A foundation construction method based on the strong compaction method in red clay area and cement improved soil

Abstract

The present invention relates to a foundation construction method based on the strong tamping method and cement improved soil in red clay area, comprising the following steps: S1, cushion layer strong tamping method construction, selecting cushion layer strong tamping method construction, determining the tamping energy, tamping hammer specifications and lifting wire rope requirements, and tamping construction, and finally filling the tamping pit; S2, cement improved soil construction preparation, leveling the lower bearing layer and compacting, preparing the plain soil and performing water content determination and cement admixture determination; S3, plain soil paving and cement spreading, in a horizontal layered filling manner. The present invention combines the advantages of the cushion layer strong tamping method and cement improved soil to treat the method of the runway foundation of a general airport, which not only improves the bearing capacity of the foundation soil, reduces the deformation of the foundation, but also significantly improves the stability and safety of the foundation in the collapsible loess area during the construction process and the aircraft take-off and landing process. At the same time, it reduces the construction difficulty and cost, and can effectively reduce the harm caused by the collapsibility of loess, thereby ensuring the quality of the project after construction.

Description

Technical Field

[0001] The invention relates to the technical field of foundation construction, and in particular to a foundation construction method based on a red clay area dynamic tamping method and cement improved soil. Background Art

[0002] Since general airports in my country are widely distributed, covering a variety of geographical environments and soil conditions, especially in collapsible loess areas, the collapsible nature of loess and the complex engineering conditions of filling the airport foundation make the construction difficult. For the construction in thick collapsible loess areas, traditional methods such as replacement cushion method and dynamic tamping method are often difficult to deal with effectively, and the treatment depth is relatively shallow, the engineering volume is large, and it is not suitable for construction in thick collapsible loess areas. In addition, these traditional methods also have certain difficulties in ensuring the quality of the project, and the cost is also high. Therefore, it is necessary to choose a suitable construction method to effectively ensure the post-construction quality.

[0003] To solve the above problems, the present invention provides a foundation construction method based on the dynamic compaction method in red clay areas and cement improved soil, aiming to improve the stability and safety of the foundation in collapsible loess areas during construction and during aircraft take-off and landing. Summary of the invention

[0004] In view of the above problems existing in the prior art, the main purpose of the present invention is to provide a foundation construction method based on the red clay area dynamic compaction method and cement improved soil.

[0005] The technical solution of the present invention is as follows: a foundation construction method based on the red clay area dynamic tamping method and cement improved soil, comprising the following steps;

[0006] S1. Construction of cushion layer by dynamic compaction method: Select the cushion layer by dynamic compaction method, determine the compaction energy, compaction hammer specifications and lifting wire rope requirements, determine the construction technical parameters in the test area, carry out compaction construction, and finally fill the compaction pit;

[0007] S2. Preparation for cement-improved soil construction: determine the parameters for cement and plain soil, level the underlying layer and compact it, and after laying out the lines to determine the thickness and position, prepare the plain soil and perform water content and cement admixture measurements;

[0008] S3, spreading of raw soil and cement, spreading raw soil on the underlying layer in a horizontal layered filling manner, spreading cement and mixing with a road mixer to ensure uniformity and mixing quality;

[0009] S4, rolling and leveling, use a roller for preliminary rolling, then use a grader and manual methods for fine leveling and repairing, and finally use a heavy roller for compaction to ensure that the foundation surface is flat and uniform;

[0010] S5. Testing and quality control: use the sand filling method to test the density of the improved soil, conduct quality inspection on the compacted foundation, and record and compare the compaction thickness, number of times and test results;

[0011] S6. Maintenance and subsequent treatment: carry out maintenance work on cement soil to prevent freezing, monitor the rolling process and make necessary optimizations, and finally make final confirmation to ensure that the construction quality meets the requirements.

[0012] As a preferred implementation, step S1 can be refined as follows:

[0013] S11. Confirmation of design requirements: confirm the cushion treatment depth, tamping energy and tamping hammer specifications, as well as the requirements for the lifting wire rope of the dynamic tamping machine;

[0014] S12. Determine the test area: select the test area and conduct test tamping to select the construction technical parameters;

[0015] S13, tamping point layout: clean and level the site and lay a gravel cushion layer, and mark the first tamping point position;

[0016] S14. Selection of lifting wire rope: Select appropriate lifting wire rope according to the weight of the rammer and the safety factor;

[0017] S15, Ramming construction: put the ramming hammer in place, ram according to regulations and carry out relevant elevation measurements;

[0018] S16. Compacting is completed: Use a bulldozer to fill the compacting pit and conduct the final elevation measurement.

[0019] As a preferred implementation, step S2 can be refined as follows:

[0020] S21. Parameter determination: Determine the usage parameters of cement and soil to ensure that the design requirements are met;

[0021] S22, leveling of the lower bearing layer: Use a grader to level and compact the lower bearing layer;

[0022] S23, measurement and setting out: use the total station to determine the pile position, and set out the lines to mark the control points and the thickness and width positions;

[0023] S24, Raw soil preparation: clean the site and lay a gravel cushion layer to prepare raw soil;

[0024] S25, moisture content determination: Determine the moisture content of the raw soil and determine the loose paving thickness coefficient;

[0025] S26. Cement admixture determination: Determine the actual cement spreading area and cement admixture amount, and conduct cement admixture testing.

[0026] As a preferred implementation, step S3 can be refined as follows:

[0027] S31, Material laying and paving: According to the design requirements, the soil is spread on the underlying layer, using the horizontal layered filling method, and particles and debris are removed;

[0028] S32, Cement spreading: Use cement spreading vehicle to spread evenly, strictly control the spreading amount and related parameters;

[0029] S33, Mixing: Use a road mixer to mix the soil and cement to ensure uniformity and color;

[0030] S34, cement content test: test whether the cement content in cement mixed soil is qualified;

[0031] S35. Confirmation of mixing depth: Confirm the mixing depth to ensure that cement and soil are evenly mixed.

[0032] As a preferred implementation, step S4 can be refined as follows:

[0033] S41. Preliminary rolling: Use a roller to perform preliminary compaction to ensure that the surface of the cement-improved soil is flat;

[0034] S42, surface leveling: Use a land leveler and manual methods to perform fine leveling and repair local pits and uneven areas;

[0035] S43, Rolling and compaction: Use heavy rollers to roll at the specified compaction density, paying attention to speed, lap length and overlap width;

[0036] S44, rolling quality inspection: Conduct quality inspection after rolling to ensure there are no obvious wheel marks and uneven compaction;

[0037] S45. Filling of insufficient soil: As needed, fill the soil manually after rolling and level the ground again.

[0038] As a preferred implementation, step S5 can be refined as follows:

[0039] S51. Post-compaction inspection: Use the sand filling method to inspect the density of the improved soil to ensure that it meets the design requirements;

[0040] S52. Check quality: Check the quality of the compacted foundation, including surface flatness and uniformity;

[0041] S53. Record and compare: record the rolling thickness, number of passes and test results, and compare them with the design requirements;

[0042] S54, Improvement and treatment: Repair and reinforce the sections that do not meet the requirements;

[0043] S55. Final confirmation: The last test confirms that the compaction degree meets the design requirements and ensures the quality of the foundation.

[0044] As a preferred implementation, step S6 can be refined as follows:

[0045] S61. Post-rolling maintenance: perform maintenance work on the cement soil, keep it moist and avoid freezing;

[0046] S62. Antifreeze measures: Take appropriate antifreeze measures during winter construction to ensure construction quality;

[0047] S63. Optimization of rolling method: Use appropriate rolling method to avoid excessive damage to the improved soil structure;

[0048] S64. Monitor the rolling process: monitor the rolling speed and make necessary adjustments to ensure uniformity;

[0049] S65. Final confirmation: Carry out final inspection and confirmation to ensure that the foundation construction meets the requirements.

[0050] As a preferred implementation, in order to ensure the construction quality of step S1 and steps S2-S6, precise construction parameter control must be adopted, and high-precision measuring equipment and information management systems are required to accurately control material usage, tamping energy, admixture uniformity and thickness setting, including but not limited to real-time monitoring of soil moisture, compaction and deformation, and timely adjustment of parameters during the construction process.

[0051] As a preferred embodiment, before the cushion layer compaction method of step S1 is used, underground obstacles and mud-sinking red clay of different thicknesses are identified through geological exploration and ground scanning technology, so as to carry out comprehensive pretreatment of the construction area. This technical feature ensures comprehensive improvement from the deep foundation to the surface layer, and reduces the uncertainty and variability that may cause construction quality risks.

[0052] As a preferred embodiment, step S6 introduces maintenance and strengthening measures to ensure the strength and durability of cement-improved soil, which includes traditional moist maintenance and temperature control, as well as additional reinforcement of the foundation using new epoxy resin coatings, fiber reinforcement and other technologies. These measures can improve the foundation's anti-freeze and anti-penetration properties, enhance its bearing capacity and extend its life.

[0053] Compared with the prior art, the advantages and positive effects of the present invention are:

[0054] The method of treating the foundation of a general airport runway by combining the advantages of the cushion layer dynamic compaction method and cement improved soil not only improves the bearing capacity of the foundation soil and reduces foundation deformation, but also significantly improves the stability and safety of the foundation in the collapsible loess area during the construction process and during the take-off and landing of the aircraft. At the same time, the construction difficulty and cost are reduced, and the harm caused by the collapsibility of the loess can be effectively reduced, thereby ensuring the quality of the project after construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a cross-sectional view of the foundation treatment of the present invention;

[0056] Figure 2 It is the plan layout diagram of the tamping points of the present invention;

[0057] Figure 3 It is a schematic diagram of the overall process of the present invention;

[0058] Figure 4 This is a detailed flow chart of step S1 in the present invention;

[0059] Figure 5 Detailed flow chart of step S2 in the present invention;

[0060] Figure 6 This is a detailed flow chart of step S3 in the present invention;

[0061] Figure 7 This is a detailed schematic diagram of the S4 step in the present invention;

[0062] Figure 8 This is a detailed flow chart of step S5 in the present invention;

[0063] Fig. 9 It is a detailed schematic diagram of the S6 step in the present invention. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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.

[0065] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Example

[0066] like Figure 1-Figure 4 As shown, the present invention provides a foundation construction method based on the red clay area dynamic tamping method and cement improved soil, comprising the following steps:

[0067] S1. Construction of cushion layer by dynamic compaction method: Select the cushion layer by dynamic compaction method, determine the compaction energy, compaction hammer specifications and lifting wire rope requirements, determine the construction technical parameters in the test area, carry out compaction construction, and finally fill the compaction pit;

[0068] S11. Confirmation of design requirements: confirm the cushion treatment depth, tamping energy and tamping hammer specifications, as well as the requirements for the lifting wire rope of the dynamic tamping machine;

[0069] S12. Determine the test area: select the test area and conduct test tamping to select the construction technical parameters;

[0070] S13, tamping point layout: clean and level the site and lay a gravel cushion layer, and mark the first tamping point position;

[0071] S14. Selection of lifting wire rope: Select appropriate lifting wire rope according to the weight of the rammer and the safety factor;

[0072] S15, Ramming construction: put the ramming hammer in place, ram according to regulations and carry out relevant elevation measurements;

[0073] S16. Compacting is completed: Use a bulldozer to fill the compacting pit and conduct the final elevation measurement.

[0074] In this step:

[0075] Construction of cushion layer by dynamic tamping method: Dynamic tamping can be used as a means of karst detection during construction. The treatment depth is required to be no less than 5m. Two times of 2000KN.m spot tamping and one time of 1000KN.m full tamping are used. Considering the high water content of the clay layer, the cushion layer thickness is temporarily set at 1.0m. Before the dynamic tamping construction, a test area (20m×20m) is selected, and the construction technical parameters are selected through trial tamping:

[0076] Requirements for strong compaction and drop distance: The 2000kN.m strong compaction area point compaction hammer is planned to use 15 tons, the design requires the compaction energy to be 2000kN.m, and the drop distance H=13.33m;

[0077] The full tamping hammer of 2000kN.m strong tamping area is planned to use 15 tons, the design requires tamping energy of 1000kN·m, and the drop distance H=6.67m;

[0078] Requirements for lifting wire ropes for rammers of compaction machines: Based on the weight of the planned rammers, consider the safety factor during lifting, calculate the minimum breaking force of the lifting wire rope during the operation of the compaction machine, and then select the wire rope scheme. For example, a rammer weighing 15 tons is planned to be used in the compaction area, and a 35W*K7 wire rope (minimum breaking force 630KN) is selected as the wire rope. The verification process is as follows:

[0079] The load of the wire rope during the tamping process is: wire rope load = total weight of the tamping hammer = 15t

[0080] The minimum breaking force of the wire rope is =630KN=630000N

[0081] Actual on-site lifting safety factor = 630000N / (20t*9800N)=3.21;

[0082] The construction process of the foundation cushion layer dynamic compaction method is: clean and level the site, lay the gravel cushion layer → mark the first tamping point position, measure the site elevation → put the crane in place and aim the tamping hammer at the service point → measure the elevation of the hammer top before tamping → lift the tamping hammer to the predetermined height, unhook and let it fall freely, measure the elevation of the hammer top → run back and forth, complete the tamping of one tamping point according to the specified number of tamping times and control standards → repeat the above steps to complete the first tamping of all tamping points → fill the tamping pit with a bulldozer, measure the site elevation → after the specified interval, complete all tamping times according to the above procedure → use low-energy full tamping to compact the loose soil on the surface of the site, and measure the site elevation after tamping.

[0083] S2. Preparation for cement-improved soil construction: determine the parameters for cement and plain soil, level the underlying layer and compact it, and after laying out the lines to determine the thickness and position, prepare the plain soil and perform water content and cement admixture measurements;

[0084] S21. Parameter determination: Determine the usage parameters of cement and soil to ensure that the design requirements are met;

[0085] S22, leveling of the lower bearing layer: Use a grader to level and compact the lower bearing layer;

[0086] S23, measurement and setting out: use the total station to determine the pile position, and set out the lines to mark the control points and the thickness and width positions;

[0087] S24, Raw soil preparation: clean the site and lay a gravel cushion layer to prepare raw soil;

[0088] S25, moisture content determination: Determine the moisture content of the raw soil and determine the loose paving thickness coefficient;

[0089] S26. Cement admixture determination: Determine the actual cement spreading area and cement admixture amount, and conduct cement admixture testing.

[0090] In this step:

[0091] The required materials are as follows:

[0092] Cement: strength grade is P.C32.5 ordinary cement. After testing, the cement physical properties of fineness, setting time, stability and strength are all qualified;

[0093] Raw soil: The soil source comes from the soil taking location in the excavation area of ​​the site;

[0094] Water: drinking water or other water sources that meet the requirements;

[0095] S3, spreading of raw soil and cement, spreading raw soil on the underlying layer in a horizontal layered filling manner, spreading cement and mixing with a road mixer to ensure uniformity and mixing quality;

[0096] S31, Material laying and paving: According to the design requirements, the soil is spread on the underlying layer, using the horizontal layered filling method, and particles and debris are removed;

[0097] S32, Cement spreading: Use cement spreading vehicle to spread evenly, strictly control the spreading amount and related parameters;

[0098] S33, Mixing: Use a road mixer to mix the soil and cement to ensure uniformity and color;

[0099] S34, cement content test: test whether the cement content in cement mixed soil is qualified;

[0100] S35. Confirmation of mixing depth: Confirm the mixing depth to ensure that cement and soil are evenly mixed.

[0101] In this step:

[0102] Acceptance of sub-base leveling: Before filling, the sub-base is leveled with a grader and rolled with a roller to the design compaction standard. If the sub-base is too dry, water should be sprinkled appropriately to make the surface moist before paving;

[0103] Survey and lay out: Use a total station to encrypt and re-measure the pile position coordinates, set the middle pile every 20m, measure and set the roadbed filling control side piles and insert the filling layer control poles at the side piles, use red paint to mark the paving thickness and width of each layer, and hang the line for construction. Note that the overfill width on both sides of the roadbed slope should be 30 to 50cm;

[0104] Soil paving: Since each truckload of soil is about 21 cubic meters, through on-site construction improvement, the soil elevation measurement data shows that the virtual paving thickness of this work site is 33.8cm. Therefore, it is concluded that an 8m×8m grid should be laid in the lower bearing layer before filling. After the unloading of soil is completed, the bulldozer is used for initial leveling and paving is evenly spread. The grader is then leveled and the roller is used for static compaction. The compaction thickness is 30.2cm. The actual measured value of the loose paving thickness coefficient for calculating the thickness of the loose paving layer and the compacted layer is 1.119;

[0105] Moisture content determination: Determine the moisture content of the initially leveled loose soil, because the moisture content is the most important factor affecting the compaction coefficient of cement-improved soil filling, which can be obtained from the filler compaction curve;

[0106] Confirmation of actual cement spreading on site: After measuring the loose spreading coefficient of the raw soil at the site, which is 1.1, according to the formula: cement dosage (50kg) = soil dry density × loose spreading thickness of raw soil × loose spreading coefficient of raw soil × cement spreading area × cement dosage ratio, it is easy to calculate that the grid area of ​​each bag of cement is 2.02m2, and the size of the cement spreading grid is 2m×1m. Use lime to sprinkle the grid, and one bag of cement is placed on each grid. Note that before spreading cement, check that the working condition of the roller and road mixer is normal and the fuel is sufficient;

[0107] Mixing: After the cement is evenly spread, it is mixed with a road mixer. The mixing should be uniform, uniform in color, without gray belts and uneven surfaces. The depth of the road mixer should reach the bottom of the layer. A special person should be assigned to measure the mixing depth with a shovel. No bare soil layer should be left. The road mixer should enter the lower supporting layer 2cm during the second mixing.

[0108] Detect cement admixture dosage: Soil samples are taken from the area after two mixings by the road mixer, and the cement dosage is determined by EDTA titration. If the dosage is not reached, cement should be spread again and mixed again. According to the on-site test, the actual thickness of the site is controlled at about 29cm after paving the 32cm bare soil and compacting with a dry density of 1.76g / cm3, which can guarantee the success rate of the test to a large extent. After sampling, the average value is between 4.0 and 4.1, which fully meets the allowable error requirement of -0.5% to +1%;

[0109] Rolling: After the improved soil is mixed evenly and the ash dosage is tested to be qualified, it is initially leveled by a grader and manual labor, and then rolled by a roller within the full width of the roadbed to the required compaction density, and no obvious tracks should appear. When rolling, the longitudinal lap length shall not be less than 2m, the longitudinal track overlap between rows shall not be less than 40cm, the upper and lower layers of filling joints shall be staggered by not less than 3m, the surface shall always be kept moist, and the rolling speed shall be controlled at 3km / h.

[0110] S4, rolling and leveling, use a roller for preliminary rolling, then use a grader and manual methods for fine leveling and repairing, and finally use a heavy roller for compaction to ensure that the foundation surface is flat and uniform;

[0111] S41. Preliminary rolling: Use a roller to perform preliminary compaction to ensure that the surface of the cement-improved soil is flat;

[0112] S42, surface leveling: Use a land leveler and manual methods to perform fine leveling and repair local pits and uneven areas;

[0113] S43, Rolling and compaction: Use heavy rollers to roll at the specified compaction density, paying attention to speed, lap length and overlap width;

[0114] S44, rolling quality inspection: Conduct quality inspection after rolling to ensure there are no obvious wheel marks and uneven compaction;

[0115] S45. Filling of insufficient soil: As needed, fill the soil manually after rolling and level the ground again.

[0116] In this step:

[0117] Construction layout: Use the total station to encrypt and re-measure the pile position coordinates, set the middle pile every 20m, measure and set the side piles for filling control in the road trench area, and insert the filling layer control poles at the side piles. Use red paint to mark the paving thickness and width of each layer, and then hang the line for construction. Note that the overfill width on both sides of the roadbed slope should be 30 to 50cm;

[0118] Material spreading and paving: Use a grid pattern to spread the material, and fill the material in horizontal layers, first low and then high, first on the sides and then in the center. When filling the roadway area, it must be filled in horizontal layers in the longitudinal full section according to the designed section. The filling and compaction from the lowest point should not exceed 40cm. Particles of filler exceeding 10cm and other debris should be picked out;

[0119] Rough leveling, fine leveling, and static pressing: Calculate the amount of soil and cement, set up a height control line to control the loose paving thickness (no more than 35cm), and use a bulldozer to rough-level the filler first, and then use a grader to fine-level it. The surface must be flat and uniform so that the cement can be spread and mixed;

[0120] Cement spreading: Use advanced cement spreaders to spread cement, use CNC technology to control the amount of cement spread, and strictly control key parameters such as driving speed and cement spraying flow rate. It is strictly forbidden to adjust related parameters at will during the construction process;

[0121] Mixing cement soil: Use a road mixer to mix cement soil. A dedicated person should follow the road mixer to check the mixing depth at any time and cooperate with the road mixer operator to adjust the mixing depth. It is strictly forbidden to leave a "plain soil" interlayer at the bottom of the mixing layer. When mixing, the surface of the 2cm lower bearing layer should be slightly damaged to facilitate the adhesion of the upper and lower layers. After mixing evenly, the test personnel and the supervisor will simultaneously take samples to measure the water content and cement dosage to ensure that the cement content is qualified and the cement soil mixing is uniform;

[0122] Leveling and compaction: After the cement-improved soil is mixed, use a 22t roller to quickly statically compact it, and then use a grader to fine-level it. Manually fill the local potholes and uneven areas in time; after the roadbed surface is finely leveled, use a heavy roller to roll it within the full width of the roadbed to the required compaction density. After rolling, there should be no obvious rolling wheel marks on the surface. When rolling, the intersections of each section should overlap and compact each other, and the longitudinal overlap length should not be less than 2.0m. When rolling, overlap 1 / 3 of the wheel width, and the wheel tracks between the longitudinal rows should overlap by no less than 40cm. The upper and lower filling joints should be staggered by no less than 3.0m. The longitudinal overlap mixing length between the two working sections should not be less than 2.0m. Rolling follows the principle of "static pressure first, then vibration, light first, then heavy, fast first, then slow, first the sides, then the middle". The maximum rolling speed of the roller is no more than 3km / h. Rolling adopts "two dynamic and two static". After that, the test will start. If the test results cannot meet the design requirements, "one dynamic and one static" will be used to repeat the construction and test. For each unit constructed, it is required to record the compaction thickness, number of rolling times, and test results and compare them. The construction is terminated until the design requirements are met.

[0123] S5. Testing and quality control: use the sand filling method to test the density of the improved soil, conduct quality inspection on the compacted foundation, and record and compare the compaction thickness, number of times and test results;

[0124] S51. Post-compaction inspection: Use the sand filling method to inspect the density of the improved soil to ensure that it meets the design requirements;

[0125] S52. Check quality: Check the quality of the compacted foundation, including surface flatness and uniformity;

[0126] S53. Record and compare: record the rolling thickness, number of passes and test results, and compare them with the design requirements;

[0127] S54, Improvement and treatment: Repair and reinforce the sections that do not meet the requirements;

[0128] S55. Final confirmation: The last test confirms that the compaction degree meets the design requirements and ensures the quality of the foundation.

[0129] In this step:

[0130] Vibration compaction: After the cement soil is rolled, the compaction degree should be tested in time. If it is qualified, the rolling can be stopped and curing can be carried out. Antifreeze measures should be taken for cement soil in winter. The test section is rolled in a "1-1-N-1" combination, that is, 1 static pressure (22t roller), 1 weak vibration (22t roller), N strong vibrations (22t roller), and 1 static pressure (22t roller). The entire rolling work is guaranteed to be completed before the failure of the slow-setting cement (initial setting of cement).

[0131] Testing: The sand filling method uses sand of uniform particles (or single particle size) to fall from a certain height into a cylinder or hole of a specified volume. Based on the principle that its unit mass is constant, the volume of the test hole is measured, and the volume of the test hole is used to represent the volume of the material taken out of the hole. This method can be used to test the density of various soils or road surface materials.

[0132] Records: Repeat testing to determine the completeness and accuracy of the data to obtain the final quality results.

[0133] S6, maintenance and subsequent treatment, carry out maintenance work on cement soil to prevent freezing, monitor the rolling process and make necessary optimizations, and finally make final confirmation to ensure that the construction quality meets the requirements;

[0134] S61. Post-rolling maintenance: perform maintenance work on the cement soil, keep it moist and avoid freezing;

[0135] S62. Antifreeze measures: Take appropriate antifreeze measures during winter construction to ensure construction quality;

[0136] S63. Optimization of rolling method: Use appropriate rolling method to avoid excessive damage to the improved soil structure;

[0137] S64. Monitor the rolling process: monitor the rolling speed and make necessary adjustments to ensure uniformity;

[0138] S65. Final confirmation: Carry out final inspection and confirmation to ensure that the foundation construction meets the requirements.

[0139] In order to ensure the construction quality of step S1 and steps S2-S6, precise construction parameter control must be adopted. High-precision measuring equipment and information management systems are needed to accurately control material usage, tamping energy, admixture uniformity and thickness setting, including but not limited to real-time monitoring of soil moisture, compaction and deformation, and timely adjustment of parameters during the construction process.

[0140] Before the cushion layer compaction method of step S1 is used, underground obstacles and mud-sinking red clay of different thicknesses are identified through geological exploration and ground scanning technology, so as to carry out comprehensive pretreatment of the construction area. This technical feature ensures comprehensive improvement from the deep foundation to the surface layer, and reduces the uncertainty and variability that may cause construction quality risks.

[0141] In order to ensure the strength and durability of the cement-improved soil, step S6 introduces maintenance and strengthening measures, which include traditional moist maintenance and temperature control, as well as additional reinforcement of the foundation using new epoxy resin coatings, fiber reinforcement and other technologies. These measures can improve the foundation's anti-freezing and anti-penetration properties, enhance its bearing capacity and extend its life.

[0142] Working principle:

[0143] The present invention combines the excellent properties of the cushion layer dynamic compaction method and cement improved soil to treat the foundation of a general airport runway, improve the bearing capacity of the foundation soil, and reduce foundation deformation. This combined method can significantly enhance the stability and safety of the foundation during the construction of the foundation in the collapsible loess area and during the take-off and landing of the aircraft. It not only reduces the construction difficulty, but also reduces the construction cost. More importantly, this method can effectively reduce the harm caused by the collapsibility of loess, thereby ensuring the quality of the project after construction. During the construction process, this method can significantly reduce the construction difficulty. Due to the strong vibration force generated by the cushion layer dynamic compaction method, the foundation soil layer is easy to compact, thereby reducing the dependence on large-scale construction equipment. At the same time, the high-strength characteristics of cement improved soil make the foundation more stable and reduce construction risks. In addition, the combined use of the cushion layer dynamic compaction method and cement improved soil can greatly improve the bearing capacity and stability of the foundation, so the amount of foundation treatment can be reduced, the construction period can be shortened, and the construction cost can be reduced;

[0144] On the other hand, this method can also effectively reduce the damage caused by the collapsibility of loess. The collapsibility of loess can cause the foundation to sink and deform, seriously affecting the stability and safety of the airport runway. The present invention can effectively improve the collapsibility of loess and improve the stability and safety of the foundation through the combined use of the cushion layer strong tamping method and cement improved soil.

[0145] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A foundation construction method based on the red clay area dynamic tamping method and cement improved soil, It is characterized in that The steps include: S1. Construction of cushion layer by dynamic compaction method: Select the cushion layer by dynamic compaction method, determine the compaction energy, compaction hammer specifications and lifting wire rope requirements, determine the construction technical parameters in the test area, carry out compaction construction, and finally fill the compaction pit; S2. Preparation for cement-improved soil construction: determine the parameters for cement and plain soil, level the underlying layer and compact it, and after laying out the lines to determine the thickness and position, prepare the plain soil and perform water content and cement admixture measurements; S3, spreading of raw soil and cement, spreading raw soil on the underlying layer in a horizontal layered filling manner, spreading cement and mixing with a road mixer to ensure uniformity and mixing quality; S4, rolling and leveling, use a roller for preliminary rolling, then use a grader and manual methods for fine leveling and repairing, and finally use a heavy roller for compaction to ensure that the foundation surface is flat and uniform; S5. Testing and quality control: use the sand filling method to test the density of the improved soil, conduct quality inspection on the compacted foundation, and record and compare the compaction thickness, number of times and test results; S6, maintenance and subsequent treatment, carry out maintenance work on cement soil to prevent freezing, monitor the rolling process and optimize it, and finally make final confirmation to ensure that the construction quality meets the requirements; The step S1 can be refined as follows: S11. Confirmation of design requirements: confirm the cushion treatment depth, tamping energy and tamping hammer specifications, as well as the requirements for the lifting wire rope of the dynamic tamping machine; S12. Determine the test area: select the test area and conduct test tamping to select the construction technical parameters; S13, tamping point layout: clean and level the site and lay a gravel cushion layer, and mark the first tamping point position; S14. Selection of lifting wire rope: Select appropriate lifting wire rope according to the weight of the rammer and the safety factor; S15, Ramming construction: put the ramming hammer in place, ram according to regulations and carry out relevant elevation measurements; S16, Completion of dynamic compaction: Use a bulldozer to fill the compaction pit and conduct the final elevation measurement; The step S2 can be refined as follows: S21. Parameter determination: Determine the usage parameters of cement and soil to ensure that the design requirements are met; S22, leveling of the lower bearing layer: Use a grader to level and compact the lower bearing layer; S23, measurement and setting out: use the total station to determine the pile position, and set out the lines to mark the control points and the thickness and width positions; S24, Raw soil preparation: clean the site and lay a gravel cushion layer to prepare raw soil; S25, moisture content determination: Determine the moisture content of the raw soil and determine the loose paving thickness coefficient; S26. Cement admixture determination: Determine the actual cement spreading area and cement admixture amount, and conduct cement admixture testing.

2. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, It is characterized in that The step S3 can be refined as follows: S31, Material laying and paving: According to the design requirements, the soil is spread on the underlying layer, using the horizontal layered filling method, and particles and debris are removed; S32, Cement spreading: Use cement spreading vehicle to spread evenly, strictly control the spreading amount and related parameters; S33, Mixing: Use a road mixer to mix the soil and cement to ensure uniformity and color; S34, cement content test: test whether the cement content in cement mixed soil is qualified; S35. Confirmation of mixing depth: Confirm the mixing depth to ensure that cement and soil are evenly mixed.

3. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, It is characterized in that The step S4 can be refined as follows: S41. Preliminary rolling: Use a roller to perform preliminary compaction to ensure that the surface of the cement-improved soil is flat; S42, surface leveling: Use a land leveler and manual methods to perform fine leveling and repair local pits and uneven areas; S43, Rolling and compaction: Use heavy rollers to roll at the specified compaction density, paying attention to speed, lap length and overlap width; S44, rolling quality inspection: Conduct quality inspection after rolling to ensure there are no obvious wheel marks and uneven compaction; S45. Filling of insufficient soil: As needed, fill the soil manually after rolling and level the ground again.

4. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, It is characterized in that The step S5 can be refined as follows: S51. Post-compaction inspection: Use the sand filling method to inspect the density of the improved soil to ensure that it meets the design requirements; S52. Check quality: Check the quality of the compacted foundation, including surface flatness and uniformity; S53. Record and compare: record the rolling thickness, number of passes and test results, and compare them with the design requirements; S54, Improvement and treatment: Repair and reinforce the sections that do not meet the requirements; S55. Final confirmation: The last test confirms that the compaction degree meets the design requirements and ensures the quality of the foundation.

5. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, It is characterized in that The step S6 can be refined as follows: S61. Post-rolling maintenance: perform maintenance work on the cement soil, keep it moist and avoid freezing; S62. Antifreeze measures: Take appropriate antifreeze measures during winter construction to ensure construction quality; S63. Optimization of rolling method: Use appropriate rolling method to avoid excessive damage to the improved soil structure; S64, monitor the rolling process: monitor the rolling speed and adjust it to ensure uniformity; S65. Final confirmation: Carry out final inspection and confirmation to ensure that the foundation construction meets the requirements.

6. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, Features: In order to ensure the construction quality of step S1 and steps S2-S6, precise construction parameter control must be adopted. High-precision measuring equipment and information management systems are needed to accurately control material usage, tamping energy, admixture uniformity and thickness setting, including but not limited to real-time monitoring of soil moisture, compaction and deformation, and timely adjustment of parameters during the construction process.

7. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, Features: Before the cushion layer compaction method of step S1 is used, underground obstacles and mud-sinking red clay of different thicknesses are identified through geological exploration and ground scanning technology, so as to carry out comprehensive pretreatment of the construction area, ensure comprehensive improvement from the deep foundation to the surface layer, and reduce uncertainty and variability that may cause construction quality risks.

8. A foundation construction method based on red clay area dynamic tamping method and cement improved soil according to claim 1, Features: In order to ensure the strength and durability of the cement-improved soil, step S6 introduces maintenance and strengthening measures, which include traditional moist maintenance and temperature control, as well as additional reinforcement of the foundation using new epoxy resin coatings and fiber reinforcement technology. These measures can improve the foundation's anti-freezing and anti-penetration properties, enhance its bearing capacity and extend its life.

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