Smart dewatering and water stopping method for foundation pit

Abstract

A smart dewatering and water stopping method for a foundation pit, the method comprising the following steps: step S1, dewatering: arranging a plurality of dewatering wells, arranging dewatering water pumps, and lowering a water level in each dewatering well to a preset position by means of each dewatering water pump; step S2, drainage: arranging water collection systems, and draining water from inside a foundation pit by means of the water collection systems; step 3, water blocking: arranging an underground water blocking barrier to prevent underground water outside the foundation pit from flowing into the foundation pit; step S4, water cut-off: arranging a water blocking wall to block water-layer interflow between the interior of the foundation pit and the exterior of the foundation pit; and step S5, performing well water level monitoring, and starting an emergency measure: when a water level exceeds a preset safety range or a stability index of the foundation pit is reduced, starting an automatic emergency measure system. In the present application, for underground water control, the automatic emergency measure system is used to achieve the aims of smart dewatering and water stopping of the foundation pit.

Description

Intelligent dewatering and water stopping method for foundation pit TECHNICAL FIELD

[0001] The application belongs to the technical field of foundation pit dewatering, and particularly relates to an intelligent dewatering and water stopping method for foundation pit. BACKGROUND

[0002] Foundation pit dewatering refers to dewatering work for ensuring that a foundation pit can be constructed under dry conditions to prevent side slope instability, foundation quicksand, pit bottom heave, pit bottom piping and foundation bearing capacity reduction when the underground water level is higher than the excavation bottom surface during excavation of the foundation pit.

[0003] Underground water is one of the common problems in foundation pit engineering and has an important influence on safe construction and engineering quality of the foundation pit engineering. Therefore, appropriate underground water control technology is an important link in the foundation pit engineering. Since the water level drawdown curve around the foundation pit is quite different due to different dewatering requirements, dewatering methods and specific schemes, different dewatering methods need to be analyzed and compared under the premise of meeting the basic dewatering requirements to screen the best dewatering scheme.

[0004] Therefore, it is necessary to provide an improved technical scheme for the above-mentioned deficiencies of the prior art. SUMMARY

[0005] The purpose of the application is to provide an intelligent dewatering and water stopping method for foundation pit to solve or alleviate the problems existing in the prior art and provide a new solution for deep foundation pit excavation in a lake area.

[0006] In order to achieve the above-mentioned purpose, the application provides the following technical scheme:

[0007] An intelligent dewatering and water stopping method for foundation pit, which is improved in that the method comprises the following steps:

[0008] Step S1, dewatering: a plurality of dewatering wells are arranged on the periphery of the foundation pit; a dewatering pump is arranged in the dewatering well; and the water level in the dewatering well is lowered to a preset position by the dewatering pump;

[0009] Step S2, drainage: a water collecting system is arranged at the bottom and side wall of the foundation pit; the water collecting system comprises a water collecting well and a water collecting pipe; and the water in the foundation pit is drained out through the water collecting system;

[0010] Step S3, water plugging: an underground water blocking barrier is arranged around the foundation pit to block the underground water outside the foundation pit from flowing into the inside of the foundation pit;

[0011] Step S4, water interception: a water stopping curtain is arranged on the periphery of the foundation pit to block the water layer exchange between the inside of the foundation pit and the outside of the foundation pit;

[0012] Step S5, well water level monitoring, starting emergency measures: when its water level exceeds the preset safety range or the stability index of the foundation pit decreases, the automatic emergency measures system is started; starting the automatic emergency measures system includes starting the dewatering pump to dewater until the design water level is reached;

[0013] Step S1, the setting depth, setting position and setting interval of the dewatering well are determined according to the groundwater flow model and the lake water level dynamic change model:

[0014] Step S1-1, determining the setting depth of the dewatering well according to the groundwater flow model includes: according to the groundwater flow model, the depth of the dewatering well needs to reach the aquifer so as to control the groundwater level in the foundation pit area; the setting depth of the dewatering well is determined according to the annual average water level of the groundwater level, seasonal fluctuation, and groundwater flow direction and flow rate;

[0015] Step S1-2, determining the setting position of the dewatering well according to the groundwater flow model includes: the setting position of the dewatering well is based on the groundwater flow direction and flow rate, and the dewatering well is arranged on the main groundwater flow path to enhance the dewatering efficiency;

[0016] Step S1-3, determining the setting interval of the dewatering well according to the groundwater flow model includes: the interval of the multiple dewatering wells is determined according to the groundwater flow model, the multiple dewatering wells cover the entire foundation pit area, the multiple dewatering wells are independent of each other, and the groundwater level of the entire foundation pit area can be uniformly lowered;

[0017] Step S1-4, determining the setting depth of the dewatering well according to the lake water level dynamic change model includes: according to the seasonal and interannual changes of the lake water level, the depth of the dewatering well needs to adapt to the groundwater pressure during the highest period of the lake water level, and can control the water level inside the foundation pit during the highest period of the lake water level;

[0018] Step S1-5, determining the setting position of the dewatering well according to the lake water level dynamic change model includes: according to the lake water level dynamic change model, the dewatering well is arranged on the side close to the lake or water body so as to control the situation that the groundwater level rises due to the rise of the lake water level;

[0019] Step S1-6, determining the setting interval of the dewatering well according to the lake water level dynamic change model includes: based on the dynamic change of the lake water level, the interval of the multiple dewatering wells is set according to the lake water level change and the groundwater flow direction, which can control the groundwater level in the foundation pit area during the peak period of the lake water level;

[0020] The emergency measures in step S5 include:

[0021] Step S5-1, water level sensors are arranged inside and outside the foundation pit, and the water level sensors are connected with the automatic monitoring system; the water level sensors and the automatic monitoring system are used to collect water level data and stability indexes inside and outside the foundation pit in real time, so as to evaluate the dewatering effect and the water level stability of the foundation pit;

[0022] Step S5-2, inclinometers and stress sensors are arranged in the soil around the foundation pit; the inclinometers and the stress sensors are used to monitor the displacement and stress change of the soil around the foundation pit and the supporting structure, and the soil mechanical property data, such as the density, the void ratio, the internal friction angle and the cohesion of the soil, are obtained through field tests and laboratory tests; the total station, the global navigation satellite system and the laser scanning measurement technology are used to obtain the deformation data, so as to monitor the settlement and horizontal displacement of the foundation pit and the ground around the foundation pit;

[0023] Step S5-3, the relevant data in step S5-1 and step S5-2 are collected, and the relevant data include the water level data, the stability indexes, the soil mechanical property data and the deformation data;

[0024] Step S5-4, the relevant data are analyzed; if the relevant data are within the preset range, steps S5-1 to S5-3 are repeatedly executed; if the relevant data are out of the preset range, step S5-5 is entered;

[0025] Step S5-5, when the water level rises or the stability of the foundation pit decreases, the dewatering well is started and the injection amount of the chemical water stop agent is increased;

[0026] Step S5-6, steps S5-1 to S5-5 are repeatedly executed until all the relevant data are within the preset range. Advantageous effects:

[0027] (1) The application proposes to arrange dewatering wells at appropriate positions in the surrounding area of the foundation pit according to the geological structure and the hydrogeological conditions, and each dewatering well is equipped with a high-efficiency dewatering pump, and the design purpose is to effectively reduce the underground water level through continuous dewatering activities.

[0028] (2) The application arranges a water collecting system at the bottom and the sidewall of the foundation pit, and the system includes a water collecting pipe and a water collecting well, and the main function of the system is to quickly discharge the surface water and the underground water accumulated in the foundation pit.

[0029] (3) The application constructs an underground water blocking barrier around the foundation pit, and the function of the barrier is to guide the underground water to a controllable area, so as to effectively control the underground water level.

[0030] (4) The application sets up a water stop curtain outside the foundation pit, and the curtain effectively separates the underground water inside and outside the foundation pit by using physical isolation means, and then the underground water outside the foundation pit is pumped out.

[0031] (5)The application also includes a set of emergency measures, when the water level or stability index is abnormal, automatically start additional precipitation measures and increase the amount of water stop injection, to ensure the absolute safety of the foundation pit. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is the flow chart of the foundation pit intelligent dewatering and water stopping steps involved in the application;

[0033] Figure 2 is a schematic diagram of the dewatering well structure used in the application;

[0034] Figure 3 is a schematic diagram of the distribution of dewatering wells, drainage wells and observation wells involved in one embodiment of the application;

[0035] Figure 4 is a flow chart of the construction steps of the dewatering well involved in the application;

[0036] Wherein: 1, skeleton reinforcement; 2, reinforcing hoop; 3, filter layer; 4, nylon net; 5, pump pipe. DETAILED DESCRIPTION

[0037] Foundation pit dewatering refers to the work of dewatering done to ensure that the foundation pit can be constructed under dry conditions when the underground water level is higher than the excavation bottom surface during excavation of the foundation pit, to prevent slope instability, foundation quicksand, pit bottom heaving, pit bottom piping and reduction of foundation bearing capacity.

[0038] Underground water is one of the common problems in foundation pit engineering, which has important influence on the safe construction and engineering quality of foundation pit engineering. Therefore, taking appropriate underground water control technology is an important part of foundation pit engineering. Because the water level drawdown curve around the foundation pit varies greatly with different dewatering requirements, dewatering methods and specific schemes, under the premise of meeting the basic dewatering requirements, different dewatering methods need to be analyzed and compared to select the best dewatering scheme.

[0039] The foundation pit intelligent dewatering and water stopping method involved in the application can be summarized as four methods of "dewatering, drainage, plugging and interception". "Dewatering" means pumping water with various measures to achieve the goal of lowering the underground water level; "drainage" means collecting and draining water, which can be used for surface water and underground water; "plugging" means blocking and intercepting measures to control the area of underground water, so as to control the underground water level; "interception" means stopping the curtain to separate the underground water inside and outside the foundation pit by physical methods, and then pumping the underground water outside the foundation pit to achieve the purpose of underground water control. Deep foundation pit engineering, mine engineering, bridge and tunnel engineering, slope engineering, road engineering and dam engineering all involve the problem of underground water control.

[0040] As shown in Figure 1, the application relates to a foundation pit intelligent dewatering and water stopping method, which is improved in that the method comprises the following steps:

[0041] Step S1, precipitation: multiple precipitation wells are set in the peripheral zone of the foundation pit; a precipitation pump is set in the precipitation well; the water level in the precipitation well is lowered to a preset position by the precipitation pump. It includes: in the peripheral zone of the foundation pit, the setting position of the precipitation well is determined according to the geological structure and hydrogeological conditions, and the precipitation well is arranged at a suitable position; a precipitation pump is arranged in the precipitation well to ensure that each precipitation well is equipped with a high-efficiency precipitation pump; the water level in the precipitation well is lowered to a preset position by the precipitation pump. The purpose is to achieve effective reduction of underground water level through continuous precipitation activities, and to create a stable working environment for foundation pit excavation.

[0042] Step S2, drainage: a water collection system is set at the bottom and side wall of the foundation pit; the water collection system includes a water collection well and a water collection pipe; the water inside the foundation pit is drained through the water collection system to quickly discharge the accumulated surface water and underground water in the foundation pit and ensure that the inside of the foundation pit is in a dry state.

[0043] The water collection well adopts a specially treated reinforced concrete structure, such as adding waterproof agent and fiber reinforced concrete, to improve its stability and durability. The water collection pipe is arranged at the center of the water collection well and below the foundation pit bottom plate, and guides the water flow to the water collection well through a slope; the water collection well should be arranged at the low point of the foundation pit to utilize gravity drainage.

[0044] Step S3, water blocking: a groundwater blocking barrier is set around the foundation pit to block the inflow of groundwater outside the foundation pit into the inside of the foundation pit. It includes: around the foundation pit, a groundwater blocking barrier is constructed using specific materials or technical means to block the inflow of groundwater outside the foundation pit into the inside of the foundation pit, so as to guide the groundwater to a controllable area, thereby effectively controlling the groundwater level and minimizing the adverse effects of groundwater on the foundation pit.

[0045] Step S4, water interception: a water stop curtain is set around the foundation pit to block the exchange of water layers between the inside and outside of the foundation pit; it includes: a water stop curtain is set around the foundation pit, which effectively separates the groundwater inside and outside the foundation pit by physical isolation means; then the groundwater outside the foundation pit is pumped out to ensure that the water level inside the foundation pit is stable and achieves the expected control effect.

[0046] Step S5, well water level monitoring and emergency measures: when the water level exceeds the preset safety range or the stability index of the foundation pit decreases, the automatic emergency measures system is started; starting the automatic emergency measures system includes starting the precipitation pump to precipitate until the design water level.

[0047] The setting depth, setting position and setting interval of the precipitation well are determined according to the groundwater flow model and the lake water level dynamic change model:

[0048] Step S1-1, determining the setting depth of the dewatering well according to the groundwater flow model includes: according to the groundwater flow model, the depth of the dewatering well needs to reach the aquifer in order to control the groundwater level in the foundation pit area; the setting depth of the dewatering well is determined according to the annual average water level, seasonal fluctuations, and the direction and speed of groundwater flow.

[0049] Step S1-2, determining the setting position of the dewatering well according to the groundwater flow model includes: the setting position of the dewatering well is based on the direction and speed of groundwater flow, and the dewatering well is arranged on the main flow path of groundwater to enhance the dewatering efficiency. At the same time, considering the geological structure, it is avoided to be set on the geological fault or weak zone.

[0050] Step S1-3, determining the setting interval of the dewatering well according to the groundwater flow model includes: the interval of multiple dewatering wells is determined according to the groundwater flow model, the parts of multiple dewatering wells cover the entire foundation pit area, multiple dewatering wells are independent of each other, and the groundwater level of the entire foundation pit area can be uniformly lowered. At the same time, mutual interference is avoided.

[0051] Step S1-4, determining the setting depth of the dewatering well according to the lake water level dynamic change model includes: according to the seasonal and interannual changes of the lake water level, the depth of the dewatering well needs to adapt to the groundwater pressure during the highest period of the lake water level, and can control the water level inside the foundation pit during the highest period of the lake water level.

[0052] Step S1-5, determining the setting position of the dewatering well according to the lake water level dynamic change model includes: according to the lake water level dynamic change model, the dewatering well is arranged on the side close to the lake or water body in order to control the situation that the groundwater level rises due to the rise of the lake water level. Specifically, according to the lake water level dynamic change model, the dewatering well should be arranged in the area most affected by the change of the lake water level, especially on the side close to the lake or water body, in order to more effectively control the rise of the groundwater level due to the rise of the lake water level.

[0053] Step S1-6, determining the setting interval of the dewatering well according to the lake water level dynamic change model includes: based on the dynamic change of the lake water level, the interval of multiple dewatering wells is set according to the change of the lake water level and the direction of groundwater flow, which can control the groundwater level in the foundation pit area during the peak period of the lake water level. Specifically, based on the dynamic change of the lake water level, the interval of the dewatering well should be adjusted according to the sensitivity of the lake water level change and the direction of groundwater flow, to ensure that the groundwater level in the entire foundation pit area can be effectively controlled during the peak period of the lake water level, avoiding the phenomenon of lake water backflow.

[0054] Step S2, setting a water collecting system includes:

[0055] Step S2-1, determining the setting position of the water collecting well; the setting position of the water collecting well is determined according to the water flow direction and the concentration area inside the foundation pit; the water collecting well is arranged at the low point or the water flow concentration area at the bottom of the foundation pit so as to collect the accumulated water in the foundation pit.

[0056] Step S2-2, designing the structure of the water collecting well; the structure of the water collecting well is designed according to the depth of the foundation pit, the geological condition and the expected water amount; the capacity and the structural strength of the water collecting well meet the situation of collapse or blockage during the precipitation process.

[0057] Step S2-3, setting the water collecting pipe, including the layout design of the water collecting pipe; the water collecting pipe is arranged along the bottom and the sidewall of the foundation pit to form a water flow guiding and collecting network; the layout design of the water collecting pipe is designed according to the specific shape, size and water flow concentration characteristics of the foundation pit. Specifically, the material and specification selection of the water collecting pipe: according to the water amount and the geological condition in the foundation pit, the appropriate material (such as PVC, HDPE, etc.) and specification of the water collecting pipe are selected to ensure the durability of the pipe material and the sufficient flow passage; the installation and maintenance of the water collecting pipe: when the water collecting pipe is installed, it is necessary to ensure that there is sufficient slope to promote water flow and avoid dead angles or water accumulation. At the same time, the design should be convenient for later inspection and maintenance to ensure the long-term effective operation of the water collecting system.

[0058] Step S2-4, connecting the water collecting well; the water collecting pipe is connected with the water collecting well to ensure that the water collected in the water collecting well can be transported to the designated discharge position or treatment facility.

[0059] Step S3 setting the underground water blocking barrier includes:

[0060] Step S3-1, selecting the grouting material for forming the underground water blocking barrier, including: high molecular material or chemical water stopping agent, such as polyvinyl alcohol (PVA), polyacrylamide (PAM) or specific chemical water stopping agent such as acrylic resin grouting material;

[0061] Step S3-2, setting the grouting hole; the cement water glass double liquid slurry is injected into the surrounding of the foundation pit through the grouting hole. Specifically, the grouting hole is arranged on the inner side of the foundation pit to reinforce and stop water grouting for the soil outside the retaining pile. The grouting hole has a depth of 2.4m to 9.1m, the grouting range is from the outside of the initial retaining pile to the bottom of the grouting hole, and the grouting adopts the cement water glass double liquid slurry.

[0062] Step S3-3, the high molecular material or the chemical water stopping agent can combine with the water molecules in the soil to form a continuous and stable waterproof barrier around the foundation pit so as to isolate the underground water from entering the foundation pit.

[0063] Step S4 setting the water stopping curtain on the periphery of the foundation pit, and the specific scheme is: Step S4-1, selecting the material of the water stopping curtain, including polyethylene, polypropylene and polyvinyl chloride.

[0064] Step S4-2, setting the waterproof curtain: according to the geological conditions, hydrological conditions and construction environment around the foundation pit, the depth, thickness and arrangement of the waterproof curtain are designed; the waterproof curtain extends from the bottom of the foundation pit to the stratum at a predetermined depth, forming a water-blocking layer.

[0065] Specifically, step S4-1, selecting the material of the waterproof curtain: the selection of the material of the waterproof curtain needs to consider its waterproof effect, durability, adaptability to the environment and cost-effectiveness; high molecular materials such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and ethylene-vinyl acetate copolymer (EVA) are widely used as waterproof curtain materials due to their excellent waterproof performance, anti-aging ability and environmental adaptability; at the same time, considering sustainability and environmental protection, environmentally friendly waterproof materials can be used; the selected material should have good physical and chemical stability, be able to resist corrosion by chemical substances that may exist in groundwater; and should have sufficient mechanical strength and flexibility to adapt to geological changes or changes in ground load.

[0066] Step S4-2, setting the waterproof curtain: according to the geological conditions, hydrological conditions and construction environment around the foundation pit, the depth, thickness and arrangement of the waterproof curtain are designed; the waterproof curtain should extend from the bottom of the foundation pit to a certain depth of the stratum, forming an effective water-blocking layer, to effectively isolate the groundwater inside and outside the foundation pit, ensure that the waterproof curtain is connected with the groundwater barrier, form a continuous waterproof system, and maintain the water level stability in the foundation pit; appropriate construction techniques are used to set the waterproof curtain, common methods include underground continuous wall, steel sheet pile, chemical grouting, etc.; the selected method should ensure that the curtain can be continuous and seamless, effectively blocking the water flow; the joints of the waterproof curtain are the key part of the waterproof effect, which needs to be treated with special sealing materials and techniques to ensure the continuity and sealing of the whole curtain; after setting the waterproof curtain, a monitoring mechanism should be established to regularly check the integrity and waterproof effect of the curtain. If damage or leakage is found, it should be repaired or reinforced in time.

[0067] Step S5, well water level monitoring also includes: setting an observation well; the observation well structure is the same as the dewatering well, and is set outside the foundation pit; a liquid level meter is set in the observation well for automatic monitoring of the water level, and when the water level reaches ±5cm of the designed water level, the dewatering pump is automatically started to realize automatic dewatering of the foundation pit, ensuring the stability of the foundation pit.

[0068] The structure of the precipitation well and the observation well used in the present application is the same, as shown in FIG. 2, specifically: the type of the precipitation well is well pipe type, the precipitation well uses two-stage steel with a diameter of 10 mm and a spacing of 12 mm arranged uniformly along the circumference as the skeleton reinforcement 1, and at the same time uses reinforcing hoop reinforcement 2 with a diameter of 12 mm and a spacing of 250 mm to fix the skeleton reinforcement 1. The well head diameter of the precipitation well is 400 mm, a filter layer 3 with the same axis as the well and a thickness of 100 mm is arranged outside the well head, and the final well diameter is 600 mm. A 60-mesh nylon net 4 is also needed to be arranged between the well head and the filter layer 3 to wrap the precipitation well to filter sand and stone. A pump pipe 5 is arranged at the center position of the precipitation well.

[0069] The emergency measures in step S5 include:

[0070] Step S5-1, water level sensors are arranged inside the foundation pit and outside the foundation pit, and the water level sensors are connected with the automatic monitoring system; the water level sensors and the automatic monitoring system are used to collect water level data and stability indexes inside the foundation pit and outside the foundation pit in real time, so as to evaluate the precipitation effect and the water level stability of the foundation pit.

[0071] Step S5-2, inclinometers and stress sensors are arranged in the soil body around the foundation pit; the inclinometers and the stress sensors are used to monitor the displacement and stress change of the soil body around the foundation pit and the supporting structure; soil mechanical property data, such as the density, the void ratio, the internal friction angle and the cohesion parameters of the soil, are obtained through field tests and indoor tests; deformation data are obtained by using total station, global navigation satellite system and laser scanning measurement technology, so as to monitor the settlement and horizontal displacement of the foundation pit and the ground around it.

[0072] Step S5-3, the relevant data in step S5-1 and step S5-2 are collected, and the relevant data include water level data, stability indexes, soil mechanical property data and deformation data.

[0073] Step S5-4, the relevant data are analyzed; if the relevant data are within the preset range, steps S5-1 to S5-3 are repeatedly executed, and if the relevant data exceed the preset range, step S5-5 is entered. Specifically, the controller judges whether the emergency measures need to be started through the above data, and the controller can adopt an embedded system, a programmable logic controller or other control equipment.

[0074] Step S5-5, when the water level rises or the stability of the foundation pit decreases, the precipitation well is started and the injection amount of the chemical water stop agent is increased to quickly respond to the situation of the rising water level or the decreasing stability of the foundation pit. Specifically, the execution device is used to actually execute the equipment for precipitation and injection of the chemical water stop agent, including a precipitation water pump for starting the precipitation well and an automatic chemical agent injection system.

[0075] Step S5-6, continuously repeat steps S5-1 to S5-5 until all relevant data are within the preset range, ensuring the stability and safety of the foundation pit.

[0076] Application scenario:

[0077] Step S1: In the peripheral zone of the foundation pit, according to the geological structure and hydrogeological conditions of the fully weathered, strongly weathered and moderately weathered granite layer, two foundation pit areas are selected respectively, and dewatering wells are arranged respectively.

[0078] Among them, the first area adopts pipe well dewatering, a total of 55 first area dewatering wells are arranged, the well spacing is 10-15m, the well depth is 28m, the pump capacity is 5-15m 3 / h; the center point of the first area dewatering well is 2m away from the outer edge line of the supporting structure, which can be adjusted according to the actual situation during the specific construction period, the type of the first area dewatering well is well pipe type, the dewatering well is arranged inside the foundation pit, the well spacing is 30m; the observation well is arranged outside the foundation pit, the spacing is 50m. The dewatering well adopts the same structure as the dewatering well in the previous text. The relative positions of the dewatering well and the observation well are not specifically required, and they are adjusted according to the actual situation during the construction period, and the setting position shown in Figure 3 can be used. The arrangement interval of the observation well is also not specifically required, and one observation well can be arranged beside 3-5 catchment wells. The dewatering wells are uniformly distributed in the middle part of the foundation pit.

[0079] The second area adopts pipe well dewatering, a total of 42 second area dewatering wells are arranged, the well spacing is 10-15m, the well depth is 28m, the pump capacity is 5-15m 3 / h; the center point of the first area dewatering well is 2m away from the outer edge line of the supporting structure, which can be adjusted according to the actual situation during the specific construction period, the type of the first area dewatering well is well pipe type, the dewatering well is arranged inside the foundation pit, the well spacing is 30m; the observation well is arranged outside the foundation pit, the spacing is 50m.

[0080] As shown in Figure 4, the steps of constructing the dewatering well are as follows:

[0081] Step 1, construction preparation, including:

[0082] Step 1-1, make construction temporary fence and various warning signs;

[0083] Step 1-2, connect the temporary circuit and water pipe for construction;

[0084] Step 1-3, find out the underground pipelines and underground structures.

[0085] Step 2, set the position of the dewatering well, including:

[0086] Step 2-1, measure and mark the points;

[0087] Step 2-2, check;

[0088] Step 2-3, dig a pit.

[0089] Step 3, bury the steel casing and build the mud pool.

[0090] Step 4, set up the drilling rig and adjust, including:

[0091] Step 4-1, align the drilling rig with the well site;

[0092] Step 4-2, adjust the drilling rig level and verticality;

[0093] Step 4-3, check the drill bit diameter.

[0094] Step 5, drill to the designed depth.

[0095] Step 6, change the mud and check the hole.

[0096] Step 7, lower the well pipe and fill the filter material.

[0097] Step 8, wash the well, supplement the filter material, and seal the upper well;

[0098] Step 9, determine whether the setting of the dewatering well will affect traffic: if it affects traffic, proceed with Step 9-1 to make a buried dewatering well; and proceed with Step 9-2 to make an underground drainage branch; if it does not affect traffic, proceed with Step 10.

[0099] Step 10, install the water pump and perform water pumping.

Claims

1. A foundation pit intelligent dewatering and water stopping method, characterized in that: The method comprises the following steps: Step S1, dewatering: multiple dewatering wells are set up around the foundation pit; dewatering pumps are set up in the dewatering wells; the water level in the dewatering wells is lowered to a preset position by the dewatering pumps; Step S2, drainage: a water collection system is set up at the bottom and side walls of the foundation pit; the water collection system includes a water collection well and a water collection pipe; the water inside the foundation pit is drained through the water collection system; Step S3, water blocking: setting up a groundwater blocking barrier around the foundation pit to prevent groundwater outside the foundation pit from flowing into the foundation pit; Step S4, water blocking: setting a water-stop curtain around the foundation pit to block the flow of water between the inside and outside of the foundation pit; Step S5, monitoring the well water level and initiating emergency measures: when the well water level exceeds a preset safety range or the foundation pit stability index decreases, activating the automatic emergency measures system; activating the automatic emergency measures system includes activating a dewatering pump to dewater until the water level reaches the designed water level; Step S1 includes: the depth, location and spacing of the precipitation wells are determined based on a groundwater flow model and a lake water level dynamic change model: Step S1-1, determining the depth of the precipitation well according to the groundwater flow model, includes: according to the groundwater flow model, the depth of the precipitation well must reach the aquifer to control the groundwater level in the foundation pit area; the depth of the precipitation well is determined based on the annual average groundwater level, seasonal fluctuations, and groundwater flow direction and velocity; Step S1-2, arranging the positions of the precipitation wells according to the groundwater flow model, includes: arranging the positions of the precipitation wells based on the groundwater flow direction and velocity, and arranging the precipitation wells on the main groundwater flow path to enhance precipitation efficiency; Step S1-3, determining the spacing of the precipitation wells based on the groundwater flow model, includes: the spacing of the plurality of precipitation wells is determined based on the groundwater flow model, the plurality of precipitation wells are arranged to cover the entire foundation pit area, the plurality of precipitation wells are independent of each other, and the groundwater level in the entire foundation pit area can be uniformly lowered; Step S1-4, determining the depth of the precipitation well according to the lake water level dynamic change model, includes: according to the seasonal and interannual changes in the lake water level, the depth of the precipitation well needs to adapt to the groundwater pressure during the period of the highest lake water level, so as to be able to control the water level inside the foundation pit during the period of the highest lake water level; Step S1-5, determining the location of the precipitation well according to the lake water level dynamic change model, includes: arranging the precipitation well on a side close to the lake or water body according to the lake water level dynamic change model, so as to control the situation where the groundwater level rises due to the increase of the lake water level; Step S1-6, determining the spacing of the dewatering wells based on the lake water level dynamic change model, includes: based on the dynamic change of the lake water level, the spacing of the plurality of dewatering wells is set according to the lake water level change and the flow direction of the groundwater, so as to control the groundwater level in the foundation pit area during the peak period of the lake water level; The well water level monitoring in step S5 further includes: setting an observation well; the observation well is set outside the foundation pit; a liquid level gauge is set in the observation well for automatically monitoring the water level, and when the water level reaches within ±5 cm of the design water level, the precipitation pump is automatically turned on; Initiating emergency measures in step S5 includes: Step S5-1: installing water level sensors inside and outside the foundation pit, wherein the water level sensors are connected to an automatic monitoring system; the water level sensors and the automatic monitoring system are used to collect real-time water level data and stability indicators inside and outside the foundation pit to evaluate the dewatering effect and the water level stability of the foundation pit; Step S5-2: Install inclinometers and stress sensors in the soil surrounding the foundation pit. Use the inclinometers and stress sensors to monitor displacement and stress changes in the soil and support structure surrounding the foundation pit. Obtain soil mechanical property data through field and laboratory tests, including soil density, porosity, internal friction angle, and cohesion parameters. Use total stations, global navigation satellite systems, and laser scanning measurement technology to obtain deformation data to monitor settlement and horizontal displacement of the foundation pit and its surrounding ground. Step S5-3, collecting relevant data in step S5-1 and step S5-2, wherein the relevant data includes water level data, stability index, soil mechanical property data, and deformation data; Step S5-4, analyzing the relevant data; if the relevant data is within a preset range, repeating steps S5-1 to S5-3; if the relevant data is outside the preset range, proceeding to step S5-5; Step S5-5: when the water level rises or the stability of the foundation pit decreases, the dewatering well is started and the injection amount of the chemical water-stopping agent is increased; Step S5-6, continuously repeating steps S5-1 to S5-5 until all relevant data are within a preset range.

2. The intelligent dewatering and water-stopping method for foundation pit according to claim 1, characterized in that: Step S2 of setting up the water collection system includes: Step S2-1, determining the location of the water collection well; the location of the water collection well is determined according to the water flow direction and concentration area inside the foundation pit; the water collection well is arranged at the low point or water flow convergence area at the bottom of the foundation pit to collect the accumulated water in the foundation pit; Step S2-2, designing the structure of the water collection well: the structure of the water collection well is designed based on the foundation pit depth, geological conditions and expected water volume; the capacity and structural strength of the water collection well are sufficient to cope with the situation of collapse or blockage during precipitation; Step S2-3, setting up water collection pipes, including designing the layout of the water collection pipes: the water collection pipes are set along the bottom and side walls of the foundation pit to form a water flow guidance and collection network; the water collection pipe layout design is designed based on the specific shape and size of the foundation pit and the characteristics of water flow collection; Step S2-4, connecting the water collection well, connecting the water collection pipe to the water collection well, ensuring that the water collected in the water collection well can be transported to a designated discharge location or treatment facility.

3. The intelligent dewatering and water stopping method for foundation pit according to claim 1, characterized in that: Step S3 of setting up a groundwater barrier includes: Step S3-1, selecting a grouting material for forming the groundwater barrier, including: a polymer material or a chemical water-stopping agent; Step S3-2: setting grouting holes, and injecting cement-water-glass slurry into the periphery of the foundation pit through the grouting holes; In step S3-3, the polymer material or chemical water-stopping agent can combine with water molecules in the soil to form a continuous and stable waterproof barrier around the foundation pit, so as to isolate groundwater from entering the foundation pit.

4. The intelligent dewatering and water stopping method for foundation pit according to claim 1, characterized in that: Step S4 of setting a water-stop curtain around the foundation pit also includes: Step S4-1, selecting the material of the water-stop curtain, including polyethylene, polypropylene and polyvinyl chloride; Step S4-2, setting up a water-stop curtain: designing the depth, thickness and arrangement of the water-stop curtain according to the geological conditions, hydrological conditions and construction environment around the foundation pit; the water-stop curtain extends from the bottom of the foundation pit to the stratum of a preset depth to form a water-blocking layer.

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