Foundation construction method in house building construction

Abstract

The invention discloses a foundation construction method in house building construction, and relates to the technical field of building construction. The method comprises the following steps: step 1, geological investigation and site pretreatment; 2, a shallow soft soil layer is treated; 3, constructing a deep composite pile foundation; 4, laying a composite mattress layer; 5, integrating an intelligent monitoring system; and step 6, quality detection and acceptance. Compared with the prior art, the construction method is more economical and environmentally friendly, the utilization rate of the building residue soil is high, the lime consumption is reduced, carbon emission is reduced, and the material cost is saved; the anti-seismic performance is improved, the anti-seismic intensity of the structure is improved through the elastic concrete layer, and the seismic energy absorption rate is increased; the construction efficiency is improved, and the equipment dismounting time is reduced by the pile casing hole-forming process, so that the construction period is shortened; the adaptability is wider, and the method is suitable for various complex geologies such as collapsible loess, mucky soil and miscellaneous fill.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and particularly to a foundation construction method in house building construction. Background Art

[0002] The foundation refers to the part of the soil mass that bears the influence of the load of the upper structure. The soil mass or rock mass that bears all the loads of the building under the foundation is called the foundation. The foundation does not belong to the component of the building, but it plays a very important role in ensuring the firmness and durability of the building. The upper building cannot be firm without the irreplaceable role of the foundation.

[0003] The existing foundation construction methods have the following problems: 1. Insufficient treatment depth and geological adaptability: The traditional replacement cushion method is only applicable to shallow soft foundations, while the dynamic compaction method and vibroflotation method have limited treatment effects on high-saturation clay or complex geology; 2. Material waste and high cost: Lime piles, cement mixing piles, etc. require a large amount of externally purchased materials, and construction waste is easily generated during construction, which does not meet the requirements of sustainable development; 3. Poor seismic performance: Rigid concrete pile foundations lack elasticity, and seismic waves are easily directly transmitted to the upper structure, resulting in building damage; 4. Low construction efficiency: For example, the casing hole forming requires repeated disassembly and assembly of equipment, and the construction sequence of pile foundations conflicts with the embankment filling, increasing the construction period.

[0004] Therefore, we propose a foundation construction method in house building construction to solve the problems raised above.

[0005] The above information disclosed in this background art is only used to increase the understanding of the background art of the present invention. Therefore, it may include prior art that is not known to those of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a foundation construction method in house building construction to solve the problems raised in the above background art.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A foundation construction method in house building construction, including the following steps:

[0008] Step 1: Geological exploration and site pre-treatment

[0009] Step 1.1: Use ground penetrating radar and drill sampling to analyze the soil layer distribution, groundwater level and the depth of the soft layer, and generate a three-dimensional geological model;

[0010] Step 1.2: Clean the site and lower the water level. Use large-diameter dewatering wells to lower the groundwater level to 1.5 m below the excavation surface to ensure a dry working environment;

[0011] Step 2: Treatment of shallow soft soil layers

[0012] Step 2.1: Replacement filling with construction waste. The construction waste is crushed to a particle size of ≤30 cm and admixed with 30%-35% silty clay to improve the gradation. It is backfilled in layers and compacted 8-10 times with a vibratory roller to form a replacement hard shell layer, which diffuses the load and reduces the additional stress of the underlying layer.

[0013] Step 3: Construction of deep composite pile foundation

[0014] Step 3.1: Drilling of combined pile foundation

[0015] A casing device combined with a steel pipe and an impact cone is used to drill in sections. The impact cone is connected to the steel pipe by threads. After the hole is drilled by the impact of the heavy hammer, the cone is retrieved by reverse rotation of the internal thread extraction rod to avoid repeated disassembly and assembly of the casing. After the impact cone is removed, the pile tip and pile body are constructed to complete the pile foundation construction.

[0016] Step 3.2: Selection of pile foundation type

[0017] Soft soil layer: Cement fly ash gravel piles are used.

[0018] Liquefied soil layer: A multi-pile type composite foundation of gravel piles and cement fly ash gravel piles is set up to eliminate the liquefaction effect.

[0019] Step 3.3: Construction of elastic shock-absorbing layer

[0020] An elastic concrete layer is laid between the pile top and the foundation. The material is composed of sodium silicate, sodium phosphate, slaked lime, and sand, forming an elastic concrete layer with a compressive strength of ≥60 MPa and a flexural strength 4 times that of the compressive strength to absorb the energy of seismic waves.

[0021] Step 4: Laying of composite cushion

[0022] A 30-cm-thick graded sand and gravel composite cushion is laid and compacted with a plate vibrator to ensure the joint bearing of the pile and soil.

[0023] Step 5: Integration of intelligent monitoring system

[0024] Optical fiber sensors and settlement monitoring points are buried to collect the data of foundation stress and settlement in real time, and the subsequent construction parameters are optimized through AI algorithms.

[0025] Step 6: Quality inspection and acceptance

[0026] The foundation performance is accepted by load plate test, CBR test and seismic wave simulation test.

[0027] Preferably, in the step 1, the diameter of the dewatering well is 0.5 m and the spacing is 15 m.

[0028] Preferably, in the step 2, the thickness of each backfill layer is 40 cm, and the total thickness of the replacement hard shell layer (1) is 1.2-1.8 m.

[0029] Preferably, in step 3.2, the pile diameter is 0.6 m, the pile length is 15 - 30 m, and the pile spacing is 2.5D, where D is the pile diameter.

[0030] Preferably, in step 3.3, the thickness of the elastic concrete layer is 0.4 - 0.6 m, where the water glass content is 5%, the sodium phosphate content is 1%, the hydrated lime content is 10%, the sand content is 40%, and the sand particle size is 2 mm.

[0031] Preferably, in step 4, the gravel and sand particle size of the composite cushion layer is 5 - 20 mm.

[0032] Preferably, in step 5, settlement points are made of threaded steel bars with a diameter of 20 mm. The top of the steel bars is 50 mm away from the original ground surface, buried in the casing, filled with fine sand and covered with cement mortar to ensure the stability of the measuring points.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The construction method of the present invention is more economical and environmentally friendly compared with the prior art, with a high utilization rate of construction waste, reduced lime consumption, reduced carbon emissions, and saved material costs;

[0035] (2) The seismic performance of the construction method of the present invention is improved. The elastic concrete layer improves the seismic intensity of the structure and increases the seismic energy absorption rate;

[0036] (3) The construction efficiency of the construction method of the present invention is improved. The casing hole-forming process reduces the equipment disassembly and assembly time, thus shortening the construction period;

[0037] (4) The construction method of the present invention has a wider adaptability and is applicable to various complex geological conditions such as collapsible loess, silty soil, and miscellaneous fill.

[0038] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will be readily apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the foundation profile structure of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] A foundation construction method in building construction, including the following steps:

[0042] Step 1: Geological exploration and site pretreatment

[0043] Step 1.1: Use ground-penetrating radar and borehole sampling to analyze the soil layer distribution, groundwater level and depth of soft layers, and generate a three-dimensional geological model;

[0044] Step 1.2: Clear the site and lower the water level: Use large-diameter dewatering wells to lower the groundwater level 1.5 m below the excavation surface to ensure a dry working environment;

[0045] Specifically, the diameter of the dewatering well is 0.5 m and the spacing is 15 m;

[0046] Step 2: Treatment of shallow soft soil layers

[0047] Step 2.1: Replace and fill with construction waste soil. Crush the construction waste soil (broken bricks, concrete blocks) to a particle size ≤ 30 cm, and incorporate 30%-35% silty clay to improve the gradation; Backfill in layers, and use a 20T vibratory roller to compact 8-10 times to form a replacement hard shell layer 1 to disperse the load and reduce the additional stress of the underlying layer;

[0048] Specifically, the thickness of each backfill layer is 40 cm, and the total thickness of the replacement hard shell layer 1 is 1.2-1.8 m;

[0049] Step 3: Construction of deep composite pile foundations

[0050] Step 3.1: Drilling holes for combined pile foundations

[0051] Use a casing device combined with a steel pipe and an impact cone to drill holes in sections. The impact cone is connected to the steel pipe by threads. After the hole is drilled by the heavy hammer impact, the cone is retrieved by reverse rotation of the internal thread extraction rod to avoid repeated disassembly and assembly of the casing; After removing the impact cone, carry out the construction of the pile end and pile body to complete the construction of pile foundation 2;

[0052] Step 3.2: Selection of pile foundation type

[0053] Soft soil layer: Use cement fly ash gravel piles. The diameter and length of pile foundation 2 are 0.6 m, the pile length is 15-30 m, and the pile spacing is 2.5D, where D is the pile diameter;

[0054] Liquefied soil layer: Set up a multi-pile type composite foundation of gravel piles and cement fly ash gravel piles to eliminate the liquefaction effect;

[0055] Step 3.3: Construction of elastic shock-absorbing layer

[0056] An elastic concrete layer (3) is laid between the pile top and the foundation. The material is composed of sodium silicate, sodium phosphate, slaked lime, and sand, forming an elastic concrete layer with a compressive strength ≥ 60 MPa and a flexural strength 4 times that of the compressive strength, which can absorb the energy of seismic waves.

[0057] Specifically, the elastic concrete layer 3 is 0.4 - 0.6 m thick, with a sodium silicate content of 5%, a sodium phosphate content of 1%, a slaked lime content of 10%, and a sand content of 40%. The sand has a particle size of 2 mm.

[0058] Step 4: Geocell Mattress and Intelligent Monitoring

[0059] Laying of the composite geocell mattress:

[0060] Lay a 30 - cm - thick graded sand - gravel geocell mattress 4 and compact it with a plate vibrator to ensure the combined bearing of the pile and soil.

[0061] Specifically, the sand and gravel of the composite geocell mattress 4 has a particle size of 5 - 20 mm.

[0062] Step 5: Integration of the Intelligent Monitoring System

[0063] Embed fiber - optic sensors and settlement monitoring points to collect foundation stress and settlement data in real - time, and optimize subsequent construction parameters such as the number of rolling passes and filler ratio through AI algorithms.

[0064] Specifically, use threaded steel bars with a diameter of 20 mm to make settlement points. The top of the steel bar is 50 mm from the original ground surface, buried in the casing, filled with fine sand and covered with cement mortar to ensure the stability of the measuring points.

[0065] Step 6: Quality Inspection and Acceptance

[0066] Adopt load plate tests, CBR tests, and seismic wave simulation tests to accept the foundation performance.

[0067] For the performance acceptance of the foundation after the construction of the building foundation, comprehensively adopt load plate tests, CBR tests, and seismic wave simulation tests to ensure that the foundation bearing capacity, deformation modulus, and seismic performance meet the design requirements. The following are the specific test plans and test results.

[0068] 1. Load Plate Test

[0069] Adopt a circular rigid bearing plate with a diameter of 0.5 m. The width of the foundation pit ≥ 1.5 m, and a 20 - mm - thick medium - coarse sand is laid at the base for leveling. The loading levels are divided into 8 levels, and the maximum loading amount is taken as 2 times the design value. After each level of loading, observe the settlement at time intervals of 10, 10, 10, 15, 15 min. When the settlement rate ≤ 0.1 mm / h for 2 consecutive hours, it is determined to be stable.

[0070] Termination condition: Obvious lateral extrusion of the soil around the bearing plate, sharp increase in settlement, and cumulative settlement s / bearing plate diameter b ≥ 0.06.

[0071] Bearing capacity calculation: Take the load value corresponding to the proportional limit of the p-s curve; when the number of test points in the same soil layer is ≥ 3 and the range is ≤ 30% of the average value, take the average value as the characteristic value of the bearing capacity.

[0072] Test results: The characteristic value of the bearing capacity is 180 kPa, meeting the design requirement of ≥ 150 kPa; the cumulative settlement is 15 mm, meeting the design requirement of ≤ 20 mm; the deformation modulus is 27.8 MPa, which is calculated by back-calculating the settlement and conforms to the design value of the sand-gravel cushion layer.

[0073] 2. CBR test

[0074] Take the graded sand-gravel cushion layer, compact it in layers according to the water content of 8% - 10%, and the thickness of each layer is ≤ 40 cm. Use a standard penetration sampler with a diameter of 50 mm, and the penetration rate is 1 mm / min. Record the pressure values at the penetration depths of 2.5 mm and 5.0 mm.

[0075] CBR value calculation:

[0076] According to the formula where P is the penetration pressure of the specimen, P0 is the penetration pressure of the standard crushed stone, and 7 MPa corresponds to 100%.

[0077] Test results: The CBR value is 10%, meeting the design requirement of ≥ 8%; the degree of compaction is 95%.

[0078] 3. Seismic wave simulation test

[0079] Use artificial seismic sources or shaking tables to simulate the input of seismic waves, and arrange acceleration sensors at the top and bottom of the elastic shock-absorbing layer to record the propagation parameters of seismic waves.

[0080] Test parameters:

[0081] Shear wave velocity (Vs): Measured by the cross-hole method or the surface wave method to calculate the dynamic shear modulus of the foundation;

[0082] Shock-absorbing efficiency: Compare the energy attenuation rate of the input and output waveforms.

[0083] where A is the peak acceleration.

[0084] Test results: The shear wave velocity is 250 m / s, indicating a relatively high degree of compaction of the foundation; the shock-absorbing efficiency is 45%, meeting the design requirement of ≥ 40%; the maximum acceleration attenuation is from the input of 0.3 g to the output of 0.165 g, meeting the requirements of the 8-degree seismic fortification.

[0085] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] In the present invention, unless otherwise clearly specified or limited, a first feature being "on" or "under" a second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, a first feature being "above", "over" and "on top of" a second feature may be that the first feature is directly above or obliquely above the second feature, or merely means that the first feature has a higher horizontal height than the second feature. A first feature being "under", "below" and "beneath" a second feature may be that the first feature is directly below or obliquely below the second feature, or merely means that the first feature has a lower horizontal height than the second feature.

[0087] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example" or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0088] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A foundation construction method in house building construction, characterized in that It includes the following steps: Step 1: Geological exploration and site pre-treatment Step 1.1: Use ground-penetrating radar and borehole sampling to analyze the soil layer distribution, groundwater level, and depth of soft layers, and generate a three-dimensional geological model; Step 1.2: Clean the site and dewater. Use large-diameter dewatering wells to lower the groundwater level 1.5 m below the excavation surface to ensure a dry working environment; Step 2: Treatment of shallow soft soil layers Step 2.1: Replace with construction waste. Crush the construction waste to a particle size ≤ 30 cm, and mix in 30%-35% silty clay to improve the gradation; backfill in layers, and compact with a vibratory roller 8-10 times to form a replacement hard crust layer (1), which spreads the load and reduces the additional stress on the underlying layer; Step 3: Construction of deep composite pile foundations Step 3.1: Combined pile foundation hole formation Use a casing device combined with a steel pipe and an impact cone to form holes in sections. The impact cone is connected to the steel pipe by threads. After the hole is formed by the impact of the heavy hammer, the cone is recovered by reverse rotation of the inner-thread extraction rod to avoid repeated disassembly and assembly of the casing; after the impact cone is removed, construction of the pile tip and pile body is carried out to complete the construction of the pile foundation (2); Step 3.2: Selection of pile foundation type Soft soil layer: Use cement fly ash gravel piles; Liquefied soil layer: Set up a multi-pile type composite foundation of gravel piles and cement fly ash gravel piles to eliminate the liquefaction effect; Step 3.3: Construction of the elastic shock-absorbing layer Lay an elastic concrete layer (3) between the pile top and the foundation. The material is composed of sodium silicate, sodium phosphate, slaked lime, and sand. Form an elastic concrete layer with a compressive strength ≥ 60 MPa and a flexural strength 4 times the compressive strength to absorb the energy of seismic waves; Step 4: Laying of the composite cushion Lay a 30-cm-thick graded sand and gravel composite cushion (4), and compact it with a plate vibrator to ensure the combined bearing of the pile and soil; Step 5: Integration of the intelligent monitoring system Install fiber optic sensors and settlement monitoring points, and collect foundation stress and settlement data in real time. Optimize subsequent construction parameters through AI algorithms; Step 6: Quality inspection and acceptance Use load plate tests, CBR tests, and seismic wave simulation tests to accept the foundation performance.

2. A foundation construction method in house building construction according to claim 1, characterized in that: In Step 1, the dewatering well has a diameter of 0.5 m and a spacing of 15 m.

3. A foundation construction method in building construction according to claim 1, characterized in that: In Step 2, the thickness of each backfill layer is 40 cm, and the total thickness of the replacement hard crust layer (1) is 1.2-1.8 m.

4. A foundation construction method in building construction according to claim 1, characterized in that: In Step 3.2, the pile foundation (2) has a diameter of 0.6 m, a length of 15-30 m, and a pile spacing of 2.5D, where D is the pile diameter.

5. A foundation construction method in house building construction according to claim 1, characterized in that: In Step 3.3, the elastic concrete layer (3) is 0.4-0.6 m thick, with a sodium silicate content of 5%, a sodium phosphate content of 1%, a slaked lime content of 10%, and a sand content of 40%. The sand particle size is 2 mm.

6. A foundation construction method in building construction according to claim 1, characterized in that: In Step 4, the gravel and sand in the composite cushion (4) have a particle size of 5-20 mm.

7. A foundation construction method in building construction according to claim 1, characterized in that: In Step 5, use 20-mm-diameter deformed steel bars to make settlement points. The top of the steel bar is 50 mm from the original ground surface, buried in the casing, filled with fine sand, and covered with cement mortar to ensure the stability of the measuring points.

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