Method for evaluating influence of new project construction on adjacent bridge

Abstract

The invention discloses a method for evaluating the influence of new project construction on an adjacent bridge. The method comprises the following steps: S1, investigating basic data; s2, performing current situation detection and current situation evaluation on the existing bridge; s3, determining an existing bridge deformation control standard and a bridge deformation monitoring control index value; s4, formulating a special construction scheme and a special protection measure; s5, performing pre-evaluation by adopting numerical simulation according to the special construction scheme and the special protection measure; s6, the result of the step S5 is judged, if the evaluation result meets the bridge deformation control standard, the step S7 is executed, and otherwise, the step S4 is executed; s7, according to the special construction scheme and the special protection measures formulated in the step S4, construction operation is carried out, and on-site monitoring is carried out; s8, the monitoring result in the step S7 is judged, if the monitoring result meets the bridge monitoring control index, the step S9 is executed, otherwise, the step S4 is executed again, and the stratum physical and mechanical parameters are adjusted according to the monitoring result; and S9, continuing construction operation and field monitoring until the construction is finished.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, and in particular to a method for evaluating the impact of new construction on adjacent bridges. Background Art

[0002] With the improvement of transportation infrastructure, there are more and more elevated bridges in cities. New construction projects sometimes inevitably have to cross and run parallel to existing bridge structures. The construction of new construction projects will cause disturbance of the surrounding soil, which in turn causes deformation and displacement of the surrounding strata, which may cause deformation and additional stress on the foundation of adjacent bridges. If the deformation or additional stress of the bridge foundation exceeds a certain level, it will affect the normal use of the bridge and even cause safety problems. In order to ensure that the construction of new construction projects can be carried out safely and orderly under the premise of protecting existing bridges, there is an urgent need for an assessment method for the impact of new construction construction on adjacent bridges, in order to ensure the safety of existing bridges. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method for evaluating the impact of new construction on adjacent bridges. The evaluation method is more systematic and complete than the traditional evaluation method, and can accurately reflect the impact of new construction on adjacent existing bridges. The evaluation method can not only ensure the feasibility of the construction plan, but also ensure the effectiveness of the reinforcement measures. At the same time, the construction plan and reinforcement measures can be optimized and improved according to the on-site monitoring results to ensure the safety of the existing bridge structure.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] A method for evaluating the impact of new construction on adjacent bridges, characterized in that it comprises the following steps:

[0006] S1. Investigate basic data related to existing bridges and new construction projects;

[0007] S2. Conduct status inspection and status assessment of existing bridges;

[0008] S3. Determine the existing bridge deformation control standards and bridge deformation monitoring control index values;

[0009] S4. Formulate special construction plans and special protection measures;

[0010] S5. Preliminary assessment is carried out using numerical simulation according to the special construction plan and special protection measures; the parameters of the numerical simulation are the physical and mechanical parameters of the formation, including cohesion c, internal friction angle φ, elastic modulus E, and bulk density γ;

[0011] S6. Determine the result of step S5. If the evaluation result meets the bridge deformation control standard, execute step S7; otherwise, return to execute step S4;

[0012] S7. Carry out construction work and conduct on-site monitoring according to the special construction plan and special protection measures formulated in step S4;

[0013] S8. Judge the monitoring result in step S7. If the monitoring result meets the bridge monitoring control index, execute step S9. Otherwise, return to execute step S4 and adjust the physical and mechanical parameters of the formation involved in step S5 according to the monitoring result.

[0014] S9. Continue construction work and on-site monitoring until construction is completed.

[0015] Furthermore, in step S1, the basic data include: 101) existing bridge data: design service life of the bridge, structural form, foundation burial depth, and pile foundation length; 102) new project data: scale of the new project, structural form of the new project, and construction method of the new project; 103) relative position relationship: horizontal position relationship and vertical position relationship between the new project and the existing bridge; 104) geological conditions: geological structure, stratum lithology, hydrogeology, and stratum physical and mechanical parameters.

[0016] Furthermore, in step S2, the current status detection of the bridge includes: crack status, damage status, concrete strength, concrete carbonization depth, steel bar stress and bearing capacity calculation of the main structure of the bridge.

[0017] Furthermore, in step S2, the current status assessment of the bridge includes: the bearing capacity status and the ability to resist additional deformation of the bridge.

[0018] Furthermore, in step S3, the existing bridge deformation control standard includes: pile foundation settlement control standard value, pile foundation horizontal deformation control standard value and pile foundation additional bending moment control standard value; the bridge deformation monitoring control index value is 75% of the bridge deformation control standard.

[0019] Furthermore, in step S4, the special protection measures include: 401) construction measures: adjusting the construction method, adjusting the construction steps, optimizing the excavation method and support means; 402) deformation control measures: nearby stratum improvement measures, construction impact isolation measures; 403) bridge structure strengthening measures: pile foundation reinforcement, pile foundation replacement, and structural reinforcement.

[0020] Furthermore, in step S5, the numerical simulation includes establishing an evaluation model in the software; the evaluation model includes an existing bridge structure model, a new construction structure model and special protection measures.

[0021] Furthermore, in step S6, the bridge deformation value in the numerical simulation is compared with the bridge deformation control standard; if the bridge deformation value in the numerical simulation is smaller than the bridge deformation control standard, step S7 is executed; if the bridge deformation value in the numerical simulation is larger than the bridge deformation control standard, step S4 is executed after modifying the construction method and protective measures.

[0022] Furthermore, in step S8, the bridge deformation value in the on-site monitoring of step S7 is compared with the bridge deformation monitoring control index value in step S3; if the bridge deformation value in the on-site monitoring is smaller than the bridge deformation monitoring control index value, step S9 is executed; if the bridge deformation value in the on-site monitoring is larger than the bridge deformation monitoring control index value, step S4 is executed, and the physical and mechanical parameters of the formation of the evaluation model are adjusted according to the monitoring results.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] 1. The evaluation method of the present invention comprehensively considers factors such as the service life of the bridge, cracks and damage of the existing structure, and clearly proposes deformation control standards and construction monitoring control indicators for existing bridges.

[0025] 2. Before construction, the evaluation method of the present invention preliminarily formulates a special construction plan and reinforcement measures according to the deformation control requirements of the bridge, compares and analyzes the numerical simulation results with the control values, optimizes and improves the construction plan and reinforcement measures, and guides the project construction.

[0026] 3. During the construction process, the evaluation method of the present invention combines the construction deformation monitoring data to correct the calculation parameters in the numerical simulation, so that the evaluation result is more accurate; the main factors causing bridge deformation are analyzed, and the construction plan and reinforcement measures are improved more specifically to ensure the safety of the existing bridge structure.

[0027] 4. The numerical simulation in the evaluation method of the present invention comprehensively considers the actual geological conditions, the current status of the bridge, the relative position relationship between the new project and the existing bridge, and analyzes the actual construction process and reinforcement measures of the new project, so that the calculation results are closer to the actual situation, providing a basis and basis for the optimization of the construction plan and reinforcement measures.

[0028] 5. The evaluation method of the present invention overcomes the technical problem that the traditional evaluation method only adopts qualitative evaluation and determines the size of risk based on engineering experience, but cannot quantitatively evaluate the impact of construction on existing bridges.

[0029] 6. In the evaluation method of the present invention, control indicators are first formulated, and then numerical simulation is used for pre-evaluation before construction. During the construction process, the construction plan is adjusted and optimized according to the on-site monitoring structure to ensure that the deformation value of the bridge is always controlled within the formulated control indicator range until the construction is completed. The evaluation of the present invention runs through the entire construction process, which improves the safety of engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of the evaluation method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] like Figure 1 As shown, this embodiment provides a method for evaluating the impact of new construction on adjacent bridges, which specifically includes the following steps:

[0033] Step 1. Survey of relevant basic data, including: 1) existing bridge data: structural form, foundation depth (d), pile length (L); 2) new construction data: new construction structure and construction method; 3) relative position relationship: horizontal position relationship and vertical position relationship between new construction and existing bridges; 4) geological conditions: water level depth (S) and physical and mechanical parameters of strata (cohesion c, internal friction angle φ, elastic modulus E, bulk density γ, etc.);

[0034] Step 2. Conduct current status inspection and current status assessment on existing bridges. The current status inspection of bridges includes: crack status, damage status, concrete strength, concrete carbonization depth, steel stress, etc. of the main structure of the bridge. According to the inspection results, the bridge bearing capacity reduction factor (ξ) is proposed, and the resistance effect value (Z) is calculated according to the current design specifications. The additional settlement value of the bridge pile foundation (ΔD), the additional horizontal deformation value of the pile foundation (ΔH) and the additional bending moment value of the pile foundation (ΔW) are proposed, so that γ0S(Δd, ΔH, ΔW)≤ξZ, where γ0 is the importance coefficient of the bridge structure and S(·) is the load effect function;

[0035] Step 3. Determine the existing bridge deformation control standard and bridge deformation monitoring control index. The existing bridge deformation control standard includes: pile foundation settlement control standard value (δd = 0.8Δd), pile foundation horizontal deformation control standard value (δh = 0.8ΔH) and pile foundation additional bending moment control standard value (δw = 0.8ΔW). The bridge deformation monitoring control index value is 75% of the bridge deformation control standard.

[0036] Step 4. Develop special construction plans and protection measures. Special protection measures include: 1) Construction measures: adjust construction methods, adjust construction sequence, optimize excavation methods and support methods; 2) Deformation control measures: nearby stratum improvement measures (soil reinforcement), construction impact isolation measures (setting isolation piles); 3) Bridge structure strengthening measures: pile foundation reinforcement, pile foundation replacement, and structural reinforcement.

[0037] Step 5. Preliminary evaluation is conducted by numerical simulation according to the special construction plan and protection measures. The numerical simulation includes establishing an evaluation model in the software according to the basic data investigated in step 1 (including the bridge structure form, foundation burial depth, pile foundation length; the new construction structure form; and the relative position relationship between the two); the evaluation model establishes the actual stratum conditions according to the physical and mechanical parameters of the stratum (cohesion c, internal friction angle φ, elastic modulus E, bulk density γ, etc.) in the basic data investigated in step 1, and establishes the construction steps according to the construction sequence and protection measures (deformation control measures, bridge structure strengthening measures) mentioned in step 4;

[0038] Step 6. Judge the results of step 5 (pile foundation settlement value (D), pile foundation horizontal deformation value (H) and pile foundation additional bending value (W)). If the evaluation result D<δd, H<δh and W<δw, execute step 7, otherwise return to execute step 4;

[0039] Step 7. Carry out construction work and conduct on-site monitoring according to the construction plan and protection measures formulated in step 4;

[0040] Step 8. Judge the monitoring results in step 7 (pile foundation settlement value (Dj), pile foundation horizontal deformation value (Hj) and pile foundation additional bending value (Wj). If the monitoring results Dj < 75% × δd, Hj < 75% × δh and Wj < 75% × δw, execute step 9. Otherwise, return to step 4 and adjust the physical and mechanical parameters of the formation in step 5 (cohesion c, internal friction angle φ, elastic modulus E, bulk density γ, etc.) according to the monitoring results.

[0041] Step 9. Continue construction work and on-site monitoring until construction is completed.

[0042] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A method for evaluating the impact of new construction on adjacent bridges, characterized in that: The following steps are involved: S1. Investigate basic data related to existing bridges and new construction projects; S2. Conduct status inspection and status assessment of existing bridges; S3. Determine the existing bridge deformation control standards and bridge deformation monitoring control index values; S4. Formulate special construction plans and special protection measures; S5. Preliminary evaluation is carried out using numerical simulation according to special construction plans and special protection measures; the physical and mechanical parameters of the formation in numerical simulation mainly include cohesion c, internal friction angle φ, elastic modulus E, and bulk density γ; S6. Determine the result of step S5. If the evaluation result meets the bridge deformation control standard, execute step S7; otherwise, return to execute step S4; S7. Carry out construction work and conduct on-site monitoring according to the special construction plan and special protection measures formulated in step S4; S8. Judge the monitoring result in step S7. If the monitoring result meets the bridge monitoring control index, execute step S9. Otherwise, return to execute step S4 and adjust the physical and mechanical parameters of the formation involved in step S5 according to the monitoring result. S9. Continue construction work and on-site monitoring until construction is completed.

2. The method for evaluating the impact of new construction on adjacent bridges according to claim 1, characterized in that: In step S1, the basic data include: 101) existing bridge data: bridge design service life, structural form, foundation burial depth, pile length; 102) new project data: new project scale, new project structural form and new project construction method; 103) relative position relationship: the horizontal position relationship and vertical position relationship between the new project and the existing bridge; 104) geological conditions: geological structure, stratum lithology, hydrogeology and stratum physical and mechanical parameters.

3. The method for evaluating the impact of new construction on adjacent bridges according to claim 1 is characterized in that: In step S2, the current status detection of the bridge includes: crack status, damage status, concrete strength, concrete carbonization depth, steel bar stress and bearing capacity calculation of the main structure of the bridge.

4. The method for evaluating the impact of new construction on adjacent bridges according to claim 1 is characterized in that: In step S2, the current status assessment of the bridge includes: the bearing capacity status and the ability to resist additional deformation of the bridge.

5. The method for evaluating the impact of new construction on adjacent bridges according to claim 1 is characterized in that: In step S3, the existing bridge deformation control standards include: pile foundation settlement control standard value, pile foundation horizontal deformation control standard value and pile foundation additional bending moment control standard value; the bridge deformation monitoring control index value is 75% of the bridge deformation control standard.

6. The method for evaluating the impact of new construction on adjacent bridges according to claim 1 is characterized in that: In step S4, the special protection measures include: 401) construction measures: adjusting the construction method, adjusting the construction steps, optimizing the excavation method and support means; 402) deformation control measures: nearby stratum improvement measures, construction impact isolation measures; 403) bridge structure strengthening measures: pile foundation reinforcement, pile foundation replacement, and structural reinforcement.

7. The method for evaluating the impact of new construction on adjacent bridges according to claim 1 is characterized in that: In step S5, the numerical simulation includes establishing an evaluation model in the software; the evaluation model includes an existing bridge structure model, a new construction structure model and special protection measures.

8. The method for evaluating the impact of new construction on adjacent bridges according to claim 1 is characterized in that: In step S6, the bridge deformation value in the numerical simulation is compared with the bridge deformation control standard; if the bridge deformation value in the numerical simulation is smaller than the bridge deformation control standard, step S7 is executed; if the bridge deformation value in the numerical simulation is larger than the bridge deformation control standard, the construction method and protection measures are modified and step S4 is executed.

9. The method for evaluating the impact of new construction on adjacent bridges according to claim 7, characterized in that: In step S8, compare the bridge deformation value in the on-site monitoring of step S7 with the bridge deformation monitoring control index value in step S3; if the bridge deformation value in the on-site monitoring is less than the bridge deformation monitoring control index value, execute step S9; if the bridge deformation value in the on-site monitoring is greater than the bridge deformation monitoring control index value, execute step S4, and adjust the physical and mechanical parameters of the formation of the evaluation model according to the monitoring results.

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