Building foundation engineering construction method

Abstract

The invention belongs to the field of foundation engineering construction, and provides a building foundation engineering construction method which comprises the following steps: S1, geological improvement, cushion construction and expansive soil treatment; s2, prefabricated foundation components are assembled; s3, intelligent reinforcement cage construction; s4, concrete pouring and curing; and S5, performing quality verification and data archiving. The lime and coal ash mixed curing layer is adopted to inhibit ion exchange expansion, the expansion coefficient of expansive soil is reduced, liquid water permeation is blocked through the breathable film, gaseous water diffusion is allowed, damage to a film body caused by air pressure is reduced, temperature rise and deformation data are fed back in real time through the sensor network embedded in the reinforcement cage, pouring parameters are dynamically adjusted, and the construction quality is improved. A point cloud model is generated through three-dimensional laser scanning, an acceptance report is generated by comparing with BIM design deviation, manual measurement is replaced, the acceptance efficiency is higher, and whole-process intelligent monitoring can be achieved.

Description

Technical Field

[0001] The invention belongs to the field of foundation engineering construction, in particular to a building foundation engineering construction method. Background Art

[0002] The foundation refers to the soil or rock mass beneath a building that supports its foundation. The soil layers that form a building's foundation can be classified as rock, crushed stone, sand, silt, clay, and artificial fill. There are two types of foundations: natural and artificial. Natural foundations are naturally occurring soil layers that do not require reinforcement, while artificial foundations do require reinforcement.

[0003] During the foundation construction process, expansive soil layers will be encountered. Expansive soil is hard or hard plastic under normal natural conditions, but its bearing capacity decreases when it comes into contact with water and its properties are extremely unstable. When the expansive soil absorbs water, its volume expands, causing the buildings on it to bulge. When it loses water, its volume shrinks, causing the soil to crack and the buildings on it to sink. Repeated expansion and contraction deformation is very harmful to the foundation of the building. When the expansive soil layer is thick and there is a low-rise building on top, the harm caused is even greater.

[0004] For example, Chinese patent publication number CN102352639A discloses a method for treating the expansion stress of expansive soil foundations, belonging to the field of construction technology. This method involves laying sand on a foundation cushion to form a buffer layer; an isolation layer is provided between the buffer layer and the structural layer. Compared to building materials such as concrete and bricks, the sand cushion in the buffer layer can slide under external forces. Using a sand cushion can eliminate the adverse effects of foundation expansion stress on the building. The isolation layer, such as linoleum felt or plastic film, is impermeable when intact, preventing leakage during concrete pouring and preventing the sand cushion from consolidating.

[0005] However, this method directly uses tarpaulin, plastic film, etc., which are waterproof when in good condition. However, tarpaulin and plastic film are easily damaged, thereby losing their waterproof properties, resulting in extremely unstable results of this method, and the sand cushion layer cannot effectively eliminate the foundation expansion stress. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a construction method for building foundation engineering to solve the problems mentioned in the background technology.

[0007] A construction method for a building foundation project comprises the following steps: S1. Geological improvement and cushion construction and expansive soil treatment; S2, assembly of prefabricated foundation components; S3, intelligent steel cage construction; S4, concrete pouring and curing; S5, quality verification and data archiving; Specifically, the S1 includes the following steps: S101. Site pretreatment: Use pipe wells for dewatering, with a well spacing of 15m. The well depth should ensure that the well bottom is at least 2m below the base elevation and the water level drops to 0.5m below the working surface. Pump water continuously until the cushion layer is completed, and remove the miscellaneous fill to the bearing layer. Replace the weak areas with sand and gravel, with a replacement thickness of ≥500mm, and ensure a compaction coefficient ≥0.97, that is, a compaction degree ≥97%; S102, Gravel cushion layer configuration: Select 5mm to 40mm gravel for configuration, the gravel cushion layer thickness is 400mm to 600mm, the thickness of each grade of gravel cushion layer is 200mm to 300mm, use 22t vibratory roller to perform 1 to 2 static compaction and 5 to 6 vibration compaction, after compaction, every 500m 2 Conduct a sand filling method to measure the compaction degree; S103. Special treatment of expansive soil.

[0008] Preferably, the special treatment of expansive soil in S103 includes the following steps: S1031. Identification and zoning of expansive soils: Take undisturbed soil samples and conduct a free expansion rate test. Montmorillonite content is tested using X-ray diffraction. Contents ≥ 15% require special treatment. Undisturbed soil samples with a free expansion rate δef > 40% are classified as strongly expansive soils; 30% ≤ δef ≤ 40% are classified as moderately expansive soils; and δef < 30% are classified as weakly expansive soils. S1032. For lime fly ash solidification layer construction, mix lime powder and fly ash in a lime powder:fly ash mass ratio of 1:4. After mixing, add water and stir with the lime fly ash mixture in a water:lime fly ash mass ratio of 1:0.2-0.25. The water content of the mixture should meet the standard of "holding in a ball in hand but falling apart when touched"; S1033. Paving and Compaction: The mixed lime powder and fly ash are transported to the paving area by a mixture truck for paving to a thickness of 240 mm. The mixture is then leveled using a motor grader. A 22t roller performs one static compaction pass at a speed of 2 km / h. The roller then performs four vibratory compaction passes at a frequency of 30 Hz and an amplitude of 1.5 mm. Finally, a rubber-tyred roller performs final compaction to eliminate wheel marks. S1034. Waterproof and breathable geomembrane laying: Select a thickness of 0.8mm±0.1mm and a permeability coefficient of ≤1.0×10 ～11 m / s, air permeability ≤ 200g / m² / 24h, tensile strength ≥ 25kN / m in longitudinal / transverse direction, overlap several waterproof breathable geomembranes with an overlap width of 150mm and a deviation ≤ ±10mm, and weld them at a welding temperature of 380℃±20℃ and a speed of 1.5m~2m / min; S1035, ventilation duct layout; S1036. On-site acceptance and rainfall emergency plan.

[0009] Preferably, the ventilation ducts in S1035 are arranged specifically as follows: a number of PVC ventilation ducts with a diameter of 50 mm are arranged under the waterproof and breathable geomembrane, and a grid arrangement with a spacing of 5 m × 5 m is adopted, and the PVC ventilation ducts are 300 mm above the ground, and a one-way ventilation valve is provided inside each PVC ventilation duct, and a ventilation cap with both insect-proof and rain-proof functions is provided on the top of each PVC ventilation duct.

[0010] Preferably, the on-site acceptance and rainfall emergency plan in S1036 are specifically as follows: the expansion rate is detected by a portable dilatometer, and then the moisture content under the membrane is detected by a neutron moisture meter, and the membrane integrity rate is detected by an electric spark detector. The rainfall emergency plan is specifically as follows: through meteorological warning, it is determined whether the precipitation is greater than 10mm / h. If it is greater, the surface of the waterproof and breathable geomembrane is covered with waterproof canvas, and the PVC breathable duct drain valve is opened for drainage. If it is less than, normal construction is carried out.

[0011] Preferably, the assembly of the prefabricated foundation components in S2 is specifically as follows: coordinate positioning is performed by a total station with an error of ≤2mm, 30mm thick M30 mortar is laid on the bottom of the pedestal for leveling, and then the pedestals are connected by high-strength bolts, and the connection seams are poured with non-shrinkage epoxy mortar.

[0012] Preferably, the construction of the intelligent steel cage in S3 specifically includes the following steps: S301, sensor deployment topology; S302, mechanical sleeve connection; Specifically, the S301 is as follows: a temperature and humidity sensor is installed at the steel cage column foot node, and the temperature and humidity sensor is fixed to the inner side of the main reinforcement by a wire tie between the steel cage column foot node, avoiding the welding point ≥100mm, and an optical fiber strain gauge is set in the middle section of the column. The optical fiber of the optical fiber strain gauge is spirally wound along the column reinforcement with a pitch of 500mm. A three-dimensional stress sensor is set at the junction of the beam and the column, and the wires of the three-dimensional stress sensor, temperature and humidity sensor and optical fiber strain gauge are passed through a PVC pipe and led to the data box outside the foundation.

[0013] Preferably, the S302 specifically comprises: grinding the end face of the steel bar, then pre-screwing the sleeve, final-tightening it with a torque wrench and spraying it with red paint to mark it.

[0014] Preferably, the concrete pouring and curing in S4 specifically includes the following steps: S401. Low hydration heat concrete preparation: P·O42.5 cement, Class II fly ash, and retarding water reducer, wherein the weight of the Class II fly ash is 30% of the weight of the P·O42.5 cement, and the weight of the retarding water reducer is 1.8% of the weight of the P·O42.5 cement. The P·O42.5 cement, Class II fly ash, and retarding water reducer are mixed to form low hydration heat concrete, and then poured. S402. Operation of the intelligent temperature control system: Temperature sensors are installed on the side of the concrete and outside, and cooling water pipes are laid in the concrete. The layout spacing of the cooling water pipes is 800mm×800mm, the water inlet temperature is ≤15℃, and an insulation pad made of paraffin / fatty acid composite phase change material is set to insulate the concrete surface. The covering time of the insulation pad must be greater than or equal to 7 days. The external temperature and concrete temperature are detected by the set temperature sensors, and the detection results are transmitted to the cloud platform for calculation and analysis to analyze whether the temperature difference is greater than 25℃. If it is greater than 25℃, the cooling water flow in the cooling water pipe is increased. If it is not greater than 25℃, the current cooling water flow parameters are maintained.

[0015] Preferably, the quality verification and data archiving in S5 are specifically as follows: three-dimensional laser scanning is performed by a TrimbleX7 scanner, and point cloud processing is performed to generate a triangular mesh model, which is superimposed with the design model, the deviation value is displayed through a color difference map, and a digital report is generated based on the deviation value.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses a mixed solidification layer of lime and fly ash to inhibit ion exchange expansion, reduce the expansion coefficient of expansive soil, and block liquid water penetration through the breathable membrane, allowing gaseous water to diffuse, reducing damage to the membrane due to air pressure. In the dry season, the exhaust pipe can discharge volatile water vapor in the soil to reduce expansion pressure. In the rainy season, the one-way air valve can prevent external water from penetrating, thereby balancing the air pressure under the breathable membrane and preventing the membrane from swelling and rupture.

[0017] 2. The present invention uses prefabricated foundation beams and pedestal modules in factory production and direct on-site assembly, which reduces 80% of the time for formwork erection and dismantling, avoids wet operations such as applying release agents, and significantly improves the assembly speed compared to traditional cast-in-place construction. In addition, pre-buried wireless temperature and humidity sensors and fiber optic strain gauges are used for real-time monitoring, and the cooling water flow is dynamically regulated to ensure that the internal and external temperature difference is ≤25°C, effectively suppressing temperature stress cracks. The low-hydration heat concrete with 30% fly ash and the phase change material insulation blanket have a phase change temperature of 28°C, achieving precise temperature control and maintenance.

[0018] 3. The present invention uses a pre-embedded sensor network in the steel cage to feed back temperature rise and deformation data in real time, dynamically adjusts the pouring parameters, generates a point cloud model through three-dimensional laser scanning, and generates an acceptance report by comparing BIM design deviations, replacing manual measurement. The acceptance efficiency is higher and intelligent monitoring of the entire process can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the method of the present invention; Figure 2 This is a flow chart of expansive soil treatment in the present invention; Figure 3 This is a flow chart of the rainfall emergency plan in the present invention; Figure 4 This is a flow chart of the operation of the intelligent temperature control system in the present invention. DETAILED DESCRIPTION

[0020] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0021] See Figure 1 As shown, this embodiment is a construction method for a building foundation engineering, comprising the following steps: S1. Geological improvement and cushion construction and expansive soil treatment; Specifically, the S1 includes the following steps: S101. Site pretreatment: Use pipe wells for dewatering, with a well spacing of 15m. The well depth should ensure that the well bottom is at least 2m below the base elevation and the water level drops to 0.5m below the working surface. Continuous pumping should be carried out until the cushion layer construction is completed. This can block groundwater interference and prevent the base from softening. Miscellaneous fill soil should be removed to the bearing layer. Weak areas should be replaced with sand and gravel with a thickness of ≥500mm. The compaction coefficient should be ≥0.97, that is, the compaction degree should be ≥97%. This will eliminate the risk of uneven settlement and form a homogeneous bearing layer, thereby creating a stable dry working surface. S102, Gravel cushion layer grading configuration: Select 5mm to 40mm gravel for graded configuration, optimize gradation and improve density, the gravel cushion layer thickness is 400mm to 600mm, the thickness of each grade of gravel cushion layer is 200mm to 300mm, use 22t vibratory roller to perform 1 to 2 static compaction and 5 to 6 vibration compaction to avoid excessive vibration causing gravel breakage, every 500m after compaction 2 Conduct a sand filling method to measure the compaction degree; See Figure 2 As shown, S103, special treatment of expansive soil; The special treatment of expansive soil in S103 includes the following steps: S1031. Identification and zoning of expansive soils: Untouched soil samples are tested for free expansion rate and montmorillonite content using X-ray diffraction. Montmorillonite content ≥ 15% requires special treatment. Untouched soil samples with a free expansion rate δef > 40% are classified as strongly expansive soils; 30% ≤ δef ≤ 40% are classified as moderately expansive soils; and δef < 30% are classified as weakly expansive soils. Treatment levels are scientifically determined, and quantitative analysis of mineral composition is performed to improve identification accuracy. S1032. Construction of the lime fly ash solidification layer: Mix lime powder and fly ash in a lime powder: fly ash mass ratio of 1:4. After mixing, add water and stir the lime fly ash mixture in a water: lime fly ash mass ratio of 1:0.2-0.25. Ion exchange between the water and lime fly ash mixture reduces the hydrophilicity of the soil. The water content of the mixture should meet the standard of "holding in a ball and falling apart when touched". The corresponding water content, that is, the percentage of water mass to the total mass of dry material, is preferably 16.7%-22.0% to ensure the best compaction effect. S1033. Paving and Compaction: The mixed lime powder and fly ash are transported to the paving area by a mixture transport truck for paving to a thickness of 240 mm. The mixture is then leveled using a motor grader. A 22t roller performs one static compaction pass at a speed of 2 km / h. The roller then performs four vibratory compaction passes at a frequency of 30 Hz and an amplitude of 1.5 mm to prevent aggregate separation caused by excessive compaction. A rubber-tyred roller performs final compaction to eliminate wheel marks, thereby eliminating microcracks and improving surface sealing. S1034. Waterproof and breathable geomembrane laying: Select a thickness of 0.8mm±0.1mm and a permeability coefficient of ≤1.0×10 ～11 m / s, air permeability ≤200g / m² / 24h, tensile strength longitudinal / transverse ≥25kN / m waterproof breathable geomembrane, so that the waterproof breathable geomembrane can resist foundation deformation stress, overlap several waterproof breathable geomembranes with an overlap width of 150mm and a deviation of ≤±10mm, and weld them at a welding temperature of 380℃±20℃ and a speed of 1.5m~2m / min, which can ensure long-term airtightness of the joints, allow soil gas to escape, and prevent pressure accumulation under the membrane; S1035, ventilation duct layout; See Figure 3 As shown, S1036, site acceptance and rainfall emergency plan; The specific arrangement of the air ducts in S1035 is as follows: a number of PVC air ducts with a diameter of 50mm are arranged under the waterproof and breathable geomembrane, and each PVC air duct is arranged in a grid with a spacing of 5m×5m to achieve full-area gas drainage, and the PVC air duct is 300mm above the ground. A one-way air valve is provided inside each PVC air duct, and a breathable cap with both insect-proof and rain-proof functions is provided on the top of each PVC air duct to prevent backflow and biological blockage; in specific practice, the part of the PVC air duct above the ground is covered with a breathable anti-collision steel pipe to avoid mechanical damage and extend the service life; in specific practice, an electric air pump connected to the PVC air duct can also be provided under the waterproof and breathable geomembrane. When the air pressure under the waterproof and breathable geomembrane is too high, the electric air pump is turned on to quickly extract the gas under the membrane and discharge it to the outside of the membrane through the PVC air duct, which can quickly adjust the air pressure under the membrane and prevent the waterproof and breathable geomembrane from excessive deformation, swelling or even rupture.

[0022] The on-site acceptance and rainfall emergency plan in S1036 are specifically as follows: expansion rate detection by portable dilatometer, moisture content under the membrane by neutron moisture meter, and membrane integrity detection by spark detector. The rainfall emergency plan is specifically as follows: whether the precipitation is greater than 10mm / h is determined by meteorological warning. If it is greater than 10mm / h, waterproof canvas is covered on the surface of the waterproof and breathable geomembrane, and the PVC ventilation conduit drain valve is opened for drainage. If it is less than 10mm / h, normal construction is carried out to prevent rainwater intrusion and soil expansion. S2, assembly of prefabricated foundation components; The assembly of the prefabricated foundation components in S2 is specifically as follows: coordinate positioning is performed using a total station with an error of ≤2mm, 30mm thick M30 mortar is laid on the bottom of the pedestal for leveling, and then the pedestals are connected by high-strength bolts. Non-shrinkage epoxy mortar is poured into the joints to ensure the precise spatial position of the structure. The M30 mortar leveling layer can compensate for microscopic unevenness of the base, and the pouring of non-shrinkage epoxy mortar can eliminate the hidden danger of water seepage in the joints. S3, intelligent steel cage construction; The construction of the intelligent steel cage in S3 specifically includes the following steps: S301, sensor deployment topology; S302, mechanical sleeve connection; Specifically, the S301 is specifically as follows: installing a temperature and humidity sensor at the steel cage column foot node, fixing the temperature and humidity sensor to the steel cage column foot node on the inner side of the main reinforcement by tying wire, avoiding the welding point ≥100mm to prevent high-temperature welding from damaging the sensor, and setting an optical fiber strain gauge in the middle section of the column. The optical fiber of the optical fiber strain gauge is spirally wound along the column reinforcement with a pitch of 500mm. A three-dimensional stress sensor is set at the intersection of the beam and column. The wires of the three-dimensional stress sensor, temperature and humidity sensor, and optical fiber strain gauge are led through a PVC pipe to the data box outside the foundation. The PVC pipe protects the wires to ensure signal transmission stability. The S302 specifically includes: grinding the end face of the steel bar, then pre-screwing the sleeve, final-tightening it with a torque wrench, and spraying red paint marks to make the operation visual; S4, concrete pouring and curing; The concrete pouring and curing in S4 specifically includes the following steps: S401. Low hydration heat concrete configuration: P·O42.5 cement, Grade II fly ash, and a retarding water reducer, wherein the weight of the Grade II fly ash is 30% of the weight of the P·O42.5 cement, and the weight of the retarding water reducer is 1.8% of the weight of the P·O42.5 cement. The P·O42.5 cement, Grade II fly ash, and retarding water reducer are mixed to form low hydration heat concrete, which is then poured. Replacing 30% of the cement with fly ash powder reduces the total hydration heat, and the retarding water reducer extends the initial setting time, improves workability, and thereby suppresses temperature cracking. See Figure 4 As shown, S402, the operation of the intelligent temperature control system: temperature sensors are set on the side of the concrete and the outside, and cooling water pipes are laid in the concrete. The layout spacing of the cooling water pipes is 800mm×800mm, the water inlet temperature is ≤15°C, and an insulation pad made of paraffin / fatty acid composite phase change material is set to insulate the concrete surface. The insulation pad is covered for more than or equal to 7 days. The external temperature and the concrete temperature are detected by the set temperature sensor, and the detection results are transmitted to the cloud platform for calculation and analysis to analyze whether the temperature difference is greater than 25°C. If it is greater than 25°C, the cooling water flow in the cooling water pipe is increased. If it is not greater than 25°C, the current cooling water flow parameters are maintained. The cooling water pipe and the insulation pad play a role of internal and external coordinated temperature control, and the temperature difference analysis is performed through the cloud platform to dynamically adjust the cooling water flow; S5, quality verification and data archiving; The quality verification and data archiving in S5 are as follows: 3D laser scanning is performed by Trimble X7 scanner, and point cloud processing is performed to generate a triangular mesh model, which is superimposed on the design model. The deviation value is displayed through the color difference map, and a digital report is generated based on the deviation value. The 3D laser scanning and point cloud processing can achieve millimeter-level geometric deviation detection, and through The color difference map can visually locate quality defect areas, and digital reports can provide benchmark data for the operation and maintenance stage, thereby achieving digital completion and delivery.

[0023] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present invention. Any changes, modifications, replacements and variations of the above embodiments by ordinary technicians in this field within the scope of the present invention should be included in the scope of protection of the present invention.

Claims

1. A construction method for a building foundation project, characterized in that: The following steps are involved: S1. Geological improvement and cushion construction and expansive soil treatment; S2, assembly of prefabricated foundation components; S3, intelligent steel cage construction; S4, concrete pouring and curing; S5, quality verification and data archiving; Specifically, the S1 includes the following steps: S101. Site pretreatment: Use pipe wells for dewatering, with a well spacing of 15m. The well depth should ensure that the well bottom is at least 2m below the base elevation, and the water level drops to 0.5m below the working surface. Pump water continuously until the cushion layer construction is completed, and remove the miscellaneous fill to the bearing layer. Replace the weak areas with sand and gravel, with a replacement thickness of ≥500mm and a compaction coefficient of ≥0.

97. S102, Gravel cushion layer configuration: Select 5mm to 40mm gravel for configuration, the gravel cushion layer thickness is 400mm to 600mm, the thickness of each grade of gravel cushion layer is 200mm to 300mm, use 22t vibratory roller to perform 1 to 2 static compaction and 5 to 6 vibration compaction, after compaction, every 500m 2 Conduct a sand filling method to measure the compaction degree; S103. Special treatment of expansive soil.

2. A construction method for building foundation engineering according to claim 1, characterized in that: The special treatment of expansive soil in S103 includes the following steps: S1031. Identification and zoning of expansive soils: Take undisturbed soil samples and conduct a free expansion rate test. Montmorillonite content is tested using X-ray diffraction. Contents ≥ 15% require special treatment. Undisturbed soil samples with a free expansion rate δef > 40% are classified as strongly expansive soils; 30% ≤ δef ≤ 40% are classified as moderately expansive soils; and δef < 30% are classified as weakly expansive soils. S1032, lime fly ash solidification layer construction, take lime powder and fly ash and mix them, the mass ratio of lime powder to fly ash is 1:4, after mixing, take water and stir the lime fly ash mixture, the mass ratio of water to lime fly ash mixture is 1:0.2-0.25; S1033. Paving and Compaction: The mixed lime powder and fly ash are transported to the paving area by a mixture truck for paving to a thickness of 240 mm. The mixture is then leveled using a motor grader. A 22t roller performs one static compaction pass at a speed of 2 km / h. The roller then performs four vibratory compaction passes at a frequency of 30 Hz and an amplitude of 1.5 mm. Finally, a rubber-tyred roller performs final compaction to eliminate wheel marks. S1034. Waterproof and breathable geomembrane laying: Select a thickness of 0.8mm±0.1mm and a permeability coefficient of ≤1.0×10 ～11 m / s, air permeability ≤ 200g / m² / 24h, tensile strength ≥ 25kN / m in longitudinal / transverse direction, overlap several waterproof breathable geomembranes with an overlap width of 150mm and a deviation ≤ ±10mm, and weld them at a welding temperature of 380℃±20℃ and a speed of 1.5m~2m / min; S1035, ventilation duct layout; S1036. On-site acceptance and rainfall emergency plan.

3. A construction method for building foundation engineering according to claim 2, characterized in that: The specific arrangement of the breathable ducts in S1035 is as follows: a number of PVC breathable ducts with a diameter of 50 mm are laid under the waterproof and breathable geomembrane, arranged in a grid with a spacing of 5m×5m, and the PVC breathable ducts are 300mm above the ground. A one-way breathable valve is provided inside each PVC breathable duct, and a breathable cap with both insect-proof and rain-proof functions is provided on the top of each PVC breathable duct.

4. A construction method for building foundation engineering according to claim 2, characterized in that: The on-site acceptance and rainfall emergency plan in S1036 are specifically as follows: the expansion rate is tested by a portable dilatometer, the moisture content under the membrane is tested by a neutron moisture meter, and the membrane integrity rate is tested by an electric spark detector. The rainfall emergency plan is specifically as follows: whether the precipitation is greater than 10mm / h is determined by meteorological warning. If it is greater than 10mm / h, the surface of the waterproof and breathable geomembrane is covered with waterproof canvas, and the PVC breathable duct drain valve is opened for drainage. If it is less than 10mm / h, normal construction is carried out.

5. A construction method for building foundation engineering according to claim 1, characterized in that: The assembly of the prefabricated foundation components in S2 is specifically as follows: coordinate positioning is performed by a total station with an error of ≤2mm, 30mm thick M30 mortar is laid on the bottom of the pedestal for leveling, and then the pedestals are connected by high-strength bolts, and the connection seams are poured with non-shrinkage epoxy mortar.

6. A construction method for building foundation engineering according to claim 1, characterized in that: The construction of the intelligent steel cage in S3 specifically includes the following steps: S301, sensor deployment topology; S302, mechanical sleeve connection; Specifically, the S301 is as follows: a temperature and humidity sensor is installed at the steel cage column foot node, and the temperature and humidity sensor is fixed to the inner side of the main reinforcement by a wire tie between the steel cage column foot node, avoiding the welding point ≥100mm, and an optical fiber strain gauge is set in the middle section of the column. The optical fiber of the optical fiber strain gauge is spirally wound along the column reinforcement with a pitch of 500mm. A three-dimensional stress sensor is set at the junction of the beam and the column, and the wires of the three-dimensional stress sensor, temperature and humidity sensor and optical fiber strain gauge are passed through a PVC pipe and led to the data box outside the foundation.

7. A construction method for building foundation engineering according to claim 6, characterized in that: The S302 specifically includes: grinding the end face of the steel bar, pre-screwing the sleeve, final-tightening it with a torque wrench, and spraying a red paint mark.

8. A construction method for building foundation engineering according to claim 1, characterized in that: The concrete pouring and curing in S4 specifically includes the following steps: S401. Low hydration heat concrete preparation: P·O42.5 cement, Class II fly ash, and retarding water reducer, wherein the weight of the Class II fly ash is 30% of the weight of the P·O42.5 cement, and the weight of the retarding water reducer is 1.8% of the weight of the P·O42.5 cement. The P·O42.5 cement, Class II fly ash, and retarding water reducer are mixed to form low hydration heat concrete, and then poured. S402. Operation of the intelligent temperature control system: Temperature sensors are installed on the side of the concrete and outside, and cooling water pipes are laid in the concrete. The layout spacing of the cooling water pipes is 800mm×800mm, the water inlet temperature is ≤15℃, and an insulation pad made of paraffin / fatty acid composite phase change material is set to insulate the concrete surface. The covering time of the insulation pad must be greater than or equal to 7 days. The external temperature and concrete temperature are detected by the set temperature sensors, and the detection results are transmitted to the cloud platform for calculation and analysis to analyze whether the temperature difference is greater than 25℃. If it is greater than 25℃, the cooling water flow in the cooling water pipe is increased. If it is not greater than 25℃, the current cooling water flow parameters are maintained.

9. A construction method for building foundation engineering according to claim 1, characterized in that: The quality verification and data archiving in S5 are specifically as follows: 3D laser scanning is performed by a Trimble X7 scanner, and point cloud processing is performed to generate a triangular mesh model, which is superimposed on the design model, the deviation value is displayed through a color difference map, and a digital report is generated based on the deviation value.

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