Construction method suitable for replacing high-water-content soil layer in storage yard

Abstract

The invention discloses a construction method suitable for replacing a high-water-content soil layer in a storage yard, which comprises the following steps of: S1, determining the depth, the diameter and the spacing of a replacement body, and selecting a rammer with a corresponding size; s2, a drainage ditch is constructed around the to-be-replaced area; flattening the to-be-replaced area to a specified elevation; s3, the point tamping position is determined, and point tamping construction is conducted according to the depth, the diameter and the distance of the replacement body determined in the step S1; s4, the site is leveled, and overall common tamping construction is conducted in the to-be-replaced area; s5, carrying out vibration rolling construction by utilizing a vibratory roller, carrying out a load plate test on the rolled site, detecting the bearing capacity of the foundation, and if the detection result meets the design requirement, completing acceptance; and if the detection result does not meet the requirement, returning to the step S4. The water content in the soil layer can be reduced, the consolidation degree and the bearing capacity of the soil layer are improved, and the stability of a foundation is improved.

Description

Technical Field

[0001] The present invention relates to the field of foundation treatment construction, and more specifically, to a construction method suitable for replacing a soil layer with a high water content in a storage yard. Background Art

[0002] The storage yard is an important part of the port terminal, which has the function of temporary storage and transshipment of incoming and outgoing goods. The foundation of the storage yard is generally a soft soil foundation formed by land reclamation. Due to the low permeability of the soft soil foundation, the pore water pressure between the soil particles cannot be quickly dissipated, and large-scale dynamic compaction is usually used for foundation treatment. The soft soil layer formed by land reclamation is relatively thick. After being treated with the general dynamic compaction method, the upper part of the soil layer is in a consolidated state, while the deep part of the soil layer is still in a loose state, which does not meet the foundation bearing capacity requirements. In particular, there are soft soil layers and silty soils with high water content in the foundation of coastal storage yards, and the foundation treatment effect is difficult to show. In actual operation, the ordinary dynamic compaction method has limitations in the treatment of soil layers with high water content. There is abundant rainfall in southern my country, and rain is often encountered during the construction of the storage yard foundation treatment, resulting in poor dynamic compaction construction effect. The soil layer in the construction area needs to be dried to reduce the moisture before continuing the construction, which is easy to cause delays in the construction period. In addition, when the dynamic compaction method is used in construction, the rammer compacts the surface, and the compaction energy is transmitted downward step by step and gradually weakens, which can easily lead to the unconsolidated soft soil at the bottom and insufficient bearing capacity. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these purposes and other advantages according to the present invention, a construction method suitable for replacing a soil layer with high water content in a storage yard is provided, comprising the following steps: S1. Determine the depth, diameter and spacing of the displacement body and select a rammer of corresponding size; S2. Construct drainage ditches around the area to be replaced; level the area to be replaced to the specified elevation; S3, determine the spot tamping position, and perform spot tamping construction according to the replacement body depth, diameter and spacing determined in step S1; S4. Level the site and carry out overall tamping construction in the area to be replaced; S5. Perform vibration compaction construction using a vibratory roller, and conduct a load plate test on the site where compaction has been completed to detect the bearing capacity of the foundation. If the test results meet the design requirements, the acceptance is completed; if the test results do not meet the requirements, return to step S4.

[0005] Preferably, step S1 also includes construction preparation: combining on-site field exploration and geological survey data to determine the area to be replaced and the moisture content of the area to be replaced, and measuring the original landform elevation of the area to be replaced.

[0006] Preferably, step S1 specifically includes the following steps: S11, estimating the depth of the replacement body, the diameter and weight of the spot tamping hammer; and calculating the diameter and spacing of the replacement body according to the diameter of the spot tamping hammer; S12, estimating the single tamping energy and determining the number of tamping times; S13, calculating the estimated ground elevation amount according to the depth, diameter and single tamping energy of the displacement body and the estimated value, if the estimated ground elevation amount meets the design requirements, proceeding to step S14, otherwise returning to step S11, re-correcting the estimated values; S14, calculating the foundation deformation according to the depth, diameter and single tamping energy of the displacement body and the estimated value, if the foundation deformation meets the design requirements, proceed to step S15, otherwise return to step S11, and re-correct the estimated values; S15. Calculate the residual settlement of the foundation after strong compaction replacement based on the depth, diameter and single impact energy of the replacement body and the estimated value. If the residual settlement meets the design requirements, the estimated value of the current depth, diameter and spacing of the replacement body is the design value; otherwise, return to step S11 and re-revise the estimated values.

[0007] Preferably, in step S2, the width of the drainage ditch is greater than 30 cm and the depth is greater than 40 cm; after the construction of the drainage ditch is completed, the raised area in the area to be replaced is excavated to a specified elevation, and the areas with insufficient elevation are backfilled with soil; if silt is exposed after excavation, it is necessary to cover it with a layer of soil to form a construction working surface.

[0008] Preferably, in step S3, the tamping points are arranged in a square at a determined interval; and the replacement filler of the replacement body is crushed stone or block stone, and the maximum particle size does not exceed 600 mm.

[0009] Preferably, the point tamping construction in step S3 specifically includes the following steps: S31, re-measure the elevation of the site after leveling in step S2, mark the tamping points and number them; S32, arranging the replacement filler to the tamping point; S33, the tamping machine and the point tamping hammer are in place, the tamping hammer is aligned with the tamping point position, the elevation of the top surface of the hammer before tamping and the drop distance of the tamping hammer are measured, and the drop distance is locked; the tamping machine releases the point tamping hammer to tamp the replacement filler; after each tamping is completed, the replacement filler is filled; S34, repeat step S33 until the tamping reaches a predetermined elevation; S35, the tamping machine and the spot tamping hammer are moved to the next tamping point, and steps S32 to S34 are repeated until the spot tamping construction of the entire area to be replaced is completed.

[0010] Preferably, the overall tamping construction in step S4 specifically includes the following steps: S41, earthwork uplift caused by spot tamping in the leveling site; S42, measure the site elevation and lay out the general tamping baseline; S43, the tamping machine and the general tamping hammer are in place, the tamping hammer is aligned with the tamping point position, the elevation of the top surface of the hammer before tamping and the drop distance of the tamping hammer are measured, and the drop distance is locked; the tamping machine releases the point tamping hammer to tamp; each time the tamping is done, the site is leveled, and the elevation after leveling is measured; S44, the tamping machine and the general tamping hammer are moved to the next tamping point, and step S43 is continued until the general tamping construction of the entire area to be replaced is completed.

[0011] The present invention has at least the following beneficial effects: 1. The construction method for replacing soil layers with high water content in a storage yard provided by the present invention sets the depth, diameter and spacing of the replacement body that meet the requirements, then adopts the form of first spot tamping to construct a strong tamping replacement body, and then general tamping to treat the soft soil in layers, thereby reducing the water content in the soil layer, improving the consolidation degree and bearing capacity of the soil layer; it can also improve the ability of the soil body to resist vibration liquefaction and eliminate the soil's collapsibility, and increase the uniformity of the foundation; it is particularly suitable for high-water-content soft soil with a water content of more than 40% in the foundation filling material of the storage yard in water transport engineering.

[0012] 2. The construction method provided by the present invention is suitable for replacing soil layers with high water content in a storage yard. The replacement body formed has good water permeability, which is beneficial to the dissipation and consolidation of excess pore water pressure in the soil, and helps to further improve the stability and bearing capacity of the foundation.

[0013] 3. The construction method provided by the present invention is suitable for replacing the soil layer with high water content in the storage yard. The construction steps are simple, no additional building materials are required, the construction efficiency is high, and time and cost can be effectively saved.

[0014] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the construction method for replacing the soil layer with high water content in the storage yard according to the present invention; Figure 2 It is a schematic diagram of the arrangement of tamping points in the construction method for replacing the soil layer with high water content in the storage yard according to the present invention; Figure 3It is a schematic diagram of the arrangement of general tamping points in the construction method for replacing the soil layer with high water content in the storage yard according to the present invention; DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0017] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0018] like Figure 1 As shown, the present invention provides a construction method suitable for replacing a soil layer with a high water content in a storage yard, comprising the following steps: S1. Determine the depth, diameter and spacing of the displacement body and select a rammer of corresponding size; S2. Construct drainage ditches around the area to be replaced; level the area to be replaced to the specified elevation; S3, determine the spot tamping position, and perform spot tamping construction according to the replacement body depth, diameter and spacing determined in step S1; S4. Level the site and carry out overall tamping construction in the area to be replaced; S5. Perform vibration compaction construction using a vibratory roller, and conduct a load plate test on the site where compaction has been completed to detect the bearing capacity of the foundation. If the test results meet the design requirements, the acceptance is completed; if the test results do not meet the requirements, return to step S4.

[0019] In this technical solution, by setting the depth, diameter and spacing of the replacement body that meet the requirements, and then adopting the form of first spot tamping to construct the strong tamping replacement body and then general tamping, the soft soil is treated in layers, thereby reducing the water content in the soil layer, improving the consolidation degree and bearing capacity of the soil layer; it can also improve the soil's ability to resist vibration liquefaction and eliminate the soil's collapsibility, and increase the uniformity of the foundation; it is especially suitable for high-water-content soft soil with a water content of more than 40% in the foundation filling of the storage yard in water transport projects.

[0020] During construction, step S1 also includes construction preparation: combining on-site field exploration and geological survey data, determining the area to be replaced and the moisture content of the area to be replaced, and measuring the original landform elevation of the area to be replaced. Through on-site field exploration, visually combined with construction drawings, determine the area to be replaced as the area to be replaced; combined with geological survey data, the thickness of the soft soil layer and the approximate moisture content of the soil in the area are determined through the soil layer cross-section diagram of the nearest survey point; take part of the soft soil in the area for geotechnical testing to determine the moisture content; according to the control grid corner points, measure the original landform elevation of the site.

[0021] In step S1, the depth, diameter and spacing of the displacement body are determined, and a rammer of corresponding size is selected; the specific steps include: S11, estimating the depth of the replacement body, the diameter and weight of the spot tamping hammer; and calculating the diameter and spacing of the replacement body according to the diameter of the spot tamping hammer; The depth and diameter of the replacement body are determined by soil conditions and design requirements. It should penetrate the soft soil layer to reach the harder soil layer, and should not exceed the depth specified by the construction standards. Then select the corresponding rammer according to the design tamping energy and the specifications of the replacement body. The diameter of the replacement body is 1.1~1.2 times that of the point tamping rammer, and the spacing is not less than 2 times the diameter of the point tamping rammer. Taking a certain grocery yard as an example, considering the average load of 20kPa, the characteristic value of the shallow foundation bearing capacity is ≥150kpa, and the compaction degree is ≥95% when the soil layer thickness is between 0~80cm, and the compaction degree is ≥94% when the soil layer thickness is between 80~150cm. According to construction experience, the estimated depth of the replacement body is at least 8m. According to the tamping energy requirements on the construction drawings, the point tamping energy is 6000KJ and the general tamping energy is 1500KJ. The selected point tamping rammer is a cylinder with a diameter of 1.4-1.5m, and the general tamping rammer is a round cake with a bottom area of ​​4.0-5.0㎡. Estimates of the diameter and spacing of the displaced volumes are then calculated.

[0022] S12, estimating the single tamping energy and determining the number of tamping times; The single tamping energy can be determined according to factors such as the type of foundation soil and the depth of the replacement body, and can be estimated specifically according to the following empirical formula: (1) (2) In formula (1) and formula (2), H1 is the depth of the displacement body, is the average value of single impact energy, E W is the minimum value of single impact energy. The estimated value of single impact energy is and E W Choose between.

[0023] The number of tamping times should be determined according to the soil thickness, surface conditions and use requirements, and should meet the following requirements: the displacement body penetrates the soft soil layer, the cumulative tamping amount is 1.5~2.0 times the designed pier length, and the average tamping amount of the last two hits is not more than 50~100mm. The number of tamping times can also be determined based on on-site tamping tests.

[0024] S13, calculating the estimated ground elevation amount according to the depth, diameter and single tamping energy of the displacement body and the estimated value, if the estimated ground elevation amount meets the design requirements, proceeding to step S14, otherwise returning to step S11, re-correcting the estimated values; The moisture content, single tamping energy, diameter and depth of the displacement body and ground elevation under the same foundation soil category in the historical construction data are fitted to form an empirical formula, which is then brought into the estimated values ​​determined in steps S11 and S12 to calculate the estimated ground elevation. During actual construction, a test tamping plan can also be formulated based on the estimated values ​​determined in steps S11 and S12, and the estimated ground elevation can be determined through test tamping.

[0025] S14, calculating the foundation deformation according to the depth, diameter and single tamping energy of the displacement body and the estimated value, if the foundation deformation meets the design requirements, proceed to step S15, otherwise return to step S11, and re-correct the estimated values; The foundation deformation includes the displacement body deformation and the long-term deformation of the soft soil at the bottom of the displacement body. The displacement body deformation is determined by the static load test of equal area, and the long-term deformation of the soft soil at the bottom of the displacement body is calculated according to the diffusion angle theory. The specific calculation method can be the calculation method given in the "Technical Design Code for Building Foundations" GB5007.

[0026] S15, according to the depth, diameter and single tamping energy of the replacement body and the estimated value, calculate the residual settlement of the foundation after the strong tamping replacement. If the residual settlement meets the design requirements, the estimated values ​​of the depth, diameter and spacing of the current replacement body are the design values; otherwise, return to step S11 and re-correct the estimated values; The residual settlement can be obtained in the following ways: obtain the rheological parameters of the soil according to the experimental parameters conducted in the geological survey report, establish the rheological equation according to the selected three-element model (composed of elastic elements, plastic elements and viscous elements), and solve the rheological equation to obtain the variation law of foundation settlement over time in combination with the actual load and boundary conditions such as the depth and diameter of the displacement body and the estimated value. The variation law is the function curve of the settlement and time. According to the obtained variation law, determine the settlement S1 at a certain time t1 (such as completion), and as time continues to pass to t2, obtain the corresponding settlement S2, and the difference between S1 and S2 is the residual settlement.

[0027] In step S2, the width of the drainage ditch is greater than 30 cm and the depth is greater than 40 cm; after the construction of the drainage ditch is completed, the raised area in the area to be replaced is excavated to the specified elevation, and the areas with insufficient elevation are backfilled with soil; if silt is exposed after excavation, it is necessary to cover it with a layer of soil to form a construction working surface.

[0028] In step S3, Figure 2 As shown, the tamping points are arranged in a square at a certain interval; the replacement filler of the replacement body is crushed stone or block stone, and the maximum particle size does not exceed 600mm.

[0029] The spot tamping construction specifically includes the following steps: S31, re-measure the elevation of the site after leveling in step S2, mark the tamping points and number them; S32, arranging the replacement filler to the tamping point; S33, the tamping machine and the point tamping hammer are in place, the tamping hammer is aligned with the tamping point position, the elevation of the top surface of the hammer before tamping and the drop distance of the tamping hammer are measured, and the drop distance is locked; the tamping machine releases the point tamping hammer to tamp the replacement filler; after each tamping is completed, the replacement filler is filled; S34, repeat step S33 until the tamping reaches a predetermined elevation; S35, the tamping machine and the spot tamping hammer are moved to the next tamping point, and steps S32 to S34 are repeated until the spot tamping construction of the entire area to be replaced is completed.

[0030] The arrangement of the general tamping points in step S4 is as follows: Figure 3 As shown in the figure, the overlapped part of the tamping hammer shall not be less than 1 / 3 of the diameter of the tamping hammer; the overall tamping construction specifically includes the following steps: S41, earthwork uplift caused by spot tamping in the leveling site; S42, measure the site elevation and lay out the general tamping baseline; S43. Put the tamping machine and the general tamping hammer in place, align the tamping hammer with the tamping point, measure the top elevation of the hammer before tamping and the drop distance of the tamping hammer, and lock the drop distance; release the tamping hammer to tamp; level the site after each tamping, and measure the elevation after leveling; when the tamping hammer is tilted due to the inclination of the pit bottom, level the pit bottom in time. During the strong tamping construction, the groundwater level should be controlled at 1.5m below the tamping surface; S44, the tamping machine and the general tamping hammer are moved to the next tamping point, and step S43 is continued until the general tamping construction of the entire area to be replaced is completed.

[0031] In step S5, the use of a vibratory roller for vibratory compaction construction specifically includes: using a bulldozer to flatten the tamping pit, and then using a vibratory roller for vibratory compaction construction; vibrating and compacting 6 to 8 times, with the vibratory roller moving one round trip as one time, with the rolling overlap width not less than 30 cm, and adjacent rolling times are staggered in an orthogonal direction; the vibratory compaction area is divided into layers, with 30 cm within a 1 m depth range as one layer, and 1 m outside the 1 m depth range as one layer; until the construction site is compacted to the specified elevation.

[0032] Carry out load plate test on the site where rolling has been completed to test the bearing capacity of the foundation. If the test results meet the design requirements, the acceptance is completed; if the test results do not meet the requirements, it is necessary to re-carry out general tamping construction and vibration rolling construction, and re-test after the construction is completed.

[0033] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A construction method suitable for replacing soil layers with high water content in a storage yard, characterized in that: The following steps are involved: S1. Determine the depth, diameter and spacing of the displacement body and select a rammer of corresponding size; S2. Construct drainage ditches around the area to be replaced; level the area to be replaced to the specified elevation; S3, determine the spot tamping position, and perform spot tamping construction according to the replacement body depth, diameter and spacing determined in step S1; S4. Level the site and carry out overall tamping construction in the area to be replaced; S5. Perform vibration compaction construction using a vibratory roller, and conduct a load plate test on the site where compaction has been completed to detect the bearing capacity of the foundation. If the test results meet the design requirements, the acceptance is completed; if the test results do not meet the requirements, return to step S4.

2. The construction method for replacing a soil layer with a high water content in a storage yard as claimed in claim 1, characterized in that: Before step S1, construction preparation is also included: combining on-site field exploration and geological survey data, determining the area to be replaced and the moisture content of the area to be replaced, and measuring the original landform elevation of the area to be replaced.

3. The construction method for replacing a soil layer with high water content in a storage yard as claimed in claim 1, characterized in that: Step S1 specifically includes the following steps: S11, estimating the depth of the replacement body, the diameter and weight of the spot tamping hammer; and calculating the diameter and spacing of the replacement body according to the diameter of the spot tamping hammer; S12, estimating the single tamping energy and determining the number of tamping times; S13, calculating the estimated ground elevation amount according to the depth, diameter and single tamping energy of the displacement body and the estimated value, if the estimated ground elevation amount meets the design requirements, proceeding to step S14, otherwise returning to step S11, re-correcting the estimated values; S14, calculating the foundation deformation according to the depth, diameter and single tamping energy of the displacement body and the estimated value, if the foundation deformation meets the design requirements, proceed to step S15, otherwise return to step S11, and re-correct the estimated values; S15. Calculate the residual settlement of the foundation after strong compaction replacement based on the depth, diameter and single impact energy of the replacement body and the estimated value. If the residual settlement meets the design requirements, the estimated value of the current depth, diameter and spacing of the replacement body is the design value; otherwise, return to step S11 and re-revise the estimated values.

4. The construction method for replacing a soil layer with high water content in a storage yard as claimed in claim 1, characterized in that: In step S2, the width of the drainage ditch is greater than 30 cm and the depth is greater than 40 cm; after the construction of the drainage ditch is completed, the raised area in the area to be replaced is excavated to the specified elevation, and the areas with insufficient elevation are backfilled with soil; if silt is exposed after excavation, it is necessary to cover it with a layer of soil to form a construction working surface.

5. The construction method for replacing a soil layer with high water content in a storage yard as claimed in claim 1, characterized in that: In step S3, the tamping points are arranged in a square shape at a determined interval; the replacement filler of the replacement body is crushed stone or block stone, and the maximum particle size does not exceed 600 mm.

6. The construction method for replacing a soil layer with high water content in a storage yard as claimed in claim 5, characterized in that: The point tamping construction in step S3 specifically includes the following steps: S31, re-measure the elevation of the site after leveling in step S2, mark the tamping points and number them; S32, arranging the replacement filler to the tamping point; S33, the tamping machine and the point tamping hammer are in place, the tamping hammer is aligned with the tamping point position, the elevation of the top surface of the hammer before tamping and the drop distance of the tamping hammer are measured, and the drop distance is locked; the tamping machine releases the point tamping hammer to tamp the replacement filler; after each tamping is completed, the replacement filler is filled; S34, repeat step S33 until the tamping reaches a predetermined elevation; S35, the tamping machine and the spot tamping hammer are moved to the next tamping point, and steps S32 to S34 are repeated until the spot tamping construction of the entire area to be replaced is completed.

7. The construction method for replacing a soil layer with high water content in a storage yard as claimed in claim 1, characterized in that: The overall tamping construction in step S4 specifically includes the following steps: S41, earthwork uplift caused by spot tamping in the leveling site; S42, measure the site elevation and lay out the general tamping baseline; S43, the tamping machine and the general tamping hammer are in place, the tamping hammer is aligned with the tamping point position, the elevation of the top surface of the hammer before tamping and the drop distance of the tamping hammer are measured, and the drop distance is locked; the tamping machine releases the point tamping hammer to tamp; each time the tamping is done, the site is leveled, and the elevation after leveling is measured; S44, the tamping machine and the general tamping hammer are moved to the next tamping point, and step S43 is continued until the general tamping construction of the entire area to be replaced is completed.

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