traditional slope lattice anchor support and the theory of controlling the slope top displacement by micro piles. The specific steps are as follows:

[0020] a. Set each construction parameter of the micro steel pipe piles according to the steel pipe pile specifications in engineering experience. The construction parameters of the micro steel pipe piles include the material, pile diameter and wall thickness of the steel pipe piles;

[0021] b. Calculate the top displacement of the micro steel pipe pile group through the above-set parameters, and compare the calculated top displacement of the micro steel pipe pile group with the maximum slope top displacement that meets the design and specifications. If it is less than the maximum slope top displacement of the design and specifications, the above parameters meet the construction requirements;

[0022] The calculation process of the top displacement of the micro steel pipe pile group is as follows:

[0023] Regard a single micro steel pipe pile as a flexural "cantilever beam", and first calculate the top displacement of a single micro steel pipe pile according to the following formula:

[0024]

[0025] I = π(D^4 - d^4) / 64

[0026] Where: σ—theoretical horizontal displacement at the top of a single micro steel pipe pile; q0—uniform soil pressure behind the pile;

[0027] H—the length above the anchorage section of the pile body; E—elastic modulus of the micro steel pipe pile;

[0028] I—inertia moment of the micro steel pipe pile; D and d are the outer diameter and inner diameter of the steel pipe pile respectively;

[0029] Among them, the values of E and I are fixed after the steel pipe pile material specifications are determined;

[0030] Then, calculate the top displacement of the micro steel pipe pile group according to the following formula:

[0031]

[0032] K - correction coefficient, K is considered to take 1.1 - 1.3.

[0033] A preferred technical solution of the present invention: In the S1 step, the original slope lattice anchor support structure is constructed according to the slope ratio of the original slope design drawing, and the overall construction follows the principle of from top to bottom. The construction steps successively include: slope earth excavation, slope surface trimming, construction of drainage ditches and drain holes, construction of anchor rods or cables, construction of lattice beams, tensioning, locking and sealing of prestressed anchor rods or cables, and slope surface grass planting and greening; The constructed original slope lattice anchor support structure includes a reinforced concrete square frame beam and original anchor rods or cables driven into the slope from the intersection of the longitudinal and transverse lattice beams of the reinforced concrete square frame beam. There is a capping beam at the top of the original slope, and a bottom sealing beam and a drainage and water intercepting structure at the bottom of the original slope. The capping beam is close to the land use red line; The horizontal and vertical spacing of the original anchor rods or cables is 2.0 - 3.5m, and the driving angle is 20° - 25°.

[0034] A preferred technical solution of the present invention: In the S2 step, the newly added anchor rods or cables replace the first row of anchor rods or cables affected by the removed original slope lattice anchor support structure, and the newly added anchor rods or cables are driven into the slope from the central part of each newly added longitudinal beam; The newly added anchor rods or cables have the same specifications as the first row of anchor rods or cables of the original slope lattice anchor support structure, and the length is equal to or greater than the length of the first row of anchor rods or cables of the original slope lattice anchor support structure.

[0035] A preferred technical solution of the present invention: In the S4 step, the vertical grouting steel pipe piles are arranged at equal intervals, and slurry outlet holes are arranged in a spiral pattern at equal intervals on the pipe wall of each steel pipe pile, with a hole diameter of 15mm and an axial spacing of 30 - 50cm.

[0036] The beneficial effects of the present invention:

[0037] (1) The present invention maximally utilizes the slope support structure system designed and constructed originally, takes measures to lower the elevation and shift the position of the anchor rods (cables) within the influence range of the pipe gallery excavation at the slope top, avoids the pipe gallery main body and its cushion foundation by adjusting the driving angle, disturbs the slope soil as little as possible, improves the overall stability of the high and steep slope adjacent to the pipe gallery at the slope top, and effectively controls the slope top displacement.

[0038] (2) The backfill of the slope top trench of the present invention uses foam concrete materials for layered backfill, which has the advantages of light weight, high strength, and high filling density compared with the traditional earthwork backfill. It can reduce the overall soil pressure of the slope and is integrally cast with the vertical micro steel pipe piles, increasing the anti-deformation strength of the concrete filling material and effectively reducing the post-construction settlement and deformation of the slope top.

[0039] (3) By using the mechanism of the micro steel pipe piles to control the displacement of the slope top in the present invention, the displacement value of the slope top can be quickly estimated, and the design size and specifications of the steel pipe piles can also be quickly rechecked according to the design and specification allowable values of the slope top displacement; and based on the overall connection of the steel pipe piles - foam concrete and the comprehensive stiffness amplification effect of the newly added anchor rods (cables) on the "micro steel pipe pile retaining wall" in the reinforcement system of the present invention, reasonable corrections are further made on the above theoretical basis to effectively ensure that the slope top displacement is controlled within the design and specification ranges, thereby further reducing the settlement of the slope top near the pipe gallery and the road and reducing the uneven settlement.

[0040] (5) Compared with the traditional column piles (double-row piles) + multi-row long and deep anchor cables scheme, the present invention reduces the amount of earthwork excavation and filling and the serious disturbance to the original soil body, greatly saves the cost and construction period, and avoids the conflict between the upper anchor cables of the conventional pile-anchor scheme and the main structure and foundation of the pipe gallery near the slope top. The support structure system of the present invention is reasonable and the construction is convenient, enhancing the overall slope safety and stability, and generally improving the treatment and reinforcement benefits of the high-steep slope of the pipe gallery built later adjacent to the slope top. Description of the Drawings

[0041] Figure 1 is the sectional view of the high-steep slope reinforcement system of the pipe gallery built later adjacent to the slope top of the present invention;

[0042] Figure 2 is the original design sectional view of the municipal high-steep slope of the present invention;

[0043] Figure 3 is the detailed drawing of the slope top structure of the high-steep slope reinforcement system of the pipe gallery built later adjacent to the slope top of the present invention;

[0044] Figure 4 is the elevation view of the high-steep slope reinforcement system of the pipe gallery built later adjacent to the slope top of the present invention;

[0045] Figure 5 is the top view of the high-steep slope reinforcement system of the pipe gallery built later adjacent to the slope top of the present invention;

[0046] Figure 6 is the simplified force diagram of the micro steel pipe piles in the present invention.

[0047] In the figure: 1 - slope, 100 - slope top, 2 - excavation support and backfill structure, 3 - newly added anchor rod or cable, 4 - square frame beam, 400 - newly added longitudinal beam, 5 - pipe gallery structure, 500 - pipe gallery trench, 501 - pipe gallery main structure, 502 - pipe gallery cushion, 503 - soil and stone backfill layer, 6 - micro steel pipe pile, 7 - original anchor rod or cable, 8 - capping beam, 9 - bottom sealing beam, 10 - drainage structure, 11 - original terrain line, 12 - land use red line, 13 - slope surface drain hole, 14 - slope surface greening, 15 - slope top road structure. Specific implementation manners

[0048] The present invention will be further described below with reference to the accompanying drawings and embodiments. The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figures 1 to 6 These are all the drawings of the embodiments, which are drawn in a simplified manner and are only used to clearly and concisely illustrate the purpose of the embodiments of the present invention. The technical solutions shown in the drawings below are the specific solutions of the embodiments of the present invention and are not intended to limit the scope of the present invention to be protected. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present invention is normally placed, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0050] The embodiment of the present invention provides a high-steep slope reinforcement system with a post-constructed municipal pipe gallery adjacent to the slope top, such as Figure 1 , Figures 3 to 5As shown in the figure, it includes the original slope lattice anchor support structure constructed on the slope surface of the original slope 1 and the pipe gallery structure 5 constructed on the top of the original slope 1. The pipe gallery structure 5 is adjacent to the slope surface of the original slope 1. The original slope lattice anchor support structure includes the reinforced concrete square lattice beams 4 formed by formwork pouring on the slope surface of the original slope 1 after slope excavation and the original anchor rods or cables 7 driven into the slope from the intersection of each longitudinal lattice beam and transverse lattice beam of the square lattice beams 4. There is a capping beam 8 at the top of the original slope 1, and a bottom sealing beam 9 and a drainage structure 10 at the bottom of the original slope 1. The capping beam 8 is close to the land use red line 12; the horizontal and vertical spacing of the original anchor rods or cables 7 is 2.0 - 3.5 m, and the driving angle is 20° - 25°; the new anchor rods or cables 3 replace the first row of original anchor rods or cables below the top of the original slope 1. There is a new longitudinal beam 400 on the vertical bisector of each lattice frame of the first row of square lattice beams 4 at the top of the original slope 1. The new anchor rods or cables 3 are driven into the slope from the center of each new longitudinal beam 400. The reinforcement system also includes the excavation and backfill structure 2 on the side of the pipe gallery structure 5 adjacent to the slope surface of the original slope 1, a row of new anchor rods or cables 3 constructed below the first row of original anchor rods or cables 7 at the top of the original slope 1, and a row of micro steel pipe piles 6 constructed below the outer side of the pipe gallery structure 5 at the top of the original slope 1 adjacent to the slope surface; the excavation and backfill structure 2 is a retaining structure formed by excavating and backfilling foam concrete on the side of the pipe gallery structure 5 adjacent to the slope surface of the original slope 1. The driving angle of the new anchor rods or cables 3 is 30 - 35°, and it avoids the foundation or cushion layer of the pipe gallery structure 5; the spacing of the micro steel pipe piles 6 is 1.0 - 2.0 m, and the pile top area is buried in the excavation and backfill structure 2.

[0051] In the embodiment, the micro steel pipe piles 6 adopt grouted steel pipe piles. The steel pipe piles are arranged at equal intervals. The pile diameter of a single steel pipe pile is 110 - 300 mm. The slurry outlet holes with a diameter of 15 mm are arranged in a spiral pattern at equal intervals on the pipe wall, and the axial spacing between adjacent two slurry outlet holes is 30 - 50 cm. The pipe gallery structure 5 includes a pipe gallery trench 500 and a pipe gallery main structure 501 buried in the pipe gallery trench 500. There is a gravel or concrete pipe gallery cushion 502 at the bottom of the pipe gallery trench 500, with a buried depth of 1.6 - 3.5 m. The pipe gallery main structure 501 is close to the land use red line 12 and adopts open cut foundation pit support. A soil and stone backfill layer 503 is formed by backfilling soil and stones on the inner side of the pipe gallery main structure 501 away from the slope surface. The side of the pipe gallery main structure 501 adjacent to the slope surface is adjacent to the excavation and backfill structure 2. The original anchor rods or cables 7 and the new anchor rods or cables 3 both adopt ordinary steel bar anchor rods or prestressed steel bar anchor rods or prestressed steel strand cables; the specifications of the new anchor rods or cables 3 are the same as those of the original anchor rods or cables 7, and the length of the new anchor rods or cables 3 is equal to or greater than the length of the original anchor rods or cables 7.

[0052] The present invention has a wide range of applications. It is applicable to the situation where the original slope support system fails to consider the newly added planning adjacent to the municipal utility tunnel at the slope top due to the serious lag of municipal planning. In particular, for the existing slope support system that needs to cancel the upper 1 - 2 rows of anchor bolts (cables) due to conflicts with the newly built municipal utility tunnel adjacent to the slope top, an economic, practical, and convenient reinforcement system and construction method are proposed to ensure the permanent stability during the construction process and operation stage and the long - term safe operation of the utility tunnel.

[0053] Taking the slope top of a certain industrial park adjacent to a municipal road and a power utility tunnel as an example, the construction method of the high - steep slope reinforcement system adjacent to the newly built municipal utility tunnel at the slope top is as follows. The specific design and construction steps are as follows:

[0054] Original slope design and construction steps: According to the slope ratio of the original slope design drawing, carry out the normal construction process of slope lattice anchors: slope earth excavation, slope surface trimming - construction of drainage ditches and drain holes - simultaneous construction of anchor cables - construction of lattice beams - tensioning, locking, and sealing of prestressed anchor cables - slope surface grass planting and greening. The overall slope excavation and support construction follow the principle of from top to bottom;

[0055] After obtaining the planning data drawings of the municipal utility tunnel adjacent to the slope top from the road right - of - way owner and having full communication, it is finally disagreed to relocate. The designers and the technical personnel of the project department consider carrying out slope top reinforcement design and construction for the existing original slope. The specific steps are as follows:

[0056] S1. According to the structure of the municipal utility tunnel and its trench design drawings, overlay the design plan position, elevation of the municipal utility tunnel structure and its trench with the original slope lattice anchor support structure design drawing to evaluate and confirm the scope of the affected existing original slope top anchor bolts or cables and lattice beams; the slope top reinforcement design specifically determines the reinforcement design plan according to the sectional view and elevation view after overlaying. The reinforcement design is constructed on the original slope lattice anchor support structure, and the original slope lattice anchor support structure is constructed according to the slope ratio of the original slope design drawing, and its overall construction follows the principle of from top to bottom. The construction steps successively include: slope earth excavation, slope surface trimming, construction of drainage ditches and drain holes, construction of anchor bolts or cables, construction of lattice beams, tensioning, locking, and sealing of prestressed anchor bolts or cables, slope surface grass planting and greening; the completed original slope lattice anchor support structure includes reinforced concrete square frame beams and the original anchor bolts or cables driven into the slope from the intersection of the longitudinal and transverse lattice beams of the reinforced concrete square frame beams. There is a capping beam at the original slope top, and a bottom - sealing beam and a drainage and water - intercepting structure at the bottom of the original slope. The capping beam is close to the land use red line; the horizontal and vertical spacing of the original anchor bolts or cables is 2.0 - 3.5 m, and the driving angle is 20° - 25°.

[0057] The reinforcement design includes setting an additional longitudinal beam in the middle of each lattice frame above the first row of bolts or cables affected by the original slope lattice anchor support structure. The specifications and steel bar reinforcement of the additional longitudinal beam are the same as those of the longitudinal lattice beam of the original designed slope lattice frame. An additional bolt or cable is set in the middle of each additional longitudinal beam. The specifications of the cable are the same as those of the original first row of affected cables, and the length can be appropriately extended. The driving angle is adjusted appropriately to avoid the pipe gallery foundation or cushion adjacent to the slope top, and adjusted to 35°. The vertical steel pipe piles are arranged at equal intervals. The pile hole diameter is 230mm, the steel pipe diameter is 210mm, the pipe wall thickness is 6mm, the grouting material is M30 cement mortar, the spacing between adjacent two steel pipe piles is 1.0m, and the slurry outlet holes are arranged in a spiral pattern at equal intervals on the pipe wall, with a hole diameter of 15mm and an axial spacing of 30cm. And the length of each steel pipe pile embedded in the slope soil body at the bottom of the pipe trench of the municipal pipe gallery structure is not less than 2 times the length of the pile above the bottom of the pipe trench;

[0058] According to the overall stability theory of the traditional slope lattice anchor support and the theory of using micropiles to control the displacement of the slope top, determine the material, pile diameter and wall thickness of the micro steel pipe piles; calculate the pile top displacement of the steel pipe piles according to the above parameters, and compare the calculated pile top displacement of the steel pipe piles with the maximum displacement of the slope top that meets the design and specifications. If it is less than the maximum displacement of the slope top of the design and specifications, then the above parameters meet the construction requirements; if not, it can be reset by changing different steel pipe models. The calculation process of the pile top displacement of the steel pipe column is as follows:

[0059] Regard a single micro steel pipe pile as a flexural "cantilever beam", and first calculate the pile top displacement of a single micro steel pipe pile according to the following formula:

[0060]

[0061] I = π(D^4 - d^4) / 64

[0062] Where: σ—theoretical horizontal displacement at the pile top of a single micro steel pipe pile; q0—uniform soil pressure behind the pile;

[0063] H—the length above the anchorage section of the pile; E—elastic modulus of the steel pipe micro pile;

[0064] I—inertia moment of the steel pipe micro pile; D and d are the outer diameter and inner diameter of the steel pipe pile respectively;

[0065] Where the values of E and I are fixed values after the material specifications of the steel pipe pile are determined;

[0066] Where the specifications of the steel pipe piles are preset according to engineering experience, the pile length is 7.5m, the cantilever section is 2.2m, the embedded section is 5.3m, the pile hole diameter is 230mm, the steel pipe diameter is 210mm, the pipe wall thickness is 6mm, and the flexural rigidity EI value can be obtained by querying relevant engineering tables as 4004 KN*m 2; q0 is the average earth pressure borne by the cantilever section (upper part of the anchoring section) of the steel pipe pile along the pile body (additional loads such as driving on the slope top road are taken into account during calculation). It can be calculated according to the conventional soil mechanics formula. The standard value of active earth pressure strength is the standard value of vertical stress multiplied by the active earth pressure coefficient. H is the length of the cantilever section (upper part of the anchoring section) of the steel pipe pile. In the present invention, it is the height of the steel pipe pile above the bottom of the corridor foundation trench. According to the results of soil mechanics analysis, q0 is 16kN / m 2 ; H is taken as 2.2m. After calculation, the theoretical horizontal displacement σ of a single micro steel pipe pile is 8.76mm.

[0067] The maximum bending horizontal displacement of a single micro steel pipe pile is calculated according to the above formula. In the present invention, the micro steel pipe pile group is connected together by concrete pouring, and the integrity is strengthened. The overall stiffness effect is greater than that of a single micro steel pipe pile, and the maximum bending horizontal displacement of the whole will be reduced to a certain extent. It is necessary to make appropriate corrections to the above formula; the top displacement of the micro steel pipe pile group after correction is calculated as follows:

[0068]

[0069] K—correction coefficient, K is 1.1~1.3

[0070] K takes into account the following factors: (1) The foam concrete is poured above the anchoring section of the grouting steel pipe pile as a whole, which plays a connecting beam role for the steel pipe pile as a whole; (2) The additional anchor cable is located above the anchoring section of the steel pipe pile, and in particular, the prestressed anchor cable transmits the horizontal component of force perpendicular to the steel pipe pile through the lattice beam frame and the slope surface, which plays a role in limiting the overall horizontal displacement of the "micro steel pipe pile retaining wall". The above factors all play an equivalent role in amplifying the stiffness of the steel pipe pile. The K of the grouting steel pipe pile of the present invention is considered to be 1.2.

[0071] After adjustment, the theoretical horizontal displacement σ* of the pile top is 7.3mm, which fully meets the design and specification requirements that the maximum displacement of the slope top does not exceed 10mm; thus, it is confirmed that all design parameters meet the design requirements.

[0072] S2. According to the reinforcement design drawing drawn in step S1, construct a row of new anchor rods or anchor cables at the designed position of the new anchor rods or anchor cables, with the driving angle of the new anchor rods or anchor cables being 30 to 35 degrees, and avoiding the foundation or cushion layer of the municipal pipe gallery structure, and then remove the first row of affected anchor rods or anchor cables of the original slope lattice anchor support structure; replace the first row of affected anchor rods or anchor cables of the original slope lattice anchor support structure with new anchor rods or anchor cables, and the new anchor rods or anchor cables are driven into the slope from the center of each new longitudinal beam; the new anchor rods or anchor cables have the same specifications as the first row of anchor rods or anchor cables of the original slope lattice anchor support structure, and the length is equal to or greater than the length of the first row of anchor rods or anchor cables of the original slope lattice anchor support structure.

[0073] S3. Demolish the lattice beams and capping beams at the slope top affected by the excavation range of the pipe trench. Then, excavate the pipe trench from the ground according to the municipal pipe gallery structure and its pipe trench design drawings, carry out temporary support (protection) for the pipe trench, and successively construct the cushion layer laying, foundation pouring and pipe gallery main body in the pipe trench to complete the overall construction of the pipe gallery structure;

[0074] S4. Construct the newly added vertical grouting steel pipe piles. Drill holes at the position between the outer side of the completed pipe gallery structure and the capping beam, drive the steel pipe piles and grout. The construction of the vertical grouting steel pipe piles avoids the anchor bolts or anchor cables; In step S4, the vertical grouting steel pipe piles are arranged at equal intervals, and the slurry outlet holes are arranged in a spiral pattern at equal intervals on the pipe wall of each steel pipe pile, with a hole diameter of 15 mm and an axial spacing of 30 cm.

[0075] S5. Carry out symmetrical backfilling on both sides of the pipe trench. The inner backfilling material far from the slope surface is soil mixed with stones, and the outer side near the slope surface is formwork-supported and foamed concrete is poured in layers, and both are densely backfilled to the ground.

[0076] S6. After the foamed concrete structure is cured to reach 80% of the design strength, construct the newly added longitudinal beams, and construct the lattice beams and capping beams at the slope top removed in step S3, and restore the affected drain holes and greening.

[0077] S7. After the newly added longitudinal beams, lattice beams at the slope top and capping beams in step S6 are cured to reach 80% of the design strength, seal the anchor heads of the newly added anchor bolts or anchor cables constructed in step S2 to complete the construction of the slope top reinforcement structure system; Tension the aforementioned newly added anchor cables according to the design parameters and lock them, and pour concrete to seal the anchor heads.

[0078] S8. After the construction of the slope top reinforcement structure system is completed, construct the slope top road and ancillary structures.

[0079] Preferably, a monitoring plan is formulated before the project construction, and monitoring is carried out during the whole construction process and operation period to provide timely and dynamic feedback on the slope reinforcement effect, especially the displacement and settlement values of the pipe gallery at the slope top.

[0080] The present invention makes the most of the original designed slope support structure system, takes measures to lower the elevation and translate the position of the anchor bolts (cables) in the range affected by the excavation of the pipe gallery at the slope top, and reasonably adjusts the driving angle to improve the overall stability of the high-steep slope adjacent to the pipe gallery at the slope top and effectively control the slope top displacement. The slope top pipe trench backfilling of the present invention uses foamed concrete materials for layered backfilling, which can reduce the overall soil pressure of the slope and is integrally poured with the vertical micro steel pipe piles, increasing the anti-deformation strength of the concrete filling material and effectively reducing the post-construction settlement deformation of the slope top. The present invention utilizes the mechanism of controlling the slope top displacement by the modified micro steel pipe piles, can quickly and accurately estimate the slope top displacement value and review the design dimensions and specifications of the steel pipe piles, and effectively ensure that the slope top displacement is controlled within the design and specification ranges.

[0081] The present invention greatly improves the overall stability of a high-steep slope adjacent to a pipe gallery at the slope top, effectively controls the displacement of the pipe gallery adjacent to the slope top, effectively controls the settlement of the pipe gallery adjacent to the slope top within the design and specification range, and at the same time, the use of a foamed concrete structure to fill the pipe trench (groove) can reduce the filling pressure, ensure the compactness and strength. The present invention is applicable to the situation where the original slope support system fails to consider the newly planned municipal pipe gallery adjacent to the slope top due to serious lag in municipal planning, especially for the situation where the upper 1-2 rows of anchor rods (cables) need to be cancelled due to the conflict between the constructed original slope support system and the newly built municipal pipe gallery adjacent to the slope top. In order to ensure the permanent stability during the construction process and operation stage and the long-term safe operation of the pipe gallery, an economical, practical and convenient reinforcement system and construction method are proposed.

[0082] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the structural relationship and principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A high-steep slope reinforcement system with a sloping roof adjacent to a later-built municipal pipe gallery, comprising an original slope lattice anchor support structure constructed on the slope surface of the original slope (1) and a pipe gallery structure (5) constructed on the top of the original slope (1), wherein the pipe gallery structure (5) is adjacent to the slope surface of the original slope (1), and is characterized in that: The reinforcement system further includes an excavation and backfill structure (2) located on the side of the utility tunnel structure (5) adjacent to the slope surface of the original slope (1), a row of newly added anchor rods or cables (3) constructed below the first row of original anchor rods or cables (7) under the slope top of the original slope (1), and a row of micro steel pipe piles (6) constructed below the outer side of the slope surface adjacent to the utility tunnel structure (5) at the slope top of the original slope (1); the excavation and backfill structure (2) is a retaining structure formed by excavating and backfilling foamed concrete on the side of the utility tunnel structure (5) adjacent to the slope surface of the original slope (1), the driving angle of the newly added anchor rods or cables (3) is 30 - 35°, and the foundation or cushion of the utility tunnel structure (5) is avoided; the spacing of the micro steel pipe piles (6) is 1.0 - 2.0 m, and the pile top area thereof is buried in the excavation and backfill structure (2).

2. The high-steep slope reinforcement system for a municipal pipe gallery built adjacent to the rear of a gabled roof according to claim 1, wherein: The original slope lattice anchor support structure includes a reinforced concrete square lattice beam (4) formed by formwork pouring on the slope surface of the original slope (1) with slope excavation, and original anchor rods or cables (7) driven into the slope from the intersection of each longitudinal lattice beam and transverse lattice beam of the square lattice beam (4). A capping beam (8) is provided at the slope top of the original slope (1), and a bottom sealing beam (9) and a drainage structure (10) are provided at the slope bottom of the original slope (1). The capping beam (8) is close to the land use red line (12); the horizontal and vertical spacing of the original anchor rods or cables (7) is 2.0 - 3.5 m, and the driving angle is 20° - 25°; the newly added anchor rods or cables (3) replace the first row of original anchor rods or cables under the slope top of the original slope (1) that are removed. A newly added longitudinal beam (400) is provided on the vertical center line of each lattice frame of the first row of square lattice beams (4) under the slope top of the original slope (1), and the newly added anchor rods or cables (3) are driven into the slope from the center of each newly added longitudinal beam (400).

3. A high-steep slope reinforcement system for a municipal pipe gallery built adjacent to the rear of a gabled roof according to claim 1 or 2, characterized in that: The micro steel pipe piles (6) adopt grouted steel pipe piles. The steel pipe piles are arranged at equal intervals. The pile diameter of a single steel pipe pile is 110 - 300 mm, and slurry outlet holes with a diameter of 15 mm are arranged in a spiral pattern at equal intervals on the pipe wall. The axial spacing between adjacent two slurry outlet holes is 30 - 50 cm.

4. A high-steep slope reinforcement system for a municipal pipe gallery built adjacent to a gabled roof according to claim 1 or 2, characterized in that: The utility tunnel structure (5) includes a utility tunnel trench (500) and a utility tunnel main structure (501) buried in the utility tunnel trench (500). A crushed stone or concrete utility tunnel cushion (502) is provided at the bottom of the utility tunnel trench (500). The buried depth of the utility tunnel cushion (502) is 1.6 - 3.5 m. The utility tunnel main structure (501) is close to the land use red line (12) and adopts open cut foundation pit support. Soil and stone backfill layers (503) are formed by backfilling soil and stones on the inner side of the utility tunnel main structure (501) away from the slope surface, and the side of the utility tunnel main structure (501) adjacent to the slope surface is adjacent to the excavation and backfill structure (2).

5. A high-steep slope reinforcement system with a gabled roof adjacent to a newly built municipal pipe gallery behind, characterized in that: Both the original anchor rods or cables (7) and the newly added anchor rods or cables (3) adopt ordinary steel bar anchor rods, prestressed steel bar anchor rods or prestressed steel strand cables; the specifications of the newly added anchor rods or cables (3) are the same as those of the original anchor rods or cables (7), and the length of the newly added anchor rods or cables (3) is equal to or greater than the length of the original anchor rods or cables (7).

6. A construction method for a high-steep slope reinforcement system with a sloping roof adjacent to a newly built municipal pipe gallery later, characterized in that, The specific construction steps are as follows: S1. According to the design drawings of the municipal utility tunnel structure and its pipe trench, overlay the design plan position, elevation of the municipal utility tunnel structure and its pipe trench with the design drawing of the original slope lattice anchor support structure, and evaluate and confirm the scope of the existing slope top bolts or cables and lattice beams that are affected; and determine the reinforcement design plan based on the sectional view and elevation view after overlay; the reinforcement design includes setting a new longitudinal beam in the middle of each lattice frame above the first row of bolts or cables affected by the original slope lattice anchor support structure, setting new bolts or cables in the middle of each new longitudinal beam, and adding a row of vertical grouting steel pipe piles between the outside of the slope top utility tunnel structure and the capping beam. The pile diameter of each steel pipe pile is 110 - 300 mm, the spacing between adjacent two steel pipe piles is 1.0 - 2.0 m, and the pile length of each steel pipe pile embedded in the slope soil at the bottom of the pipe trench of the municipal utility tunnel structure is not less than 2 times the pile length above the bottom of the pipe trench; S2. According to the reinforcement design drawing drawn in step S1, construct a row of new bolts or cables at the designed position of the new bolts or cables. The driving angle of the new bolts or cables is 30 - 35°, and avoid the foundation or cushion of the municipal utility tunnel structure, and then remove the first row of bolts or cables affected by the original slope lattice anchor support structure; S3. Remove the slope top lattice beam and capping beam affected by the pipe trench excavation range, and then excavate the pipe trench from the ground according to the design drawings of the municipal utility tunnel structure and its pipe trench, carry out temporary support for the pipe trench, and successively carry out the construction of laying the cushion, pouring the foundation and the main body of the utility tunnel in the pipe trench to complete the overall construction of the utility tunnel structure; S4. Construct the new vertical grouting steel pipe piles, drill holes from the position between the outside of the constructed utility tunnel structure and the capping beam, drive in the steel pipe piles and grout. The construction of the vertical grouting steel pipe piles avoids the bolts or cables; S5. Carry out symmetric backfilling on both sides of the pipe trench. The backfilling material on the inner side far from the slope surface is soil mixed with stones, and on the outer side close to the slope surface, formwork is set up and foamed concrete is poured in layers, and both are densely backfilled to the ground; S6. After the foamed concrete structure is cured to reach 80% of the design strength, construct the new longitudinal beam, and construct the slope top lattice beam and capping beam removed in step S3, and restore the affected drain holes and greening; S7. After the new longitudinal beam, slope top lattice beam and capping beam constructed in step S6 are cured to reach 80% of the design strength, seal the new bolts or cables constructed in step S2 to complete the construction of the slope top reinforcement structure system; when the new bolts or cables are prestressed bolts or cables, tension the bolts or cables according to the design parameters and lock them, and then pour concrete for sealing; when the new bolts are ordinary steel bar bolts, directly pour concrete for sealing; S8. After the construction of the slope top reinforcement structure system is completed, construct the slope top road and ancillary structures.

7. The construction method of a high-steep slope reinforcement system with a gabled roof adjacent to a later-built municipal pipe gallery according to claim 6, characterized in that: When determining the reinforcement design plan in step S1, verify and determine the best construction parameters of the micro steel pipe piles according to the overall stability theory of the traditional slope lattice anchor support combined with the micro pile control slope top displacement theory. The specific steps are as follows: a. Set each construction parameter of the micro steel pipe piles according to the steel pipe pile specifications of engineering experience. The construction parameters of the micro steel pipe piles include the material, pile diameter and wall thickness of the steel pipe piles; b. Calculate the top displacement of the micro steel pipe pile group based on the above-set parameters, and compare the calculated top displacement of the micro steel pipe pile group with the maximum displacement of the slope top that meets the design and specifications. When it is less than the maximum displacement of the slope top in the design and specifications, the above parameters meet the construction requirements; The calculation process of the top displacement of the micro steel pipe pile group is as follows: Regard a single micro steel pipe pile as a flexural "cantilever beam", and first calculate the top displacement of a single micro steel pipe pile according to the following formula: I = π(D^4 - d^4) / 64 Where: σ—theoretical horizontal displacement at the top of a single micro steel pipe pile; q0—uniform soil pressure behind the pile; H—length above the anchorage section of the pile; E—elastic modulus of the micro steel pipe pile; I—moment of inertia of the micro steel pipe pile; D and d are the outer diameter and inner diameter of the steel pipe pile respectively; Where the values of E and I are fixed values after the material specifications of the steel pipe pile are determined; Then, calculate the top displacement of the micro steel pipe pile group according to the following formula: K—correction factor, K takes 1.1 - 1.

3.

8. The construction method of a high-steep slope reinforcement system with a gabled roof adjacent to a newly built municipal utility tunnel afterwards, as claimed in claim 6 or 7, is characterized in that: In the S1 step, the original slope lattice anchor support structure is constructed according to the slope ratio of the original slope design drawing, and the overall construction follows the principle of from top to bottom. The construction steps include in sequence: slope earth excavation, slope surface trimming, construction of drainage ditches and drainage holes, construction of anchor rods or cables, construction of lattice beams, tensioning, locking and grouting of prestressed anchor rods or cables, and slope surface grass planting and greening; the completed original slope lattice anchor support structure includes a reinforced concrete square frame beam and original anchor rods or cables driven into the slope from the intersection of the longitudinal and transverse lattice beams of the reinforced concrete square frame beam. There is a capping beam at the top of the original slope, and a bottom sealing beam and a drainage structure at the bottom of the original slope. The capping beam is close to the land use red line; the horizontal and vertical spacing of the original anchor rods or cables is 2.0 - 3.5m, and the driving angle is 20° - 25°.

9. The construction method of a high-steep slope reinforcement system with a gabled roof adjacent to a newly-built municipal pipe gallery behind, characterized in that: In the S2 step, the new anchor rods or cables replace the first row of anchor rods or cables affected by the removed original slope lattice anchor support structure, and the new anchor rods or cables are driven into the slope from the central part of each new longitudinal beam; the new anchor rods or cables have the same specifications as the first row of anchor rods or cables of the original slope lattice anchor support structure, and the length is equal to or greater than the length of the first row of anchor rods or cables of the original slope lattice anchor support structure.

10. The construction method of a high-steep slope reinforcement system with a gabled roof adjacent to a newly built municipal pipe gallery behind, characterized in that: In the S4 step, the vertical grouting steel pipe piles are arranged at equal intervals, and slurry outlet holes are arranged in a spiral pattern at equal intervals on the pipe wall of each steel pipe pile, with a hole diameter of 15mm and an axial spacing of 30 - 50cm.

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