Construction method of full-pile casing cast-in-place pile

Abstract

The invention discloses a construction method of a full-pile casing cast-in-place pile. The invention provides a method for simulating the influence of a newly-built infrastructure structure on an adjacent operation subway / railway, and the method comprises the following steps: S1, carrying out the field investigation and survey through combining with the surrounding environment, and arranging related parameters; s2, analyzing a position relation between a newly-built infrastructure structure and an adjacent operation subway / railway; s3, establishing a three-dimensional model to simulate dynamic construction of a newly-built infrastructure and a subway / railway structure, and performing safety evaluation; s4, performing risk analysis on the influence of external operation on the subway / railway; s5, combining the data and the influence analysis result, and carrying out construction; according to the full-pile casing cast-in-place pile construction method, by building the model and simulating the influence on the subway or the railway caused by newly-built infrastructures close to the subway or the railway, on one hand, the optimal construction method is found, the influence on the subway or the railway is avoided as much as possible, and on the other hand, the situation that the newly-built infrastructures cause faults of the subway or the railway is avoided; the normal use is influenced.

Description

Technical Field

[0001] The invention belongs to the technical field of cast-in-place piles, and in particular relates to a construction method of a full-casing cast-in-place pile. Background Art

[0002] As the artery of urban development, the transportation network between cities is of great importance to cities. Subways and railways occupying the main transportation network are particularly important. However, with the gradual development of the transportation network, subways / railways and infrastructure projects often appear in parallel or cross-construction during construction. When new infrastructure projects are near subway or railway construction, they will inevitably affect the safety and use of the existing subway structure.

[0004] At present, the domestic construction methods for such situations only involve monitoring, reinforcement and other fields, and lack a complete set of construction methods in the subway / railway affected areas. Summary of the invention

[0005] The object of the present invention is to provide a method for simulating the impact of a newly built infrastructure structure on an adjacent operating subway / railway, comprising the following steps:

[0006] Step S1, conduct on-site investigation in combination with the surrounding environment and sort out relevant parameters;

[0007] Step S2: Analyze the relationship between the newly built infrastructure structure and the adjacent operating subway / railway location;

[0008] Step S3, establishing a three-dimensional model to simulate the dynamic construction of new infrastructure and subway / railway structures, and conducting safety evaluation;

[0009] Step S4: risk analysis of the impact of external operations on subways / railways;

[0010] Step S5: Perform construction based on the data and the results of the impact analysis.

[0011] Furthermore, the step S1, conducts on-site investigation in combination with the surrounding environment, and sorts out relevant parameters mainly including relevant parameters of the new project and the subway / railway, namely: the number of pile foundations within the subway protection zone, the closest distance to the subway structure, the number of pedestals within the subway protection zone, the closest distance to the subway structure, the number of retaining walls within the subway protection zone, and the closest distance to the edge of the subway structure.

[0012] Furthermore, the step S2, analysis of the relationship between the newly built infrastructure structure and the adjacent operating subway / railway location is specifically: by connecting with the operating subway unit, obtaining relevant drawings of the subway / railway unit, checking with the construction drawings of the newly built infrastructure, and conducting actual on-site re-measurement at the same time, to determine the location relationship and impact range of the newly built projects and the operating subway / railway.

[0013] Furthermore, the specific process of step S3, establishing a three-dimensional model to simulate the dynamic construction of new infrastructure and subway / railway structures and conducting safety evaluation is:

[0014] Step S301, establishing a model, that is, establishing a stratum-structure model;

[0015] Step S302, parameter simulation, input the collected parameters into the established model, use Midas GTS NX to perform three-dimensional calculations, and select one or more of the following analyses according to construction requirements: static analysis, dynamic analysis, seepage analysis, stress-seepage coupling analysis, consolidation analysis, construction stage analysis, and slope stability analysis;

[0016] Step S303: confirm whether the construction meets the subway / railway safety requirements based on the three-dimensional calculation results.

[0017] Furthermore, the specific process of step S4, risk analysis of the impact of external operations on subways / railways is:

[0018] Step S401, establishing a model, that is, establishing a stratum-structure model;

[0019] Step S402, parameter simulation, input the collected parameters into the established model, use Midas GTS NX for three-dimensional calculation, and select one or more of static analysis, dynamic analysis, seepage analysis, stress-seepage coupling analysis, consolidation analysis, construction stage analysis, and slope stability analysis according to construction requirements.

[0020] The advantages of the present invention are as follows: the present invention provides a full-casing casing cast-in-place pile construction method, which simulates the impact of newly built infrastructure near a subway or railway on the subway or railway by establishing a model, and on the one hand finds the optimal construction method to avoid the impact on the subway or railway as much as possible, and on the other hand avoids the newly built infrastructure from causing failures near the subway or railway to affect normal use; the simulation method of the impact of the newly built infrastructure structure on the adjacent operating subway / railway is used to simulate the newly built infrastructure near the subway or railway, and summarizes the construction requirements and construction methods for avoiding the impact on the adjacent subway or railway.

[0021] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of risk analysis of subway / railway structures by external operations.

[0023] Figure 2 It is a flow chart of the external work construction method.

[0024] Figure 3 It is a schematic diagram of the overall three-dimensional calculation model.

[0025] Figure 4 It is a schematic diagram of the relationship model between the newly built bored piles and the subway. DETAILED DESCRIPTION

[0026] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the specific implementation methods, structural features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "aligned", "overlap", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0030] Example 1

[0031] This embodiment provides Figure 1 to Figure 4 A simulation method for the impact of a new infrastructure structure on an adjacent operating subway / railway is shown, comprising the following steps:

[0032] Step S1, conduct on-site investigation in combination with the surrounding environment and sort out relevant parameters;

[0033] Step S2: Analyze the relationship between the newly built infrastructure structure and the adjacent operating subway / railway location;

[0034] Step S3, establishing a three-dimensional model to simulate the dynamic construction of new infrastructure and subway / railway structures, and conducting safety evaluation;

[0035] Step S4: risk analysis of the impact of external operations on subways / railways;

[0036] Step S5: Perform construction based on the data and the results of the impact analysis.

[0037] Furthermore, the step S1, conducts on-site investigation in combination with the surrounding environment, and sorts out relevant parameters mainly including relevant parameters of the new project and the subway / railway, namely: the number of pile foundations within the subway protection zone, the closest distance to the subway structure, the number of pedestals within the subway protection zone, the closest distance to the subway structure, the number of retaining walls within the subway protection zone, and the closest distance to the edge of the subway structure.

[0038] Furthermore, the step S2, analysis of the relationship between the newly built infrastructure structure and the adjacent operating subway / railway location is specifically: by connecting with the operating subway unit, obtaining relevant drawings of the subway / railway unit, checking with the construction drawings of the newly built infrastructure, and conducting actual on-site re-measurement at the same time, to determine the location relationship and impact range of the newly built projects and the operating subway / railway.

[0039] Furthermore, the specific process of step S3, establishing a three-dimensional model to simulate the dynamic construction of new infrastructure and subway / railway structures and conducting safety evaluation is:

[0040] Step S301, establishing a model, that is, establishing a stratum-structure model;

[0041] Step S302, parameter simulation, input the collected parameters into the established model, use Midas GTS NX to perform three-dimensional calculations, and select one or more of the following analyses according to construction requirements: static analysis, dynamic analysis, seepage analysis, stress-seepage coupling analysis, consolidation analysis, construction stage analysis, and slope stability analysis;

[0042] Step S303: confirm whether the construction meets the subway / railway safety requirements based on the three-dimensional calculation results.

[0043] Furthermore, the specific process of step S4, risk analysis of the impact of external operations on subways / railways is:

[0044] Step S401, establishing a model, that is, establishing a stratum-structure model;

[0045] Step S402, parameter simulation, input the collected parameters into the established model, use Midas GTS NX for three-dimensional calculation, and select one or more of static analysis, dynamic analysis, seepage analysis, stress-seepage coupling analysis, consolidation analysis, construction stage analysis, and slope stability analysis according to construction requirements.

[0046] The simulation method of the impact of the new infrastructure structure on the adjacent operating subway / railway is used to simulate the new infrastructure near the subway or railway, and the following construction requirements are summarized to avoid the impact on the adjacent subway or railway:

[0047] 1) The absolute settlement of the subway structure is less than 10mm, and the absolute horizontal displacement is less than 10mm (including the final displacement of various loading and unloading);

[0048] 2) Differential settlement of subway structure < 0.04%Li (Li is the distance between two monitoring points);

[0049] 3) The width of structural cracks on the water-facing surface is less than 0.2mm, and on the water-receiving surface is less than 0.3mm (the width control value of shield segment cracks is 0.2mm), and there are no internal and external through cracks and concrete peeling;

[0050] 4) Differential settlement of deformation joints is less than 4mm;

[0051] 5) The additional load on the outer wall of the subway tunnel caused by construction is ≤20kPa.

[0052] The simulation method of the impact of the new infrastructure structure on the adjacent operating subway / railway is used to simulate the new infrastructure near the subway or railway, and the following construction methods are summarized to avoid the impact on the adjacent subway or railway:

[0053] 1) Close-range cast-in-place pile construction: close to the subway / railway, mud leakage may occur; there may be a risk of hole collapse, causing additional deformation of the subway structure. The full casing follow-up method is adopted to prevent mud leakage; hydraulic static pile driving machinery is used in steel casing construction to reduce disturbance to the subway structure and its surrounding rock.

[0054] 2) Construction of deep foundation pit near subway: During the excavation and backfilling process of deep foundation pit near subway, measures are mainly taken in terms of machinery use, load distribution, backfilling technology, etc. to solve the problem of negative friction resistance of subway bridge piles caused by ground compression and settlement deformation, which leads to additional deformation.

[0055] 3) Part of the flange support system of the cast-in-place box girder construction area is above the subway structure: the finite element software is used to build a model to simulate the dynamic construction process of the bridge project. The construction of the bridge superstructure is simulated, the deformation development process of the subway structure during the construction process is analyzed, and the maximum deformation, increment and total deformation of the tunnel structure during the construction of this project are determined, so as to analyze the adverse effects of bridge construction on the deformation of the subway structure.

[0056] 4) Transportation and hoisting of steel box girders near the subway: Through the early deployment simulation of the box girder hoisting process, the crawler crane and the beam transporter are positioned relative to the subway structure, and the load application area is adjusted not to be directly above the subway structure. The most unfavorable area during the steel box girder hoisting process is selected for safety calculation to ensure the safety of the subway structure.

[0057] 5) Protection construction of existing pipelines: Before the formal construction of the project, an on-site investigation will be carried out based on the underground pipeline map provided by the owner, and the location of the pipelines will be checked in detail. The pipelines that intersect with the project will be protected and relocated to ensure that the pipelines will not be damaged during the construction process and will not affect the subway structure.

[0058] The simulation method of the impact of the new infrastructure structure on the adjacent operating subway / railway is used to simulate the new infrastructure near the subway or railway, and the following key points of external construction are summarized:

[0059] 1. Construction monitoring

[0060] 1) The monitoring method adopts on-site inspection and instrument monitoring. The monitoring objects are divided into internal and external. The internal refers to the monitoring objects of the urban rail transit structure, and the external refers to the monitoring objects in the external operation impact area except the urban rail transit structure. For internal monitoring, automatic monitoring equipment is installed, and early warning values ​​are set to conduct comprehensive, real-time and automatic monitoring. For external monitoring, the whole construction process is monitored, including construction equipment operation monitoring, surrounding structure monitoring, etc.

[0061] 2) In order to ensure the accuracy of monitoring data, cross-checking is carried out by three parties (construction unit entrusts a third-party monitoring unit, construction unit entrusts a third-party monitoring unit, subway operating unit monitoring unit, and construction unit process monitoring).

[0062] 3) Monitoring construction must be started one week before the construction of bridge piles. The initial measurement results must be repeated for no less than 4 times. When the repeated observation results are basically consistent, the average value of the repeated observations is taken as the initial reading. Monitoring can be stopped until the external impact construction is completed and the deformation of the subway structure is observed to be stable; if the subway structure monitoring data is abnormal and the deformation is unstable, it is necessary to negotiate and communicate with the relevant departments of the subway company to develop a solution to ensure the safety of the subway structure.

[0063] 4) During the stages of bridge pile foundation, foundation pit excavation, box girder construction, and steel box girder hoisting, the operating subway structure data is monitored to provide feedback on the impact of the new project structure construction on the subway structure. At the same time, each set of data is monitored to reflect whether the construction process meets the requirements. If not, timely measures are taken to adjust the construction method to ensure the safety of the subway structure.

[0064] 2. Temporary construction layout

[0065] 1) Construction access roads on site: According to the location of the operating subway and the relative location of the new construction project, the construction access roads should be set up away from the construction area of ​​the subway structure to reduce disturbance directly above the subway structure;

[0066] 2) The main construction machinery is heavy machinery (excavators, concrete pump trucks, truck cranes, crawler cranes and other related machinery), and concrete hardened construction access roads are used to reduce disturbance to the subway structure.

[0067] 3) No overloading is allowed on top of the operating subway and temporary facilities must be set up.

[0068] 3. Bridge pile foundation

[0069] 1) Data joint measurement: Before the pile foundation construction, the pile position is measured jointly with the subway unit. The pile foundation construction can be carried out only after the review and confirmation, so as to avoid deviations and serious engineering accidents caused by drilling through the subway structure;

[0070] (2) Pile hole drilling: The full casing follow-up method is used to prevent mud leakage; hydraulic static pile driving machinery (full rotary drilling rig) is used for steel casing construction to reduce disturbance to the subway structure and its surrounding rock; the full steel casing can be followed to a position one times the hole diameter below the tunnel bottom;

[0071] 3) For the same foundation, first construct the pile foundation in the area far away from the subway to determine the various construction parameters, and then carry out the pile foundation construction close to the subway to ensure construction safety and ensure that the pile foundation construction does not affect the safe operation of the subway.

[0072] 4) Pile head breaking: During the pile head breaking process, static breaking is used to avoid excessive vibration being transmitted to the subway structure.

[0073] 4. Foundation pit construction

[0074] 1) The excavation and backfilling of the foundation pit shall be carried out strictly in accordance with the principles of "layering, block division, symmetry, balance and time limit";

[0075] 2) The excavation layer height shall not exceed 1.0m. Manual excavation shall be adopted within 1m of the subway structure, and the layered backfill height shall not exceed 0.5m.

[0076] 3) For excavation, use a moderately powered XCMG XE225DK excavator and limit frequent movement of the excavator during operation to avoid large ground vibrations caused by the excavator.

[0077] 4) It is strictly prohibited to pile up the excavated earth. It must be transported as it is excavated and disposed of outside the subway protection zone.

[0078] 5) During the backfilling process of the foundation pit, manual labor and small flat rammers are used to carry out backfill compaction operations. The backfill is carried out in layers, and each layer is controlled within 15 cm. It is strictly forbidden to turn on the vibration mode during the process to avoid disturbing the subway structure.

[0079] 6) Before construction, the boundary contour of the subway tunnel structure should be projected onto the ground and marked in conjunction with the subway unit. It is strictly prohibited to pile loads directly above the subway tunnel on the construction site, and it is strictly prohibited to move construction machinery at will. All machinery must operate according to the prescribed routes to avoid overloading.

[0080] 5. Cast-in-place box girder

[0081] 1) The cast-in-place box girder frame adopts a new type of disc-type support frame with light weight and high strength, and appropriately reduces the support spacing to effectively reduce the additional surface load;

[0082] 2) Before construction, together with the property right unit, the boundary contour line of the subway tunnel structure shall be projected onto the ground and marked. The soil of the frame foundation within 5m of the subway structure shall be unloaded first. After unloading the 0.8m thick soil, the gray soil and concrete frame foundation shall be processed (XCMG XD83VT double steel wheel roller (self-weight 8.3T) shall be used in the gray soil compaction process, and the thickness of each layer shall be less than 15cm) to ensure that the frame foundation construction within 5m of the subway structure does not generate additional load on the subway structure;

[0083] 3) Based on empirical calculations and the most unfavorable factors, the uniformly distributed load on the subway structure caused by the deadweight of the cast-in-place box girder and frame of this project is less than 20kpa, which meets the safety requirements.

[0084] 4) When pouring the support concrete for the cast-in-place box girder, carry out monitoring and measurement.

[0085] 5) The pouring of box girder concrete should strictly follow the principle of longitudinal and transverse layered pouring. The longitudinal pouring sequence is: first pour the middle span box girder and then pour the side span box girder, and pour in layers obliquely from the middle of the span to the top of the pier on both sides. The 3m range on both sides of the pier top is poured symmetrically from both sides to the center of the pier. When the middle span is poured to 3m above the pier top, pour a section every 1.5 to 2 hours and gradually close to the pier top. At this time, the two side spans are mainly poured to meet the requirements of symmetrical pouring on both sides of the pier top between the side span and the middle span. The transverse pouring sequence: On the curve, there is super height on the outside. In order to avoid squeezing the inner side of the formwork and biasing the support due to its fluidity during concrete pouring, each layer of concrete is poured in the order of outside first and inside later to ensure the stability of the buckle frame.

[0086] 6. Steel box girder construction

[0087] 1) During the simulation of box girder hoisting in the early stage, the crawler crane and the girder transporter were positioned relative to the subway structure, and the load application area was adjusted not directly above the subway structure;

[0088] 2) Select the most unfavorable area during the steel box girder hoisting process for safety calculation;

[0089] According to the design form of the pier and the arrangement of the support points, the stress analysis and overall stability verification of the temporary pier are carried out. The buried depth of the station structure top plate is 3.97 meters. According to the stress diffusion law, the stress diffusion angle is calculated as 23°, and the stress area increases to = (3 + (3.97 × tan23°) × 2)2 = 40.53m2. The increased load on the station structure top plate is = 1.2σ = 1.2 (40.7 + 10) × 9.8 ÷ 40.53 = 18.686KPa, which is less than the 20KPa control standard required by the specification and meets the specification requirements.

[0090] 3) Carry out stress analysis and overall stability verification on temporary piers according to the design form of piers and the arrangement of fulcrums; divide steel box girders into sections and arrange piers to avoid subway station entrances and exits and wind pavilion structures, so as to prevent direct loads on subway structures during the installation of piers and steel box girders.

[0091] In summary, the present invention provides a full-casing casing cast-in-place pile construction method. The full-casing casing cast-in-place pile construction method establishes a model to simulate the impact of new infrastructure near a subway or railway on the subway or railway. On the one hand, the optimal construction method is found to avoid the impact on the subway or railway as much as possible, and on the other hand, the new infrastructure is prevented from causing malfunctions near the subway or railway and affecting normal use.

[0092] Example 2

[0093] The EPC general contracting project of the municipal project of Fengming Road (formerly Kunming Road West Extension) Elevated Section (Afang Palace Toll Station-Fengdong Boundary) in Fengdong New City, Xixian New District, Shaanxi Province starts from the Afang Palace Toll Station of the New Xibao Expressway in the west and ends at the West Third Ring Shiqiao Interchange in the east. The total length of the bridge is 3.4km, with a total of 35 sections, including the main line viaduct (M line, MKY line), the Lianhuo auxiliary road connection bridge (MN, MS), and the Kunzuo and Kunyou ramp bridges (SU, ND). The bridge structure is cast-in-place prestressed concrete box girder + steel box girder. The project includes bridges, roads, pipelines, lighting, traffic safety and other projects. According to the design drawings and the relative position of the operating subway, the viaduct project is partially located within the 50m protection zone of the subway. The number of pile foundations involved in the subway protection zone is 311, the number of caps is 56, and the box girders are 15. The closest distance between the pile foundation and the subway structure is 3.21m.

[0094] The simulation method of the impact of the new infrastructure structure on the nearby operating subway / railway was used to simulate before construction, and scientific measures and methods were adopted for different stages of bridge construction to minimize the impact on the operating subway structure, ensure the normal operation of the subway, and not affect the normal progress of the new project. According to monitoring data, the impact of the project construction on the operating subway is within the allowable value range.

[0095] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for simulating the impact of a new infrastructure structure on an adjacent operating subway / railway, characterized in that: The steps include: Step S1, conduct on-site investigation in combination with the surrounding environment and sort out relevant parameters; Step S2: Analyze the relationship between the newly built infrastructure structure and the adjacent operating subway / railway location; Step S3, establishing a three-dimensional model to simulate the dynamic construction of new infrastructure and subway / railway structures, and conducting safety evaluation; Step S4: risk analysis of the impact of external operations on subways / railways; Step S5: Perform construction based on the data and the results of the impact analysis.

2. A method for simulating the impact of a newly built infrastructure structure on an adjacent operating subway / railway as claimed in claim 1, characterized in that: The step S1, conducting on-site investigation in combination with the surrounding environment, sorting out relevant parameters mainly includes relevant parameters of the new project and the subway / railway, namely: the number of pile foundations within the subway protection zone, the closest distance to the subway structure, the number of pedestals within the subway protection zone, the closest distance to the subway structure, the number of retaining walls within the subway protection zone, and the closest distance to the subway structure edge line.

3. A method for simulating the impact of a newly built infrastructure structure on an adjacent operating subway / railway as claimed in claim 1, characterized in that: The step S2, analysis of the relationship between the newly built infrastructure structure and the adjacent operating subway / railway location is specifically: by connecting with the operating subway unit, obtaining the relevant drawings of the subway / railway unit, checking with the construction drawings of the newly built infrastructure, and conducting actual on-site re-measurement to determine the location relationship between the newly built projects and the operating subway / railway, as well as the impact range.

4. A method for simulating the impact of a newly built infrastructure structure on an adjacent operating subway / railway as claimed in claim 1, characterized in that: The specific process of step S3, establishing a three-dimensional model to simulate the dynamic construction of new infrastructure and subway / railway structures and conducting safety evaluation is: Step S301, establishing a model, that is, establishing a stratum-structure model; Step S302, parameter simulation, input the collected parameters into the established model, use Midas GTS NX to perform three-dimensional calculations, and select one or more of the following analyses according to construction requirements: static analysis, dynamic analysis, seepage analysis, stress-seepage coupling analysis, consolidation analysis, construction stage analysis, and slope stability analysis; Step S303: confirm whether the construction meets the subway / railway safety requirements based on the three-dimensional calculation results.

5. A method for simulating the impact of a newly built infrastructure structure on an adjacent operating subway / railway as claimed in claim 4, characterized in that: Step S4: The specific process of risk analysis of the impact of external operations on subways / railways is: Step S401, establishing a model, that is, establishing a stratum-structure model; Step S402, parameter simulation, input the collected parameters into the established model, use Midas GTS NX for three-dimensional calculation, and select one or more of static analysis, dynamic analysis, seepage analysis, stress-seepage coupling analysis, consolidation analysis, construction stage analysis, and slope stability analysis according to construction requirements.

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