Coastal silt foundation offset surcharge counterpressure correction method

Abstract

This invention discloses a method for correcting foundation misalignment by surcharge counterpressure on coastal silty ground, comprising the following steps: S1, foundation data observation; S2, correction data analysis; S3, correction scheme design; S4, surcharge implementation; S5, repositioning confirmation; and S6, surrounding soil consolidation. This invention utilizes a proposed empirical formula for surcharge counterpressure, based on measured data and design parameters, to quantitatively calculate correction parameters, addressing the lack of precise basis in existing methods. Correction errors can be precisely controlled, avoiding reverse deviations. This correction method eliminates the need for complex calculations of internal silty stress; parameters can be determined solely through observation and drawing data. It is simple to operate, widely adaptable, and suitable for coastal silty geological construction sites that have completed detailed exploration and site preparation. It can be implemented concurrently with installation construction, shortening the critical path construction period. Combined with foundation settlement and misalignment data analysis software, it can quickly resolve foundation misalignment problems.

Description

Technical Field

[0001] This invention relates to the fields of municipal engineering and power engineering construction technology, and more specifically, to a method for correcting the offset of coastal silt foundations by surcharge counterpressure. Background Technology

[0002] The silty soil, widely distributed in coastal areas, is characterized by high water content, high compressibility, and low bearing capacity. Utilizing such areas for the construction of factories and municipal facilities can effectively save land resources and expand construction space, aligning with the trend of green development. However, the poor stability of silty soil means that construction disturbances such as foundation pit excavation and pile foundation work, as well as heavy-load disturbances such as heavy vehicle traffic and heavy object accumulation, can easily lead to internal imbalance of the silty soil, causing equipment foundations and structure foundations to shift towards the direction of lower compressive stress.

[0003] Existing methods for correcting foundation offset mainly include surcharge counterpressure, excavation unloading, and push-and-reset, all of which have obvious drawbacks: they can only perform qualitative construction, lack precise control basis and measures, cannot quantify correction parameters, and are prone to problems such as insufficient correction or reverse deviation; the core of the surcharge counterpressure method is to estimate the effect by calculating additional stress, but there is currently no unified standard formula, and it relies on the experience judgment of construction personnel, resulting in unstable correction quality, low construction efficiency, and may prolong the total construction period.

[0004] To address this, a quantitative correction scheme based on observation data is proposed to achieve the goals of precise control, shorten the construction period, and avoid secondary deviations. Summary of the Invention

[0005] The technical objective of this invention is to address the above-mentioned shortcomings by providing a method for correcting the offset of coastal silt foundations by surcharge counterpressure, thereby resolving the problems mentioned above.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The method for correcting the offset of coastal silt foundations by surcharge counterpressure includes the following steps: S1. Basic Data Observation: Before construction, engineering survey benchmarks are set up, and measurement points are established for the foundation centerline elevation and edge lines. Continuous observation is conducted throughout the construction process and before handover, recording foundation horizontal displacement and settlement data, and determining the cumulative offset time. ; S2. Correction Data Analysis: When the foundation displacement exceeds the standard deviation, calculate the foundation offset per unit weight per unit time and set the expected return time. and the back pressure offset per unit weight per unit time; S3. Correction scheme design: Determine the counter-pressure load and quantity, delineate the load area, clarify the observation method and frequency, and design foundation fixing measures after repositioning. S4. Loading Implementation: Lay counterweight loads according to the plan, implement construction safety measures simultaneously, and monitor foundation position changes in real time. S5. Reset Confirmation: When the longitudinal and transverse center lines, horizontal center lines, main edge lines and elevations of the foundation all meet the design requirements, the correction and reset are confirmed to be successful. S6. Consolidation of surrounding soil: Replace and compact the soil layer within 3m depth; mix the soil layer below 3m with a consolidating agent for consolidation.

[0007] Preferably, in step S1, the observation tools used are a total station, a level, or a theodolite, with an observation frequency of once every 1-4 hours, and the cumulative offset time... The duration from the initial offset to the start of correction.

[0008] Preferably, in step S3, the back pressure load P is determined using an empirical formula for back pressure, and the empirical formula is: ; in, This is the distance adjustment factor. , This is the horizontal distance between the center of gravity of the slab and the center of gravity of the foundation. The vertical distance between the center of gravity of the slab load and the center of gravity of the foundation. This is the adjustment coefficient for the counter-pressure load, and , Based on the quality of the foundation and installed equipment, The area of ​​the base subjected to silt compression. The projected area of ​​the counter-pressure reactor load.

[0009] Preferably, the counter-pressure load adjustment coefficient Values ​​are determined based on the severity of silt compression: For mild compression... During moderate compression During severe compression .

[0010] Preferably, the counterweight in step S3 is a concrete counterweight block, the loading area is set according to the foundation offset direction, and the horizontal distance between the center of gravity of the load and the center of gravity of the foundation is... Vertical distance is 2-5m. It is 1-3m.

[0011] Preferably, if the expected loading effect is not good in step S3, an unloading trench with a depth of 0.8-1.5m and a width of 0.5-1.0m is excavated on the side of the foundation that is under pressure.

[0012] Preferably, the loading in step S4 is carried out in a layered laying method, with each layer having a laying height of ≤0.5m. After laying, the layer is left to stand for 2-4 hours before laying the next layer.

[0013] Preferably, the criteria for successful reset in step S5 are: the offset of the longitudinal and transverse center lines of the foundation is ≤5mm, the elevation deviation of the horizontal center line is ≤3mm, and the position of the main edge lines meets the requirements of the design drawings.

[0014] Preferably, the solidifying agent for the soil layer below 3m in step S6 is composed of cement and nanoparticles with a particle size of 500nm. Nanoparticles with a diameter of 400nm Polyvinyl alcohol fiber is composed of 6 parts by weight: 3: 2: 0.2, forming a stable soil layer structure.

[0015] Preferably, in step S6, the soil layer within a depth of 3m is filled with graded sand and gravel, and after filling, it is compacted in layers with a compaction coefficient ≥0.95.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. This invention, through the proposed empirical formula for surcharge back pressure, is constructed based on measured data and design parameters, realizing the quantitative calculation of correction parameters, solving the problem of the lack of accurate basis in existing methods, and enabling precise control of correction error to avoid reverse deviation; 2. This invention eliminates the need for complex internal stress calculations in silt through a correction method. Parameters can be determined solely through observational data and drawing data. It is simple to operate, widely adaptable, and suitable for coastal silt geological construction sites that have completed detailed exploration and site preparation. 3. This invention can be carried out in parallel with installation and construction, shortening the critical path construction period. When used with foundation settlement and offset data analysis software system, it can quickly solve foundation offset problems. 4. This invention, combined with the surrounding soil consolidation process, fundamentally improves the geological stability of silt, prevents the foundation from shifting again later, and enhances the long-term reliability of the project. 5. This invention ensures safe and reliable construction quality and is groundbreaking in the precise control of foundation installation quality. It can be widely applied to the construction of equipment foundations and structure foundations for municipal engineering and power engineering to correct deviations. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the correction method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the stacking counterweight structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the excavation and unloading trench layout according to an embodiment of the present invention. Detailed Implementation

[0019] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 like Figures 1-3 As shown, the method for correcting offset of coastal silt foundation by surcharge counterpressure according to an embodiment of the present invention includes the following steps: S1. Basic Data Observation: Before construction, engineering survey benchmarks are set up, and measurement points are established for the foundation centerline elevation and edge lines. Continuous observation is conducted throughout the construction process and before handover. The observation tools used are a total station (angle accuracy ±2″), a level (accuracy ±0.5mm / km), and a theodolite (angle accuracy ±1″). The observation frequency is once every 1-4 hours (based on the characteristic that the daily average settlement rate of silt is ≥2mm, to ensure the capture of real-time offset data and avoid missing key changes). The horizontal displacement and settlement data of the foundation are recorded, and the cumulative offset time is determined. ; S2. Correction Data Analysis: When the foundation displacement exceeds the standard deviation (±10mm as specified in the Construction Quality Acceptance Standard for Building Foundation Engineering GB50202-2018), calculate the foundation offset per unit weight per unit time (Calculation formula: Offset ÷ ( × Set the expected shift time. And the back pressure offset per unit weight per unit time (not less than 1.2 times the calculated value to ensure the back pressure effect). S3. Correction scheme design: Determine the counterweight (concrete counterweights are preferred; alternatives include sandbags and steel ingots; the load density must be ≥18kN / m³). 3The quantity and location of the load area should be determined according to the direction of foundation offset (the minimum distance between the load area and the foundation edge should be ≥1m, the shape should preferably be rectangular, and the length-to-width ratio should be consistent with the length-to-width ratio of the foundation's compression surface to ensure uniform pressure transmission). The observation method and frequency should be specified, and the foundation fixing measures after repositioning should be designed (using steel plate anchors to connect with the foundation's pre-embedded steel plates, with anchor spacing ≤1.5m and anchoring depth ≥0.8m to prevent rebound after repositioning). If the expected load effect is not good (judgment criteria: the load calculated according to the formula exceeds the on-site bearing capacity limit or the load space is insufficient), an unloading trench with a depth of 0.8-1.5m and a width of 0.5-1.0m should be excavated on the compression side of the foundation (the distance between the trench and the foundation edge should be ≥0.5m to avoid disturbing the foundation). S4. Loading Implementation: Lay the counterweight load according to the plan, with each layer ≤0.5m in height. After laying, let it stand for 2-4 hours (based on the characteristics of silt consolidation time to avoid excessive local settlement due to excessive loading). Simultaneously implement construction safety measures (set up safety barriers and settlement monitoring and early warning devices), maintain the frequency of observation, and monitor the changes in the foundation position in real time. S5. Reset Confirmation: Observe the longitudinal and transverse center lines, horizontal center lines, main edge lines and elevations of the foundation. The criteria for successful reset are: the offset of the longitudinal and transverse center lines ≤ 5mm, the elevation deviation of the horizontal center line ≤ 3mm, the position of the main edge lines meets the requirements of the design drawings, and the data are stable for 3 consecutive observations (with an interval of 2 hours). The correction and reset are confirmed to be successful. S6. Surrounding Soil Consolidation: For soil layers within 3m depth, remove silt and replace with graded sand and gravel, compacting in layers (compaction coefficient ≥ 0.95, according to the requirements of the Technical Specification for Foundation Treatment of Buildings JGJ79-2012); for soil layers below 3m depth, use a mixing head to mix the solidifying agent into the soil layer. The solidifying agent consists of cement and nanoparticles with a particle size of 500nm. Nanoparticles with a diameter of 400nm Polyvinyl alcohol fiber is composed of a weight ratio of 6:3:2:0.2. Mechanism of action: nanotechnology. Filling the pores of silt, nano Polyvinyl alcohol fiber enhances the crack resistance of the cured layer, effectively improving the unconfined compressive strength of the cured silt compared to ordinary curing materials, thus forming a stable soil structure.

[0022] Example 2 The method for correcting the offset of coastal silt foundations by surcharge counterpressure provided in this embodiment differs from that in Embodiment 1 in that: For construction sites with relatively uniform and indistinct coastal silt geological distribution, an empirical formula for foundation offset and surcharge counterpressure is derived through linear regression analysis based on measured data (including foundation offset, silt parameters, and surcharge parameters): ; in, This refers to the counter-pressure reactor load, expressed in kg. This is the distance adjustment factor. , This is the horizontal distance between the center of gravity of the slab and the center of gravity of the foundation. This is the vertical distance between the center of gravity of the surcharge and the center of gravity of the foundation. The value is determined based on the principle of moment balance to ensure that the reaction force of the surcharge is effectively transmitted to the foundation. This is the adjustment coefficient for the counter-pressure load, and The values ​​were determined based on a comparative experiment conducted with three groups of silt with different moisture contents (35%, 45%, and 60%). This can help avoid insufficient correction, including mild compression. Moderate compression Severe compression ; Mass of the foundation and installed equipment, in kg (data from design drawings). The cumulative offset time is expressed in days (based on observation data; the starting point is determined by a baseline horizontal offset ≥ 2 mm). The area of ​​the base subjected to silt compression is expressed in meters. 2 (Data taken from design drawings; calculation method: projected value of the side surface area in contact with the silt of the foundation). The expected relocation time is in days (taken from construction planning data; it is recommended to take a value of 1 / 3 to 1 / 2 of the cumulative offset time to balance efficiency and safety). The projected area of ​​the counter-pressure reactor load is expressed in meters. 2 (Taken from construction planning data).

[0023] In summary, this method for correcting foundation misalignment by surcharge counterpressure in coastal silty soil areas, through data observation throughout the construction process, summarizes the key variables affecting the foundation due to geological conditions, constructs an accurate empirical formula for surcharge counterpressure, and forms a systematic correction method. This method enables quantitative control of foundation misalignment, improves the quality and efficiency of correction, and is applicable to the precise correction of equipment and structure foundation misalignment caused by construction disturbances and heavy load disturbances in coastal silty soil areas. It is particularly suitable for construction sites where detailed exploration and site preparation have been completed, and the silty soil distribution is basically uniform with no significant differences.

[0024] Through the above specific embodiments, those skilled in the art can easily implement the present invention. However, it should be understood that the present invention is not limited to the specific embodiments described above. Based on the disclosed embodiments, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions.

Claims

1. A method for correcting offset of coastal silt foundations by surcharge counterpressure, characterized in that, Includes the following steps: S1. Basic Data Observation: Before construction, engineering survey benchmarks are set up, and measurement points are established for the foundation centerline elevation and edge lines. Continuous observation is conducted throughout the construction process and before handover, recording foundation horizontal displacement and settlement data, and determining the cumulative offset time. ; S2. Correction Data Analysis: When the foundation displacement exceeds the standard deviation, calculate the foundation offset per unit weight per unit time and set the expected return time. and the back pressure offset per unit weight per unit time; S3. Correction scheme design: Determine the counter-pressure load and quantity, delineate the load area, clarify the observation method and frequency, and design foundation fixing measures after repositioning. S4. Loading Implementation: Lay counterweight loads according to the plan, implement construction safety measures simultaneously, and monitor foundation position changes in real time. S5. Reset Confirmation: When the longitudinal and transverse center lines, horizontal center lines, main edge lines and elevations of the foundation all meet the design requirements, the correction and reset are confirmed to be successful. S6. Consolidation of surrounding soil: Replace and compact the soil layer within 3m depth; mix and solidify the soil layer below 3m depth with a solidifying agent. In step S1, the observation tools used are a total station, a level, and a theodolite, with observations conducted every 1-4 hours, accumulating the offset time. The duration from the initial offset to the start of correction; In step S3, the back pressure load P is determined using an empirical formula for back pressure surcharge. The empirical formula is: ;in, This is the distance adjustment factor. , This is the horizontal distance between the center of gravity of the slab and the center of gravity of the foundation. The vertical distance between the center of gravity of the slab and the center of gravity of the foundation. This is the adjustment coefficient for the counter-pressure load, and , Based on the quality of the foundation and installed equipment, The area of ​​the base subjected to silt compression. The projected area of ​​the counter-pressure reactor load.

2. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to claim 1, characterized in that: The counter-pressure load adjustment coefficient Values ​​are determined based on the severity of silt compression: For mild compression... During moderate compression During severe compression .

3. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to claim 2, characterized in that: In step S3, the counterweight is a concrete counterweight block, the loading area is set according to the foundation offset direction, and the horizontal distance between the center of gravity of the load and the center of gravity of the foundation is... Vertical distance is 2-5m. It is 1-3m.

4. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to claim 3, characterized in that: If the expected loading effect is not good in step S3, an unloading trench with a depth of 0.8-1.5m and a width of 0.5-1.0m is excavated on the side of the foundation that is under pressure.

5. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to claim 4, characterized in that: In step S4, the surcharge is implemented using a layered laying method, with each layer having a height of ≤0.5m. After laying, the layer is left to stand for 2-4 hours before laying the next layer.

6. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to claim 5, characterized in that: The criteria for successful reset in step S5 are: the offset of the longitudinal and transverse center lines of the foundation is ≤5mm, the elevation deviation of the horizontal center line is ≤3mm, and the position of the main edge lines meets the requirements of the design drawings.

7. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to claim 6, characterized in that: In step S6, the solidifying agent for the soil layer below 3m consists of cement and nanoparticles with a particle size of 500nm. Nanoparticles with a diameter of 400nm Polyvinyl alcohol fiber is composed of 6 parts by weight: 3: 2: 0.2, forming a stable soil layer structure.

8. The method for correcting offset of coastal silt foundation by surcharge counterpressure according to any one of claims 1-7, characterized in that: In step S6, the soil layer within a depth of 3m is replaced with graded sand and gravel, and after replacement, it is compacted in layers with a compaction coefficient ≥0.95.

Images