Pile-soil integrated intelligent pile forming method based on energy accumulation and pressure-induced phase change

Abstract

The invention discloses a pile-soil integrated intelligent pile forming method based on energy accumulation and pressure-induced phase change. The pile-soil integrated intelligent pile forming method comprises the steps of in-situ sensing drilling, intelligent regulation and control to form plastic cement soil and an artificial supporting layer, and overload pressure-stabilizing pile pressing to synchronously complete penetration verification and pre-sedimentation. The method has the advantages of controllable quality, shortened construction period and reduced settlement, and is especially suitable for coastal seaside soil layer construction in the Middle East.

Description

Technical Field

[0001] This invention relates to an intelligent construction method for rigid composite piles. Background Technology

[0002] The characteristics of the soil layers along the Middle Eastern coast are as follows: ① There is a Sabkha soil layer with 60% water content and a depth greater than 4m; ② There are corrosive saline-alkali low-lying beaches; ③ There is a cemented dense sand layer at the bottom 7m to 20m with a weak underlying layer; the use of hammer-driven piles with varying bearing layers (single-section pipe piles pressed into high-density dense sand layers) is prone to cracking and corrosion by chloride and sulfate ions. Previously, it was difficult to construct with bored piles in high-density sand layers. Single pipe piles could not be welded, but the pressure could not be driven to the material's ultimate strength. Even if the pile driving force reached the ultimate bearing capacity (or the ultimate strength of the pipe pile material) during construction, the measured bearing capacity in the later static load test would be reduced to 70%.

[0003] The Persian Gulf region in the Middle East is characterized by the unique Sabkha geology, characterized by high water content, high salinity, high compressibility, and low bearing capacity, often overlain by dense, cemented sand layers with uneven strength. Traditional pile foundation technologies face severe challenges here: Drilled cast-in-place piles: drilling in dense sand layers is difficult, prone to borehole collapse and diameter reduction, the quality of sediment at the pile bottom is difficult to control, and a large amount of mud pollution is generated, resulting in long construction periods and high costs; Precast pipe piles: multi-section welded long piles have weak corrosion protection at the weld points and risks to integrity; hammer driving or static pressure driving piles are difficult to penetrate the undulating dense sand layers, and are prone to pile body cracking, accelerating chloride ion erosion. The pile tip is placed on uneven sand layers, making settlement control difficult; Conventional composite pile technology (such as the Japanese static drilling and rooting method): piles are planted in fluid cement-soil, where the cement-soil strength is low (usually 0.8-1.2 MPa), hardening shrinkage easily leads to loss of pile side friction, and the bearing capacity cannot be verified during construction.

[0004] In existing technologies, pile foundation construction and quality testing are separate processes. Survey reports have limitations, construction relies on experience, and the inspection of pile integrity and bearing capacity is a post-construction sampling inspection, which involves uncertainty and lag, like "blind men touching an elephant," making it impossible to achieve reliability and controllable settlement for each pile.

[0005] Therefore, there is an urgent need for a pile foundation technology that can proactively adapt to complex geology, directly complete core quality verification during construction, eliminate corrosion risks, and significantly improve efficiency and certainty. Summary of the Invention

[0006] The purpose of this invention is to provide an integrated intelligent pile-forming method based on energy accumulation and pressure-induced phase change, which integrates "geological exploration, soil improvement, pile formation, testing, and settlement pre-completion".

[0007] The present invention also aims to provide an intelligent pile-forming method based on energy accumulation and pressure-induced phase change, which is particularly suitable for construction in coastal soil layers in the Middle East.

[0008] The technical solution of this invention is: A pile-soil integrated intelligent pile-forming method based on energy accumulation and pressure-induced phase change is characterized by: in-situ sensing drilling → intelligent control to form plastic cement soil and artificial bearing layer → surcharge-stabilized pile driving, and simultaneous completion of penetration verification and pre-settlement. The in-situ sensing drilling employs heavy-duty, multi-functional, intelligent, digital, and information-based equipment. This equipment is equipped with a carbide drill bit, dry powder-spraying spiral blades, and wet-process blade-shaped mixing blades. High-speed mixing is used to penetrate the lower dense cemented sand layer. Based on the in-situ soil moisture content (w) measured by the drilling nuclear magnetic resonance sensor, the mixing mode is automatically selected: if w > 30%, a high-pressure air curtain splitting and drainage combined with dry powder injection mode is activated; if w < 20%, a water injection mixing mode is activated. During the mixing process, a reverse compressive force of no less than 80 tons is applied to the spiral blades to achieve diameter expansion and densification. The intelligent control system forms plastic cement soil and artificial bearing layer. Data is monitored in real time by pre-embedded sensors. Advanced drilling is carried out during the mixing construction to confirm the depth of the bearing layer. The future core pile length is predicted by single-section pipe piles in whole meters. The core is mixed to whole meters and then re-sprayed, re-mixed and re-pressed at the pile end to create an artificial high-strength mudstone bearing layer at the bottom.

[0009] During overload stabilizing pile driving, a single section of ultra-high strength pipe pile is driven into viscoelastic-plastic cement-soil. During the driving process, a 1260-type integrated intelligent static pressure pile driver with stabilizing penetration testing is used to control the pressure at 4000-10000 kN. The length of each pipe pile section is 10m-16m (UHC500 or UHC600 pipe piles with a wall thickness of 150-180mm, reinforced and thickened, with a driving force of 5000-10000 kN). The equivalent energy hammering method is used to drive ultra-high strength pipe piles. The last three rounds consist of ten blows each, with a penetration depth of no more than 30-50mm. The energy of each hammer blow (work done by the energy level) and its corresponding penetration depth (especially the settlement of sensitive parts of the bearing layer) are equivalent to the maximum energy high strain test performed under full-scale conditions in situ.

[0010] Within a window period of 2-10 hours after cement-soil mixing, the pipe piles are pressed to the design elevation, and a final stabilizing value F_final is applied. This F_final value must simultaneously satisfy: F_final ≥ k1 × design ultimate bearing capacity, and F_final ≤ k2 × ultimate compressive strength of the pipe pile material, where k1 ≥ 1.1 and k2 ≤ 0.85. Through this stabilizing process, the soil at the pile tip completes the main plastic settlement.

[0011] In response to the characteristics of the coastal soil in the Middle East, electromagnetically sensitive materials such as low-carbon, corrosion-resistant, dense, and slow-setting slag powder, nano-silica powder, fly ash, or polyacrylamide are added to the cement-soil during the construction of rigid composite piles, accounting for 0.01%-5% by mass, to form intelligent cement-soil that can be activated and responded to.

[0012] During the construction of cement-soil piles, cement powder is sprayed onto the pile top and then sprayed, stirred, and compacted again at the pile bottom to create an artificial high-strength mudstone bearing layer. Then, ultra-high-strength pipe piles are driven in, forming a 3-5 meter artificial bearing layer. By increasing the cement powder content and repeating the spraying, stirring, and compaction, a high-strength, high-density cement-soil bearing layer is formed. Overload preloading is applied to the pile tip to achieve initial strength cement-soil pre-consolidation and pre-settlement. Overload stabilization is then performed, with each 10-15m ultra-high-strength thick-walled pipe pile reaching a stabilization value exceeding its ultimate bearing capacity. This stabilization is repeated three times for more than 3 minutes, squeezing and expanding the plastic cement-soil on the pile side, leading to rapid hardening at the pile tip through preloading and pre-settlement, forming an overload stabilization system at the pile tip. During construction, bearing capacity testing, pile integrity and cement-soil properties verification, and dense cemented sand bearing layer verification are conducted. Pile tip settlement is then completed.

[0013] During in-situ sensing drilling, the current, torque, and depth data are monitored in real time as the equipment descends, forming a "current-depth" curve. This allows for immediate verification of geological reports, accurate identification of the interface and properties between soft soil layers and the bearing layer at the pile tip, and enables advanced drilling and geological verification. If the length of a single pipe pile exceeds 16m and the natural bearing layer has not yet been reached, re-spraying, re-stirring, and re-pressurizing are carried out from 3 meters above the pile tip to 5 meters below, artificially and directionally enhanced bearing layer. In-situ material design and treatment: Optimal moisture content control is carried out by dry powder spraying (when moisture content is >30%) or wet water spraying (when moisture content is <20%) to adjust the in-situ soil-cement mixture to achieve the optimal moisture content (12%-20%) and maximum dry density.

[0014] Adaptive design for complex geology: Long and short pile design: Based on geological undulations (changes in bearing stratum elevation), single-section pipe piles of varying lengths (10-15m) are used to form a "long and short pile" pattern. Short piles handle shallow bearing capacity, while long piles control deep settlement, avoiding welding. Corrosion and durability design: Cement-soil anti-corrosion isolation layer: High-density, low-permeability cement-soil piles formed using dry methods create a physical anti-corrosion barrier enveloping the pipe piles, forming a high-density, high-strength, corrosion-resistant, and seepage-proof "thick wall." The "long and short pile" pattern consists of 10-40% longer composite piles and the remaining shorter composite piles. The longer piles penetrate deeper or more stable natural bearing strata to control settlement, while the shorter piles are anchored to artificial bearing strata to bear the main load. All piles are surrounded by cement-soil layers that overlap in planar projection to form a grid-like whole.

[0015] Two energy inputs and verifications: First: The mechanical shear energy and counterpressure of the mixing pile machine achieve soil improvement and initial cement-soil shaping, and the improvement effect is verified by current data; Second: The overload pressing force of the stabilizing pile machine performs secondary compaction of the cement-soil, and its final quality is directly verified by the pile driving curve; Pressure-induced phase transformation into rock: The above huge energy input creates a high temperature, high pressure and high humidity environment around the pile, driving the cement-soil to undergo "pressure-induced phase transformation", rapidly transforming from a plastic body into a rock-like body with a strength of 10-30MPa, achieving "elastic enhancement".

[0016] The “MEII” four-element coupling model is established, namely the material-energy-information-intelligent regulation four-element coupling model. Specifically, it includes: in-situ sensing drilling, intelligent regulation during the formation of plastic cement soil and artificial bearing layer, and during the mixing and reinforcement of the drill rod during the lifting, the system executes a differentiated mixing strategy based on the real-time inverted water content data of each soil layer. The core objective is to avoid the various drawbacks caused by high water-cement ratio. For soil layers with high water content: activate the "dry method-split drainage" mode; first, high-pressure air is sprayed through the hollow channel of the drill rod to split the soil and form a drainage network. Then, a high amount of composite cementitious dry powder is sprayed in. The dry powder quickly absorbs the free water in the soil, so that the soil changes from a fluid plastic state to the optimal water content state, forming a dense plastic cement soil.

[0017] For soil layers with low moisture content: activate the "wet method - humidification mixing" mode and spray water to ensure that the cementitious material is fully hydrated; Targeted reinforcement at the pile tip: Within the pre-set pile tip and the area from 3 meters above to 5 meters below, the system instructs the drilling rig to perform a "re-jetting, re-mixing, and back pressure" reinforcement process; by significantly increasing the amount of cementitious material and applying huge downward mechanical back pressure, the in-situ soil and cementitious material in this area are forcibly mixed and compacted, ultimately forming an "artificial mudstone bearing layer" with a diameter of not less than 1000 mm, an unconfined compressive strength of not less than 10 MPa, and extremely low permeability.

[0018] This invention avoids the "bias-interference" of indoor geotechnical tests, providing accurate, precise, reliable, and demanding in-situ testing, exploration, and geophysical exploration functions. Through bearing layer reconstruction and surcharge preloading: at the pile tip depth, by increasing the cement content and re-stressing, a locally reinforced "artificial mudstone bearing layer" is actively formed. Subsequently, surcharge stabilization is achieved using a pile driving force matching the ultimate strength of the pipe pile (e.g., 9000 kN). This process simultaneously accomplishes three things: 1. Bearing capacity verification: The bearing capacity of a single pile was verified using ultimate load.

[0019] 2. Pile tip pre-settlement: Under high stress, the soil at the pile tip is compacted, completing most of the post-construction settlement ahead of schedule.

[0020] 3. Promoted diagenesis: The combined effect of high pressure and cement hydration heat promotes the rapid diagenesis of low-carbon cementitious materials (such as geopolymers containing slag powder) under high temperature, high pressure and high humidity conditions, forming high-strength piles.

[0021] This invention combines high-power mixing (2×110-160kW) with in-situ exploration capabilities. Its carbide drill bit and auger blades are not only construction tools but also sensors for sensing while drilling. By monitoring parameters such as drilling pressure, torque, and rotational speed, it can invert the mechanical properties of the soil layer (such as the cementation strength of dense sand layers) in real time, equivalent to "advanced drilling." During construction, the depth of the bearing stratum can be confirmed instantly, and the length of the precast core pile can be determined in whole meters.

[0022] An integrated overload stabilization and penetration testing machine, a 1260-ton intelligent pile driver, is used. When driving ultra-high strength pipe piles (such as UHC600), the applied pile driving force of 4000-10000 kN versus depth curve is itself a continuous in-situ full-scale static penetration test (CPT) curve, which can verify the strength distribution of the plastic cement soil around the pile.

[0023] Multi-parameter fusion sensing: The system integrates real-time monitoring of multiple parameters such as current, torque, water-cement ratio, pile driving force, and acoustic waves. This serves not only as a construction record but also as a basis for quality control and verification. For example, a sudden change in mixing current can indicate entry into a dense sand layer; the pile driving force curve can determine whether the pile tip has reached the artificial bearing layer.

[0024] Targeted feedback control: Real-time adjustment of the process based on sensing data. For example, based on the monitored moisture content, the process dynamically selects wet spraying softening (low moisture content - high spraying torque and current value reaching the limit - such as 400A) and dry spraying / split drainage (high moisture content); "re-spraying, re-mixing and re-pressing" is carried out at the pile end to create a high-strength cement-soil bearing layer.

[0025] The advantages of this invention also include: 1. Quality and Reliability Revolution: Transforming the traditional "post-construction spot check" into "100% full inspection during construction", with the inspection standard being the most stringent ultimate load state, resulting in extremely high certainty of pile foundation quality.

[0026] 2. Settlement control revolution: It advances the completion of post-construction settlement to the construction period, fundamentally solving the settlement risks of soft soil and uneven foundations. It is especially suitable for large storage tanks, precision factories and other structures that are sensitive to settlement.

[0027] 3. Breakthrough in corrosion prevention and durability: The use of single-section weld-free thick-walled UHC pipe piles eliminates weak points in welding corrosion; the high-density cement soil (which can be mixed with corrosion inhibitors) formed by the surrounding rock forms an excellent protective layer, greatly improving the overall corrosion resistance.

[0028] 4. Green, low-carbon, and efficient: Utilizing in-situ soil as the main aggregate significantly reduces sand and gravel mining and transportation; the process requires no slurry, making it environmentally friendly; integrated construction and testing shorten the construction period by 30%-50%. The use of magnesium-based cementitious materials can further achieve a negative carbon effect.

[0029] 5. Strong geological adaptability: Specifically designed for the complex geology of the Middle East, characterized by high salinity, high water content, and alternating layers of soft and hard soil, it provides a systematic solution for dynamic regulation and targeted reinforcement.

[0030] The present invention will be further described below with reference to the embodiments. Detailed Implementation

[0031] A pile-soil integrated intelligent pile-forming method based on energy accumulation and pressure-induced phase change includes: in-situ sensing drilling → intelligent control to form plastic cement soil and artificial bearing layer → surcharge-stabilized pile driving, and simultaneous completion of penetration verification and pre-settlement; The in-situ sensing drilling employs heavy-duty (2×110kw-160kw) multi-functional intelligent digital information equipment. This equipment is equipped with a carbide drill bit, dry powder injection spiral blades, and wet blade mixing blades. It enters the lower dense cemented sand layer through high-speed mixing. Based on the in-situ soil moisture content w measured by the drilling nuclear magnetic resonance sensor, the mixing mode is automatically selected: if w>30%, the high-pressure air curtain splitting drainage combined with dry powder injection mode is activated; if w<20%, the water injection mixing mode is activated. During the mixing process, diameter expansion and densification are achieved by applying a reverse extrusion force of not less than 80 tons to the spiral blades. The intelligent control forms plastic cement soil and artificial bearing layer. Data is monitored in real time through pre-embedded sensors. Advanced drilling is carried out during the mixing construction to confirm the depth of the bearing layer. The future core pile length is predicted by single-section pipe piles in whole meters. The core is mixed to whole meters and then re-sprayed, re-mixed and re-pressed at the pile end to create an artificial high-strength mudstone bearing layer at the bottom. During overload stabilizing pile driving, a single section of ultra-high strength pipe pile is driven into viscoelastic-plastic cement-soil. During the driving process, a 1260-type integrated intelligent static pressure pile driver with stabilizing penetration testing is used to control the pressure at 4000-10000 kN. The length of each pipe pile section is 10m-16m (UHC500 or UHC600 pipe piles with a wall thickness of 150-180mm, reinforced and thickened, with a driving force of 5000-10000 kN). The equivalent energy hammering method is used to drive ultra-high strength pipe piles. The last three rounds consist of ten blows each, with a penetration depth of no more than 30-50mm. The energy of each hammer blow (work done by the energy level) and its corresponding penetration depth (especially the settlement of sensitive parts of the bearing layer) are equivalent to the maximum energy high strain test performed under full-scale conditions in situ.

[0032] Within a window period of 2-10 hours after cement-soil mixing, the pipe piles are pressed to the design elevation, and a final stabilizing value F_final is applied. This F_final value must simultaneously satisfy: F_final ≥ k1 × design ultimate bearing capacity, and F_final ≤ k2 × ultimate compressive strength of the pipe pile material, where k1 ≥ 1.1 and k2 ≤ 0.85. Through this stabilizing process, the soil at the pile tip completes the main plastic settlement.

[0033] In response to the characteristics of the coastal soil in the Middle East, electromagnetically sensitive materials such as low-carbon, corrosion-resistant, dense, and slow-setting slag powder, nano-silica powder, fly ash, or polyacrylamide are added to the cement-soil during the construction of rigid composite piles, accounting for 0.01%-5% by mass, to form intelligent cement-soil that can be activated and responded to.

[0034] During the construction of cement-soil piles, cement powder is sprayed onto the pile top and then sprayed, stirred, and compacted again at the pile bottom to create an artificial high-strength mudstone bearing layer. Then, ultra-high-strength pipe piles are driven in, forming a 3-5 meter artificial bearing layer. By increasing the cement powder content and repeating the spraying, stirring, and compaction, a high-strength, high-density cement-soil bearing layer is formed. Overload preloading is applied to the pile tip to achieve initial strength cement-soil pre-consolidation and pre-settlement. Overload stabilization is then performed, with each 10-15m ultra-high-strength thick-walled pipe pile reaching a stabilization value exceeding its ultimate bearing capacity. This stabilization is repeated three times for more than 3 minutes, squeezing and expanding the plastic cement-soil on the pile side, leading to rapid hardening at the pile tip through preloading and pre-settlement, forming an overload stabilization system at the pile tip. During construction, bearing capacity testing, pile integrity and cement-soil properties verification, and dense cemented sand bearing layer verification are conducted. Pile tip settlement is then completed.

[0035] When using a low water-cement ratio and low moisture content dry-wet mixing method with layer-by-layer counter-pressure, if cement powder is not sprayed on the pile top, pile slippage is likely to occur during pile driving, resulting in insignificant pile side compaction and reduced side friction. If wet construction is used or in areas with high moisture content, drainage and dewatering measures and the addition of cement powder are not taken, the upper soft soil layer will lack restraint or lateral resistance.

[0036] When using a single-section precast pile as the core, the integrity of the pile body does not need to be inspected (the single-section pipe pile has no welded joint and does not require anti-corrosion treatment). The overload stabilization limit value of the pile end (such as UHC500(150) matching 9000 kN pile driving force, UHC600(180) matching 10000 kN pile driving force), during construction, the overload stabilization bearing layer preload pile end soil pre-settlement, hardening pre-rock formation, over-consolidation, cement soil pressure phase transformation extrusion and densification rapid rock formation, the later cement soil plastic state pile driving force increases by 1.5-3.0 times, and continues to increase in the later stage, the stabilization value matches the strength bearing capacity limit value of the single-section ultra-high strength pipe pile material.

[0037] In the Gulf region, bored piles are currently being driven to a depth of 20-30 meters because of the underlying sand layer. The elevation, strength, and degree of cementation of this sand layer vary; in some areas, the SPT (Standard Penetration Test) blow count is 50-100, while in others it's only 35-45. Driving two sections of pipe piles would require welding, and it's difficult to drive them down the same height. This invention utilizes an artificial magnetic layer to directly achieve the ultimate bearing capacity. This ultimate bearing capacity is achieved by completing the settlement and ensuring the pile tip settlement is stable.

[0038] During in-situ sensing drilling, the current, torque, and depth data are monitored in real time during the equipment's descent to form a "current-depth" curve, which verifies the geological report in an instant and accurately identifies the interface and properties between the weak soil layer and the bearing layer at the pile tip, enabling advanced drilling and geological verification. If the length of a single pipe pile exceeds 16m and the natural bearing layer has not yet been reached, the pile tip is subjected to re-spraying, re-stirring, and re-pressurizing from 3 meters above to 5 meters below the pile tip to artificially and directionally reinforce the bearing layer.

[0039] In-situ material design and treatment: Optimal moisture content control is carried out by dry powder spraying (when moisture content is >30%) or wet water spraying (when moisture content is <20%) to adjust the in-situ soil-cement mixture to achieve the optimal moisture content (12%-20%) and maximum dry density.

[0040] Adaptive design for complex geology: Long and short pile design: Based on geological undulations (changes in bearing stratum elevation), single-section pipe piles of varying lengths (10-15m) are used to form a "long and short pile" pattern. Short piles handle shallow bearing capacity, while long piles control deep settlement, avoiding welding. Corrosion and durability design: Cement-soil anti-corrosion isolation layer: High-density, low-permeability cement-soil piles formed using dry methods create a physical anti-corrosion barrier enveloping the pipe piles, forming a high-density, high-strength, corrosion-resistant, and seepage-proof "thick wall." The "long and short pile" pattern consists of 10-40% longer composite piles and the remaining shorter composite piles. The longer piles penetrate deeper or more stable natural bearing strata to control settlement, while the shorter piles are anchored to artificial bearing strata to bear the main load. All piles are surrounded by cement-soil layers that overlap in planar projection to form a grid-like whole.

[0041] Two energy inputs and verifications: First: The mechanical shear energy and counterpressure of the mixing pile machine achieve soil improvement and initial cement-soil shaping, and the improvement effect is verified by current data; Second: The overload pressing force of the stabilizing pile machine performs secondary compaction of the cement-soil, and its final quality is directly verified by the pile driving curve; Pressure-induced phase transformation into rock: The above huge energy input creates a high temperature, high pressure and high humidity environment around the pile, driving the cement-soil to undergo "pressure-induced phase transformation", rapidly transforming from a plastic body into a rock-like body with a strength of 10-30MPa, achieving "elastic enhancement".

[0042] The “MEII” four-element coupling model is established, namely the material-energy-information-intelligent regulation four-element coupling model. Specifically, it includes: in-situ sensing drilling, intelligent regulation during the formation of plastic cement soil and artificial bearing layer, and during the mixing and reinforcement of the drill rod during the lifting, the system executes a differentiated mixing strategy based on the real-time inverted water content data of each soil layer. The core objective is to avoid the various drawbacks caused by high water-cement ratio. For soil layers with high water content (ω > 30%, such as Sabkha soil): the "dry-split drainage" mode is activated; firstly, high-pressure air is injected through the hollow channel of the drill rod to split the soil and form a drainage network, and then a high-volume composite cementitious material dry powder (containing cement, slag powder, fly ash, polyacrylamide, etc.) is injected. The dry powder quickly absorbs the free water in the soil, causing the soil to change from a fluid plastic state to the optimal water content state (water-cement ratio W / C controlled at 0-0.4), forming a dense plastic cement soil; this fundamentally eliminates the risks of wet grout overflow, soil softening, and subsequent "pile slippage".

[0043] For soil layers with low moisture content (ω < 20%): Activate the "wet method - humidification and mixing" mode and spray water to ensure that the cementitious material is fully hydrated; Targeted reinforcement at the pile tip: Within a pre-defined area of ​​3 meters above and 5 meters below the pile tip, the system instructs the drilling rig to perform a "re-jetting, re-mixing, and back-pressure" reinforcement process. By significantly increasing the amount of cementitious material and applying enormous downward mechanical back pressure (up to tens to hundreds of tons), the in-situ soil and cementitious material in this area are forcibly mixed and compacted, ultimately forming an "artificial mudstone bearing layer" with a diameter of not less than 1000 mm, an unconfined compressive strength of not less than 10 MPa (up to 10-30 MPa), and extremely low permeability. This layer not only provides highly reliable end support, but its dense structure also constitutes an integrated "permanent anti-corrosion coat" that wraps around the subsequently implanted pipe pile.

[0044] This invention relates to a method and system for the construction and real-time testing of high-strength composite piles suitable for special geological conditions such as Sabkha in the Middle East coastal region. The core principle is "construction is investigation, pile completion is acceptance." First, heavy-duty intelligent mixing equipment with integrated investigation functions is used to simultaneously complete geological verification, bearing stratum positioning, and in-situ soil improvement while forming large-diameter cement-soil piles, and to create a high-strength artificial mudstone bearing stratum at the lower level. Then, within the optimal plasticity window of the cement-soil initial setting, a large-tonnage intelligent static pressure device is used to drive in single-section ultra-high-strength thick-walled pipe piles at a stable pressure value (e.g., 6000-10000 kN) matching the material's ultimate strength. This pile driving process simultaneously completes four key functions: 1) secondary compaction and reinforcement of the plastic cement-soil pile body; 2) overload preloading of the artificial bearing stratum at the pile tip, forcing post-construction settlement to occur during construction; 3) the stable pressure value itself serves as a verification test of the ultimate bearing capacity under the most demanding conditions; and 4) quality traceability and intelligent control are achieved through monitoring data streams such as current, torque, and pressure throughout the entire process. This invention abandons the traditional method of welding long piles and post-construction inspection, and solves the core pain points of pile foundation corrosion, uncontrollable settlement, and low construction efficiency in the high-salt, high-water, and soft-hard interlayered geology of the Middle East. It realizes low-carbon, high-efficiency, high-reliability, and digital delivery of pile foundation engineering.

Claims

1. A pile-soil integration intelligent pile-forming method based on energy accumulation and pressure-induced phase transition, characterized in that: Comprise: In-situ sensing drilling → intelligent regulation to form plastic cement soil and artificial bearing stratum → overloading pressure pile, synchronous completion of sounding verification and pre-settlement; The in-situ sensing drilling adopts heavy-duty multifunctional intelligent digital information equipment; the heavy-duty multifunctional intelligent digital information equipment is provided with a hard alloy drill bit, a dry method powder spraying spiral blade and a wet method blade stirring blade, enters the lower dense cementation sand layer through high-speed stirring, automatically selects a stirring mode according to the in-situ soil moisture content w measured by a nuclear magnetic resonance sensor while drilling: if w>30%, a high-pressure air curtain splitting and drainage combined dry powder spraying mode is started; if w<20%, a water injection stirring mode is started; during the stirring process, the diameter is expanded and densification is achieved by applying a reverse extrusion force of not less than 80 tons on the spiral blade; The intelligent regulation to form plastic cement soil and artificial bearing stratum, through real-time monitoring data by pre-embedded sensors, advanced drilling in the stirring construction, confirms the bearing stratum depth, predicts and determines the future core pile length by the whole meter number single-section pipe pile, stirs to the whole meter number and re-sprays, re-stirs and re-presses at the pile end, and creates an artificial high-strength mudstone bearing stratum in the lower part.

2. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile-forming method according to claim 1, characterized in that: When overloading pressure pile, the single-section super-high-strength pipe pile is extruded into viscoelastic plastic cement soil, and the pressure is controlled at 4000-10000 kN by a 1260 type pressure sounding detection integrated intelligent static pressure pile machine in the extrusion process; the single-section pipe pile length is 10-16 m; The super-high-strength pipe pile is hammered into by an equivalent energy hammering method, the last three arrays, each array ten times, the penetration degree is not more than 30-50 mm; In the window period of 2-10 hours after the cement soil is mixed, the pipe pile is pressed to the design elevation, and a final stable pressure value F_final is applied; the F_final value must meet the following conditions at the same time: F_final ≥ k1 × design ultimate bearing capacity, and F_final ≤ k2 × pipe pile material ultimate compressive strength, wherein k1 ≥ 1.1, k2 ≤ 0.85; through the stable pressure process, the soil at the pile end completes the main plastic settlement.

3. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile forming method according to claim 1 or 2, characterized in that: In view of the characteristics of the coastal soil layer in the Middle East, during the construction of the stiff composite pile, the low-carbon anticorrosive and dense retarding slag powder, nano silicon powder, fly ash or polyacrylamide electromagnetic sensitive material is added in the cement soil, the mass ratio is 0.01%-5%, forming the intelligent cement soil which can be excited and responded.

4. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile forming method according to claim 1 or 2, characterized in that During the construction of the cement soil pile, the cement powder is sprayed at the top of the pile, and re-sprayed, re-stirred and re-pressed at the bottom of the pile, creating an artificial high-strength mudstone bearing stratum in the lower part; then the super-high-strength pipe pile is pressed in, forming a 3-5 m artificial bearing stratum, increasing the cement powder content for re-spraying, re-stirring and re-pressing, forming a high-strength and high-density cement soil bearing stratum in the lower part, pre-consolidation and pre-settlement of the cement soil at the pile end with preliminary strength, overloading and pressure, three times of stable pressure of the single-section 10-15 m super-high-strength thick-walled pipe pile to the stable pressure value above the ultimate bearing capacity, the time is greater than 3 minutes, the extruded and densified plastic cement soil on the side of the pile, directly to the pre-pressing and pre-settlement of the pile end, rapid hardening, forming the overloading and pressure system at the pile end; during the construction process, the bearing capacity detection, pile body integrity and cement soil property verification, dense cementation sand stratum bearing stratum verification, and pile end settlement completion are carried out.

5. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile forming method according to claim 1 or 2, characterized in that: In-situ sensing drilling, by monitoring current, torque and depth data in real time during equipment descending, forms current-depth curve, verifies geological report in real time, accurately identifies interface and properties of soft soil layer and pile end bearing stratum, realizes advanced drilling and geological verification; if exceeding 16m of single-section pipe pile length, still not reaching natural bearing stratum, carries out re-spraying, re-agitating and re-pressing in 3m upper part to 5m lower part of pipe pile end, forms artificially directional targeted enhanced bearing stratum; In-situ material design and treatment: carries out optimal water content control, through dry method powder spraying or wet method water spraying regulation, makes in-situ soil-cement mixture reach optimal water content and maximum dry density.

6. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile forming method according to claim 1 or 2, characterized in that: Adaptive design for complex geology: long and short pile design: according to stratum fluctuation, adopts single-section pipe piles with different lengths, forms long and short pile pattern, short pile treats shallow bearing capacity, long pile controls deep settlement, avoids welding; anticorrosion and durability design: cement-soil anticorrosion isolation layer: high density low permeability cement-soil pile body formed by dry method forming, forms physical anticorrosion barrier wrapping pipe pile, namely forms high density, high strength, anticorrosion and anti-seepage "thick wall"; The long and short pile pattern is composed of 10-40% of longer composite piles and the rest of shorter composite piles, wherein the long pile end enters deeper or more stable natural bearing stratum to control settlement, the short pile end is anchored to artificial bearing stratum to bear main load, and the peripheral cement-soil of all piles overlaps each other in planar projection to form grid-shaped whole.

7. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile forming method according to claim 1 or 2, characterized in that: Two times of energy input and verification: first time: mechanical shearing energy and counter pressure of agitator pile machine, realizes soil improvement and preliminary cement-soil forming, and verifies improvement effect through current data; second time: overloading pressure input force of stabilizing pile machine, carries out secondary extrusion compaction of cement-soil, and directly verifies its final quality through pile pressing curve; pressure-induced phase change into rock: the above huge energy input creates high temperature, high pressure and high humidity environment around pile, drives cement-soil to have "pressure-induced phase change", rapidly transforms from plastic body to rock-like body with strength of 10-30MPa, realizes "elasticity enhancement".

8. The energy accumulation and pressure-induced phase change based pile-soil integrated intelligent pile forming method according to claim 1 or 2, characterized in that: Establishes "M-E-I-I" four-element coupling model, namely material-energy-information-intelligent control four-element coupling model, specifically including: in-situ sensing drilling, when forming plastic cement-soil and artificial bearing stratum, during agitating and reinforcing in drill rod lifting, the system executes differentiated agitating strategy according to real-time inversion of each soil layer water content data, core target is to avoid various disadvantages brought by high water-cement ratio: For high water content soil layer: starts "dry method-splitting drainage" mode; first splits soil through high pressure air jetting in drill rod hollow channel, forms drainage network, then sprays high content composite cementitious material dry powder, dry powder rapidly absorbs free water in soil, makes soil change from flow plastic state to optimal water content state, forms dense plastic cement-soil; For low water content soil layer: starts "wet method-humidifying agitating" mode, sprays water to ensure cementitious material fully hydrates; Pile end target reinforcement: within the preset range of 3 meters above and 5 meters below the pile end of the pipe pile, the system instructs the drilling machine to perform the "re-spraying, re-stirring, and counter-pressure" reinforcement process; by significantly increasing the cementitious material content and applying a large downward mechanical counter-pressure, the in-situ soil and cementitious material in this area are forcibly stirred and extruded to be compacted, ultimately forming a "man-made mudstone bearing layer" with a diameter of not less than 1000 mm, an unconfined compressive strength of not less than 10 MPa, and extremely low permeability.