Civil engineering foundation pit protection support construction method

Abstract

The invention provides a civil engineering foundation pit protection support construction method, which belongs to the technical field of civil engineering construction, and comprises the following steps: arranging drainage assemblies with detection heads at the periphery of a foundation pit, synchronously starting a vacuum preloading system, and inserting grouting pipelines in gaps of the drainage assemblies to implement graded grouting reinforcement; a rotary drilling rig is adopted for drilling and pile planting at intervals, and liquid slurry is injected into gaps between the piles after pile bodies are poured and formed; the foundation pit is excavated in a layered mode, supporting profile steel is installed after excavation of each layer is completed, and displacement monitoring devices and crack monitoring devices are evenly distributed on the periphery of the enclosure wall and the periphery of the foundation pit; and after foundation pit construction is completed, generated waste is used as recycled aggregate for backfilling. According to the civil engineering foundation pit protection supporting construction method, multiple steps are coordinated and linked, the traditional cutting procedure is integrated into an organic whole, the soil body and construction changes are dynamically adapted, the safety and stability of foundation pit supporting are improved, the construction period is shortened, and the material consumption and the environmental protection cost are reduced.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering construction technology, and more specifically, relates to a construction method for the protection and support of civil engineering foundation pits. Background Technology

[0002] Foundation pit protection and support is a core guarantee for construction safety, especially crucial in complex conditions such as soft soil foundations, high groundwater levels, and proximity to sensitive buildings and structures. However, traditional construction methods suffer from significant problems such as fragmented processes and delayed response, making them unsuitable for modern engineering needs. Currently, in the soil pretreatment stage, the linear process of investigation followed by reinforcement leads to delays in process connections, making soft soil prone to initial deformation; preloading and grouting parameters are set based on experience, failing to dynamically adapt to changes in soil data, often resulting in insufficient or excessive reinforcement; furthermore, the coordination between support installation and monitoring in foundation pit support is lacking, on-site connections are time-consuming, graded pressurization and stress monitoring are disconnected, stress loss rates are high, and later adjustments rely on manual intervention, resulting in delayed responses to anomalies and potential loss of control due to wireless interruptions. These problems make it difficult to connect the various steps of foundation pit support, failing to meet the requirements for foundation pit support. Summary of the Invention

[0003] The purpose of this invention is to provide a construction method for the protection and support of civil engineering foundation pits, so as to solve the technical problem that the multiple steps in the foundation pit support in the prior art are difficult to connect and cannot meet the requirements of foundation pit support.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a construction method for the protection and support of civil engineering foundation pits, comprising: S1: Install drainage components with probes around the foundation pit and collect soil data; simultaneously start the vacuum preloading system, adjust the negative pressure value according to the soil data, and insert grouting pipes in the gaps of the drainage components to carry out graded grouting reinforcement until the monitored soil data tends to stabilize and then stop preloading. S2: Rotary drilling rigs are used to drill holes and install piles at intervals. After the piles are cast and formed, liquid grout is injected into the gaps between the piles. During the grouting process, the leakage between the piles is monitored in real time to adjust the grouting pressure and form a continuous water-stopping retaining wall. S3: Excavate the foundation pit in layers. After each layer is excavated, install supporting steel. Use a top pressure device to apply pressure to the supporting steel in stages. At the same time, install stress sensors to provide feedback data and correct the pressure value. S4: Displacement monitoring devices and crack monitoring devices are installed around the retaining wall and the foundation pit. When the monitoring data of the displacement monitoring device and the crack monitoring device exceeds the threshold, the pressure regulator is activated to replenish or release pressure. S5: After the foundation pit construction is completed, the waste generated in steps S1-S4 is used as recycled aggregate for backfilling.

[0005] In one possible implementation, in S1, the drainage component is connected to the vacuum preloading system and the grouting pipeline. The soil data collected by the probe generates a real-time preloading and grouting linkage command. When the moisture content in the soil data is higher than a preset range, the negative pressure value of the vacuum preloading system is increased to accelerate drainage. When the cohesion in the soil data is lower than a threshold, the grouting pipeline is automatically triggered to perform grouting reinforcement, so as to achieve adaptive reinforcement driven by both moisture content and cohesion.

[0006] In one possible implementation, in S1, the drainage components are set up according to the division of the foundation pit area. The drainage component of each foundation pit area is connected to an independent vacuum preloading control valve. The probe collects data of each foundation pit area and transmits it to the vacuum preloading system. Based on the soil data, potential risk areas in the foundation pit are identified, and grout is injected into the potential risk areas first. After the grout solidifies to form a closed isolation shell, conventional grouting is carried out to implement graded grouting. After the preloading is completed, a trench is excavated outside the excavation edge of the foundation pit, and the trench is filled with graded sand and gravel to form a stress relief trench.

[0007] In one possible implementation, the drainage component further includes a geological stratification correction module, which automatically adjusts the weighting coefficients of moisture content and cohesion when the probe detects that the soil has entered different geological strata.

[0008] In one possible implementation, in S2, a leakage monitoring device is arranged to monitor leakage parameters between piles. A guide pipe is connected between the leakage monitoring device and the grouting pipeline. An automatic control valve is provided on the guide pipe. When the leakage monitoring device detects a leakage signal, the automatic control valve opens, guiding the grout in the grouting pipeline to flow through the guide pipe to the leakage point.

[0009] In one possible implementation, in S2, annular grouting channels are set at preset intervals along the depth direction of the retaining wall, and the grouting channels are connected to the grouting pipes of each pile body; when monitoring detects local water-stopping failure, repair grout is injected into the corresponding grouting channel through the ground interface, achieving deep water-stopping repair without excavation.

[0010] In one possible implementation, a stress-compensating joint is installed in the foundation pit to install supporting steel. The stress-compensating joint is used to release elastic potential energy to compensate for displacement when the supporting steel is deformed under stress. The exposure time of the foundation pit excavation surface is monitored in real time. If the exposure time exceeds the preset time, the interval of staged pressurization is shortened to reduce soil stress loss.

[0011] In one possible implementation, a control terminal is also provided in S4. The control terminal includes a multi-source data verification module. The multi-source data verification module receives the readings of the displacement monitoring device and the crack monitoring device, the recognition results of the surface image taken by the UAV, and the monitoring data of the adjacent monitoring points, and determines whether the monitoring data is valid after performing a consistency comparison.

[0012] In one possible implementation, in S5, the recycled aggregate includes mixing demolition waste with waste industrial solid waste, spraying an active activator onto the mixture, and enhancing the activity of the aggregate through a chemical reaction between the active activator and the solid waste; the backfilling of the recycled aggregate is carried out in conjunction with the construction of the waterproof layer, and when backfilling to the preset position at the bottom of the waterproof layer, the aggregate is manually spread, and modified asphalt emulsion is injected into the aggregate. After the emulsion penetrates the gaps between the aggregates to form a sealing layer, subsequent backfilling is carried out.

[0013] In one possible implementation, in S1, the drainage assembly includes a hollow sleeve and a one-way valve installed on the hollow sleeve, and the probe is detachably connected to the hollow sleeve. In use, after the hollow sleeve is implanted into the soil, the probe is inserted into the soil from the top of the hollow sleeve to collect data. After the data collection is completed, the hollow sleeve is retained as a drainage channel, and the one-way valve prevents groundwater backflow.

[0014] The beneficial effects of the civil engineering foundation pit protection and support construction method provided by this invention are as follows: Compared with the prior art, the civil engineering foundation pit protection and support construction method of this invention first performs soil pretreatment. Drainage components integrated with probes are deployed around the foundation pit, allowing for real-time collection of soil data such as moisture content and cohesion without the need for separate survey points. Simultaneously, a vacuum preloading system is activated, dynamically adjusting the negative pressure value according to the moisture content, avoiding reinforcement imbalances caused by traditional empirical parameters. Furthermore, grouting pipes are interspersed between the drainage components, and grouting is performed in stages according to the soil reinforcement progress until monitoring data shows that the soil compression tends to stabilize. This avoids the lag problem of the survey-before-reinforcement process and effectively prevents initial deformation, insufficient reinforcement, or excessive waste of soft soil during the transition period. Subsequently, water-stopping construction is carried out. A rotary drilling rig is used to drill holes and install piles at the designed spacing. After the piles are cast, liquid grout is immediately injected into the gaps between the piles through pre-set pipes. During the grouting process, leakage is monitored in real time and the pressure is adjusted to quickly form a continuous water-stopping retaining wall. This approach eliminates the risk of leakage caused by intervals between processes. The dynamic pressure adjustment design adapts to differences in the gaps between piles, ensuring both water-stopping effect and preventing damage to the piles. Verification is not required after excavation, significantly reducing rework costs and project delays. Next, the coordinated installation of supports and monitoring allows for rapid installation of support steel sections via pre-set connectors after layered excavation of the foundation pit, eliminating time-consuming on-site welding and shortening the pit's exposure time. While using a jacking device for staged pressurization, stress sensors are deployed at connection nodes. Feedback data is used to instantly correct pressure values, preventing situations where support pressurization and monitoring are disconnected, leading to high stress loss rates. This ensures precise matching of support stiffness to soil load, reducing the risk of support deformation. Furthermore, displacement and crack monitoring devices are deployed at key parts of the retaining wall and around the foundation pit to capture data in real time. When monitored values ​​exceed preset thresholds, the system automatically instructs the jacking device to pressurize or depressurize, reducing abnormal response time from hours to minutes, eliminating the safety hazards of delayed manual response and potential loss of control due to wireless interruptions. Finally, the waste generated during construction is processed into recycled aggregate for backfilling, eliminating the need for off-site transportation and disposal. This completely solves the problems of environmental pollution and high transportation costs associated with traditional waste disposal, and achieves resource recycling.

[0015] In this way, multiple steps are coordinated and linked, integrating the traditionally fragmented processes into an organic whole, dynamically adapting to changes in soil and construction conditions. This not only improves the safety and stability of foundation pit support, but also shortens the construction cycle and reduces material consumption and environmental costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the construction method for the protection and support of civil engineering foundation pits provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0019] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0020] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] Please see Figure 1The present invention describes a construction method for the protection and support of a civil engineering foundation pit. The method includes: S1: Installing drainage components with probes around the foundation pit and collecting soil data; simultaneously starting a vacuum preloading system, adjusting the negative pressure value according to the soil data, and performing graded grouting reinforcement by inserting grouting pipes through the gaps in the drainage components until the monitored soil data stabilizes and preloading is stopped; S2: Drilling and planting piles at intervals using a rotary drilling rig, injecting grout into the gaps between the piles after the piles are cast, and monitoring the leakage between the piles in real time during the grouting process to adjust the grouting pressure and form a continuous stop. S3: Excavate the foundation pit in layers. After each layer is excavated, install supporting steel. Use a pressure jack to apply pressure to the supporting steel in stages. At the same time, deploy stress sensors to provide feedback data and correct the pressure value. S4: Install displacement monitoring devices and crack monitoring devices around the retaining wall and the foundation pit. When the data monitored by the displacement monitoring device and the crack monitoring device exceeds the threshold, start the pressure stabilizer to replenish or release pressure. S5: After the foundation pit construction is completed, use the waste generated in steps S1-S4 as recycled aggregate for backfilling.

[0023] The construction method for civil engineering foundation pit protection and support provided by this invention, compared with the prior art, firstly involves soil pretreatment. Drainage components integrated with probes are deployed around the foundation pit, allowing for real-time collection of soil data such as moisture content and cohesion without the need for separate survey points. Simultaneously, a vacuum preloading system is activated, dynamically adjusting the negative pressure value based on the moisture content, avoiding reinforcement imbalances caused by traditional empirical parameters. Furthermore, grouting pipes are interspersed between the drainage components, and grouting is performed in stages according to the soil reinforcement progress until monitoring data shows that the soil compression tends to stabilize. This avoids the lag problem of surveying before reinforcement and effectively prevents initial deformation, insufficient reinforcement, or excessive waste in soft soil during the transition period. Subsequently, water-stopping construction is carried out using a rotary drilling rig to drill holes and install piles at the designed spacing. After the piles are cast, liquid grout is immediately injected into the gaps between the piles through pre-set pipes. During the grouting process, leakage is monitored in real time and the pressure is adjusted to quickly form a continuous water-stopping retaining wall. This approach eliminates the risk of leakage caused by intervals between processes. The dynamic pressure adjustment design adapts to differences in the gaps between piles, ensuring both water-stopping effect and preventing damage to the piles. Verification is not required after excavation, significantly reducing rework costs and project delays. Next, the coordinated installation of supports and monitoring allows for rapid installation of support steel sections via pre-set connectors after layered excavation of the foundation pit, eliminating time-consuming on-site welding and shortening the pit's exposure time. While using a jacking device for staged pressurization, stress sensors are deployed at connection nodes. Feedback data is used to instantly correct pressure values, preventing situations where support pressurization and monitoring are disconnected, leading to high stress loss rates. This ensures precise matching of support stiffness to soil load, reducing the risk of support deformation. Furthermore, displacement and crack monitoring devices are deployed at key parts of the retaining wall and around the foundation pit to capture data in real time. When monitored values ​​exceed preset thresholds, the system automatically instructs the jacking device to pressurize or depressurize, reducing abnormal response time from hours to minutes, eliminating the safety hazards of delayed manual response and potential loss of control due to wireless interruptions. Finally, the waste generated during construction is processed into recycled aggregate for backfilling, eliminating the need for off-site transportation and disposal. This completely solves the problems of environmental pollution and high transportation costs associated with traditional waste disposal, and achieves resource recycling.

[0024] In this way, multiple steps are coordinated and linked, integrating the traditionally fragmented processes into an organic whole, dynamically adapting to changes in soil and construction conditions. This not only improves the safety and stability of foundation pit support, but also shortens the construction cycle and reduces material consumption and environmental costs.

[0025] Please see Figure 1As a specific implementation of the civil engineering foundation pit protection and support construction method provided by the present invention, in S1, the drainage component is connected to the vacuum preloading system and the grouting pipeline. The soil data collected by the probe generates real-time linkage commands for preloading and grouting. When the moisture content in the soil data is higher than the preset range, the negative pressure value of the vacuum preloading system is increased to accelerate drainage; when the cohesion in the soil data is lower than the threshold, the grouting pipeline is automatically triggered to perform grouting reinforcement, so as to realize adaptive reinforcement driven by dual parameters of moisture content and cohesion. In this way, a linkage mode integrating drainage, preloading, and grouting is constructed, in which the drainage component is the central carrier to realize real-time coordinated control of detection, drainage, pressurization, and grouting. By dynamically capturing the two parameters of moisture content and cohesion through the probe, the data is converted into precise linkage commands, forming a closed-loop control of data acquisition, intelligent decision-making, and equipment execution. Specifically, when the moisture content exceeds the preset range, the vacuum preloading negative pressure is automatically increased to accelerate drainage and quickly reduce the soil moisture content; when the cohesion is lower than the threshold, the grouting pipeline reinforcement is immediately triggered to directionally improve the soil strength, thereby achieving adaptive reinforcement driven by dual parameters.

[0026] This approach precisely adapts to dynamic soil changes, avoiding the blind reliance on experience-based parameter settings. Single-parameter control can easily lead to imbalances such as "over-drainage but insufficient strength" or "excessive grouting but excessive moisture content." This dual-parameter linkage simultaneously ensures both soil dry density and structural strength. Furthermore, the drainage components are directly connected to the dual systems, eliminating delays between equipment and allowing for faster control response. This solves the problem of process lag, preventing initial deformation of soft soil during the interval period; and by dynamically adapting to soil conditions, it eliminates the risk of later collapse due to insufficient reinforcement or material waste caused by excessive grouting.

[0027] Please see Figure 1As a specific embodiment of the construction method for the protection and support of civil engineering foundation pits provided by the present invention, in S1, drainage components are set up according to the division of foundation pit areas. The drainage components of each foundation pit area are connected to an independent vacuum preloading control valve. The probe collects data of each foundation pit area and transmits it to the vacuum preloading system. Based on the soil data, potential risk areas in the foundation pit are identified, and grout is injected into the potential risk areas first. After the grout solidifies to form a closed isolation shell, conventional grouting is carried out to implement graded grouting. After the preloading is completed, a trench is excavated outside the excavation edge of the foundation pit. The trenches are filled with graded sand and gravel to form stress relief trenches, forming a soil pretreatment system with precise zoning control, proactive risk prevention, and residual stress release. This system is based on the division of the foundation pit area, equipping each area's drainage components with independent vacuum preloading control valves. Combined with zoning data collection from probes, it achieves precise regional adaptation of preloading intensity. Simultaneously, potential risk areas are identified through soil data, employing a progressive reinforcement logic of pre-grouting to form a shell, followed by conventional graded grouting, supplemented by stress relief trenches after preloading, forming a comprehensive soil improvement solution. Independent zoning valves ensure that preloading is no longer affected by overall soil variations, allowing for precise pressure application to areas with different moisture contents and cohesion. The closed isolation shell formed by pre-grouting in risk areas prevents grout diffusion and loss during conventional grouting and pre-solidifies weak areas, avoiding risk transmission. The stress relief trenches provide a release channel for residual stress generated during preloading.

[0028] In this way, the uniformity of soil reinforcement in each area is improved by using zonal preloading, avoiding insufficient or excessive reinforcement in some areas; and the risk pretreatment reduces the risk of collapse during foundation pit excavation, which is especially suitable for hidden weak areas in soft soil foundations; at the same time, the stress relief trench effectively reduces the lateral deformation of the soil during the excavation stage, making the retaining wall more stable under subsequent stress.

[0029] Please see Figure 1 As a specific implementation of the civil engineering foundation pit protection and support construction method provided by this invention, the drainage component also includes a geological stratification correction module. When the probe identifies that the soil has entered different geological strata, the geological stratification correction module automatically adjusts the weighting coefficients of water content and cohesion. With the help of the geological stratification correction module, the drainage component has the ability to control geological adaptability, and achieves dynamic matching between the interpretation of probe data and geological conditions by integrating the geological stratification correction module. When the probe identifies that the soil has entered different strata such as sand layer and clay layer, the module automatically adjusts the weighting coefficients of water content and cohesion, instead of using the traditional fixed parameter evaluation standard, and no longer interpreting the soil data of the entire area with a single weight. Different geological strata have fundamentally different dominant influencing factors on support safety. For example, excessive water content in sand layer is prone to quicksand, so the weight should focus on water content; insufficient cohesion in clay layer is prone to plastic deformation, so the weight should be tilted towards cohesion. The automatic correction of the module makes the data-driven approach more in line with the actual geological characteristics.

[0030] This structure improves the accuracy of soil reinforcement commands, avoiding control deviations caused by misjudgment of layer characteristics, such as more efficient drainage of sand layers and more targeted grouting of clay layers; it also reduces local reinforcement defects caused by insufficient geological compatibility and lowers the risk of soil collapse during foundation pit excavation.

[0031] Please see Figure 1 As a specific embodiment of the construction method for civil engineering foundation pit protection and support provided by the present invention, in step S2, a leakage monitoring device is arranged to monitor leakage parameters between piles. A guide pipe is connected between the leakage monitoring device and the grouting pipeline, and an automatic control valve is installed on the guide pipe. When the leakage monitoring device detects a leakage signal, the automatic control valve opens, guiding the grout in the grouting pipeline to flow to the leakage point through the guide pipe. Through the organic linkage of the leakage monitoring device, the guide pipe, and the automatic control valve, the traditional large-area blind grouting water-stopping mode is upgraded to a targeted and precise leakage repair dynamic response mode. Specifically, the leakage monitoring device deployed between piles captures parameters such as leakage location and speed in real time. One end of the guide pipe is connected to the leakage monitoring point, and the other end is connected to the grouting pipeline, and the automatic control valve on the pipeline is linked to the signal of the monitoring device. When a leakage signal is detected, the control valve opens immediately, guiding the grout along the guide pipe directly to the leakage point, realizing the synchronous response of leakage triggering and grout repair. This method, through directional flow guidance and automatic control, allows the grout to be precisely focused on the leakage point, avoiding grout waste and eliminating the contradiction of unsealed leaks and pile damage due to pressure overload. It is suitable for actual working conditions with varying gap sizes between piles. Using this method, the response time for leakage treatment is reduced from the traditional 2-4 hours to minutes, allowing for sealing in the early stages of leakage. This also improves the success rate of water stopping, eliminating the need for rework after excavation and increasing grout utilization. Furthermore, directional grouting avoids additional pressure on the pile body, ensuring the structural integrity of the retaining wall and providing a solid guarantee for the stability of subsequent foundation pit excavation.

[0032] Please see Figure 1As a specific implementation of the construction method for the protection and support of civil engineering foundation pits provided by the present invention, in S2, annular grouting channels are set at preset intervals along the depth direction of the retaining wall, and the grouting channels are connected to the grouting pipes of each pile. When monitoring detects local water-stopping failure, repair grout is injected into the corresponding grouting channel through the ground interface to carry out deep water-stopping repair without excavation. During the construction stage of the retaining wall, a deep water-stopping repair system with vertical layers and circumferential connections is preset. Annular grouting channels are laid out at preset intervals along the depth direction of the retaining wall, and each channel is connected to the grouting pipes of all piles to form a network repair path covering the entire depth of the retaining wall. When monitoring detects deep or local water-stopping failure, there is no need to excavate and break the constructed structure. Repair grout is injected into the annular grouting channel of the corresponding depth through the ground reserved interface to achieve precise repair. By using a pre-set annular channel to extend the repair interface to the ground, grouting can be precisely selected according to the monitored and located failure depth. The grout quickly diffuses into the failure area between piles through the annular channel, avoiding blind construction and structural damage, and adapting to the repair needs of water-stopping defects at different depths. This implementation method shortens the repair time for deep water-stopping and avoids the weakening of the retaining wall caused by excavation and wall breaking, greatly improving the integrity of the repaired wall and the recovery rate of water-stopping performance.

[0033] Please see Figure 1 As a specific embodiment of the construction method for civil engineering foundation pit protection and support provided by the present invention, stress-compensating joints are installed in the foundation pit to install supporting steel. The stress-compensating joints are used to release elastic potential energy to compensate for displacement when the supporting steel is deformed under stress. The exposure time of the foundation pit excavation surface is monitored in real time. If the exposure time exceeds the preset time, the interval of staged pressurization is shortened to reduce soil stress loss. In this method, stress-compensating joints are used to connect the supporting steel in the foundation pit. The joints have built-in elastic energy storage components, which can compensate for displacement by releasing elastic potential energy when the supporting steel is deformed under stress due to soil load. At the same time, the staged pressurization operation is linked to the exposure time of the foundation pit excavation surface in real time. The exposure time is tracked by monitoring equipment. Once the preset threshold is exceeded, the pressurization interval is immediately shortened to enhance the stress compensation effect. Thus, a support system installation guarantee mechanism with adaptive support deformation and dynamic optimization of pressurization sequence is formed.

[0034] Compared to traditional support joints, which are prone to stress concentration and cracking under stress and deformation, and suffer from soil creep due to prolonged exposure of the excavation face caused by fixed pressurization intervals, the flexible design of stress-compensating joints can buffer load impacts and prevent support damage due to deformation. The linked pressurization during exposure can actively cope with the effects of soil creep, ensuring that the support stress always meets the design requirements. The two form a dual protection of deformation buffering and stress energy compensation. This reduces the risk of cracking of the support steel due to deformation, and the elastic compensation function of the joint effectively extends the service life of the support. In addition, the support stress loss rate is also significantly reduced, and the horizontal displacement control accuracy of the foundation pit retaining wall is improved.

[0035] Please see Figure 1 As a specific implementation of the civil engineering foundation pit protection and support construction method provided by this invention, a control terminal is also provided in S4. The control terminal includes a multi-source data verification module. The multi-source data verification module receives readings from displacement monitoring devices and crack monitoring devices, surface image recognition results taken by UAVs, and monitoring data from nearby monitoring points. After performing consistency comparison, it determines whether the monitoring data is valid. This implementation forms a multi-dimensional data cross-verification monitoring quality control system. With the multi-source data verification module of the control terminal as the core, it integrates the direct readings of displacement monitoring devices and crack monitoring devices, superimposes the visualization results of UAV surface image recognition, and the associated data of nearby monitoring points. The validity of single-source data is determined through a logical consistency comparison algorithm. Multi-source verification, through direct monitoring, image corroboration, and surrounding reference triple verification, can quickly identify abnormal data (such as a sudden change in a sensor reading but no cracks in the image or no change in nearby points), avoids the one-sidedness of single data, improves the efficiency of monitoring data, and eliminates operational risks such as false data causing false pressure replenishment or false pressure release.

[0036] Please see Figure 1 As a specific embodiment of the construction method for civil engineering foundation pit protection and support provided by the present invention, in S5, the preparation of recycled aggregate includes mixing demolition waste with waste industrial solid waste, spraying an active activator into the mixture, and enhancing the activity of the aggregate through the chemical reaction between the active activator and the solid waste; the backfilling of recycled aggregate is carried out in conjunction with the construction of the waterproof layer. When backfilling reaches the preset position at the bottom of the waterproof layer, the aggregate is manually spread, and modified asphalt emulsion is injected into the aggregate. After the emulsion penetrates the gaps in the aggregate to form a sealing layer, subsequent backfilling is carried out. During the preparation of recycled aggregate, the demolition waste is mixed with waste industrial solid waste, and an active activator is sprayed to activate the potential activity of the solid waste through a chemical reaction; the backfilling stage is coordinated with the construction depth of the waterproof layer. When backfilling reaches the preset position at the bottom of the waterproof layer, the aggregate is manually spread and modified asphalt emulsion is injected. After the emulsion penetrates the gaps to form a sealing layer, backfilling continues, realizing the integration of backfilling and waterproofing; the active activator enhances the strength and durability of the aggregate through chemical action, and the modified asphalt emulsion sealing layer eliminates the interface gap between the backfill and the waterproof layer. This approach enhances the activity of recycled aggregates and the compaction of backfill, reducing settlement. The sealing layer also improves the waterproofing pass rate, preventing future leakage repairs. The coordinated backfilling and waterproofing operations shorten the construction period and eliminate the need for traditional joint treatment procedures between the waterproofing layer and the backfill layer.

[0037] Please see Figure 1As a specific embodiment of the construction method for civil engineering foundation pit protection and support provided by the present invention, in S1, the drainage component includes a hollow sleeve and a one-way valve installed on the hollow sleeve, and a probe is detachably connected to the hollow sleeve. In use, after the hollow sleeve is implanted into the soil, the probe is inserted into the soil from the top of the hollow sleeve to collect data. After data collection, the hollow sleeve is retained as a drainage channel, and the one-way valve prevents groundwater backflow. The drainage component uses the hollow sleeve as its core carrier, integrating a detachable probe and a one-way valve, achieving a design that allows for one-time implantation into the soil and step-by-step functionalization. After the hollow sleeve is implanted, the detachable probe is inserted from the top to complete soil data collection. After collection, only the probe is removed, leaving the sleeve as a drainage channel, while the one-way valve blocks groundwater backflow, breaking the traditional model where detection and drainage require separate equipment deployment. By sharing the hollow sleeve, a dual-purpose effect is achieved, reducing the number of soil disturbances; the detachable probe can be reused at multiple points, reducing equipment consumption; and the one-way valve ensures unobstructed drainage in one direction, preventing secondary water accumulation.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for protection and support of civil engineering foundation pits, characterized in that, include: S1: Deploy drainage components with probes around the foundation pit and collect soil data; The vacuum preloading system is started simultaneously, the negative pressure value is adjusted according to the soil data, and the grouting pipeline is inserted into the gap of the drainage components to carry out graded grouting reinforcement until the soil data is monitored to stabilize and then the preloading is stopped. S2: Rotary drilling rigs are used to drill holes and install piles at intervals. After the piles are cast and formed, liquid grout is injected into the gaps between the piles. During the grouting process, the leakage between the piles is monitored in real time to adjust the grouting pressure and form a continuous water-stopping retaining wall. S3: Excavate the foundation pit in layers. After each layer is excavated, install supporting steel. Use a top pressure device to apply pressure to the supporting steel in stages. At the same time, install stress sensors to provide feedback data and correct the pressure value. S4: Displacement monitoring devices and crack monitoring devices are installed around the retaining wall and the foundation pit. When the monitoring data of the displacement monitoring device and the crack monitoring device exceeds the threshold, the pressure regulator is activated to replenish or release pressure. S5: After the foundation pit construction is completed, the waste generated in steps S1-S4 is used as recycled aggregate for backfilling.

2. The construction method for protection and support of civil engineering foundation pits as described in claim 1, characterized in that, In S1, the drainage component is connected to the vacuum preloading system and the grouting pipeline. The soil data collected by the probe generates a real-time preloading and grouting linkage command. When the moisture content in the soil data is higher than a preset range, the negative pressure value of the vacuum preloading system is increased to accelerate drainage. When the cohesion in the soil data is lower than a threshold, the grouting pipeline is automatically triggered to perform grouting reinforcement, so as to realize adaptive reinforcement driven by dual parameters of moisture content and cohesion.

3. The construction method for protection and support of civil engineering foundation pits as described in claim 2, characterized in that, In S1, the drainage components are set up according to the division of the foundation pit area. The drainage components of each foundation pit area are connected to an independent vacuum preloading control valve. The probe collects the data of each foundation pit area and transmits it to the vacuum preloading system. Based on the soil data, potential risk areas in the foundation pit are identified, and grout is injected into the potential risk areas first. After the grout solidifies to form a closed isolation shell, conventional grouting is carried out to implement graded grouting. After the preloading is completed, a trench is excavated outside the excavation edge of the foundation pit, and the trench is filled with graded sand and gravel to form a stress relief trench.

4. The construction method for protection and support of civil engineering foundation pits as described in claim 2, characterized in that, The drainage component also includes a geological stratification correction module. When the probe detects that the soil has entered different geological strata, the geological stratification correction module automatically adjusts the weighting coefficients of moisture content and cohesion.

5. The construction method for protection and support of civil engineering foundation pits as described in claim 1, characterized in that, In S2, a leakage monitoring device is installed to monitor leakage parameters between piles. A guide pipe is connected between the leakage monitoring device and the grouting pipeline. An automatic control valve is installed on the guide pipe. When the leakage monitoring device detects a leakage signal, the automatic control valve opens and guides the grout in the grouting pipeline to flow to the leakage point through the guide pipe.

6. The construction method for protection and support of civil engineering foundation pits as described in claim 5, characterized in that, In S2, annular grouting channels are set at preset intervals along the depth direction of the retaining wall, and the grouting channels are connected to the grouting pipes of each pile. When monitoring detects local water-stopping failure, repair grout is injected into the corresponding grouting channel through the ground interface, achieving deep water-stopping repair without excavation.

7. The construction method for protection and support of civil engineering foundation pits as described in claim 1, characterized in that, Stress-compensating joints are installed in the foundation pit to install supporting steel. The stress-compensating joints are used to release elastic potential energy to compensate for displacement when the supporting steel is deformed under stress. The exposure time of the foundation pit excavation surface is monitored in real time. If the exposure time exceeds the preset time, the interval of staged pressurization is shortened to reduce soil stress loss.

8. The construction method for protection and support of civil engineering foundation pits as described in claim 1, characterized in that, S4 also includes a control terminal, which includes a multi-source data verification module. The multi-source data verification module receives the readings of the displacement monitoring device and the crack monitoring device, the recognition results of the surface image taken by the UAV, and the monitoring data of the adjacent monitoring points, and determines whether the monitoring data is valid after performing a consistency comparison.

9. The construction method for protection and support of civil engineering foundation pits as described in claim 1, characterized in that, In S5, the recycled aggregate includes mixing demolition waste and waste industrial solid waste, spraying an active activator into the mixture, and enhancing the activity of the aggregate through the chemical reaction between the active activator and the solid waste. The backfilling of the recycled aggregate is carried out in conjunction with the construction of the waterproof layer. When backfilling to the preset position at the bottom of the waterproof layer, the aggregate is spread manually, and modified asphalt emulsion is injected into the aggregate. After the emulsion penetrates the gaps between the aggregate to form a sealing layer, subsequent backfilling is carried out.

10. The construction method for protection and support of civil engineering foundation pits as described in claim 1, characterized in that, In S1, the drainage assembly includes a hollow sleeve and a one-way valve installed on the hollow sleeve. The probe is detachably connected to the hollow sleeve. In use, after the hollow sleeve is implanted into the soil, the probe is inserted into the soil from the top of the hollow sleeve to collect data. After the data collection is completed, the hollow sleeve is retained as a drainage channel, and the one-way valve prevents groundwater backflow.

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