47 results about "Shallow foundation" patented technology

The invention relates to a deep and thick high-temperature permafrost region highway foundation bearing capacity enhancing method which comprises the following steps: detecting the bearing capacity of a permafrost foundation through static sounding to obtain the spatial distribution characteristics of the bearing capacity of an original-state foundation; the spatial distribution characteristics of the bearing capacity of the undisturbed foundation at least comprise a bearing capacity mean value, a bearing capacity range and a bearing capacity decline ratio; establishing a mapping model at least based on the spatial distribution characteristics of the original-state foundation bearing capacity and the shallow foundation enhancement mode; based on the mapping model, according to the spatial distribution characteristics, obtained through detection, of the original-state foundation bearing capacity, the shallow foundation strengthening mode is determined, and the shallow foundation strengthening mode comprises a structural strengthening measure, a material strengthening measure and a hydrological regulation and control strengthening measure and is used for improving the overall bearing performance of the foundation and restraining permafrost degradation; the structural reinforcing measure at least comprises the steps that a composite bearing structure system is constructed in a shallow foundation, and the mechanical property of the whole foundation is improved by enhancing the bearing capacity of a local area of the foundation.

The invention discloses an in-situ solidification construction method for a highway shallow foundation in a water-rich section of a permafrost region. The in-situ solidification construction method comprises the following steps: step 1, preparation at the early stage of construction; secondly, steel sheet pile enclosure water insulation is conducted; thirdly, in-situ soil solidification construction is conducted; fourthly, dynamic compaction encryption treatment is conducted; step 5, quality detection and molding acceptance inspection; and step 6, subsequent environmental protection and safety guarantee. Three dimensions of a steel sheet pile waterproof technology, a high-weather-resistance composite curing material in-situ curing technology and a dynamic compaction technology are integrated, and a set of systematized and standardized construction scheme is formed. According to the multi-dimensional combined method, the foundation treatment effect is improved, the comprehensiveness and pertinence of construction are enhanced, and a more effective solution is provided for road foundation treatment in the water-rich section of the permafrost region.

The invention discloses a damage assessment method for a shallow-buried foundation bridge under a flood disaster. The method comprises the following steps: constructing a finite element model of the shallow-buried foundation bridge; introducing uncertainty of flood level height, foundation scouring pit length and scouring depth by applying a random Pushover method, obtaining bridge pier top yield displacement of the shallow foundation bridge under multiple groups of scouring working conditions, and calculating first two moments of logarithm of the flood-fighting capacity of the structure to obtain the flood-fighting capacity; performing flood-fighting demand analysis on the response of the shallow-buried foundation bridge in different flood washing environments based on a finite element reliability method; the flood-fighting capacity is compared with demand analysis, the failure probability of the shallow-buried foundation bridge under different working conditions is evaluated, fitting is conducted through the least square method, and a vulnerability curve of the shallow-buried foundation bridge is generated. According to the damage assessment method for the shallow-buried foundation bridge under the flood disaster, the influence of multiple factors such as the flow velocity and the scouring depth on the performance of the shallow-buried foundation bridge can be quantified, and the damage state of each stage of the shallow-buried foundation bridge is effectively assessed.

The present invention discloses a tailings cementation filling construction method applicable to deep wells, and relates to the technical field of deep well filling. The tailings cementation filling construction method applicable to deep wells comprises the following steps: S1, excavating shallow pits around the deep well using a shallow foundation pit excavation method, the number of shallow pits being excavated being 6-8, the depth of the shallow pits being the deepest depth that can be excavated using the shallow foundation pit excavation method, the effective diameter of the shallow pits being equal to the effective radius of the deep well, and the shallow pits being arranged symmetrically relative to the deep well during construction. The tailings cementation filling construction method applicable to deep wells, by digging additional shallow pits and filling them with the sand and soil obtained when digging the shallow pits, the sand and soil filling layer divides the tailings cementation filling layer into two layers, thereby reducing the thickness of the single-layer tailings cementation filling layer, while increasing the exposed area of ​​the upper tailings cementation filling layer, and increasing the stability of the filling material. At the same time, the equipment used for digging and mixing is different and can be carried out simultaneously, and digging additional shallow pits does not affect construction efficiency.

The invention relates to the field of building construction, and discloses a deep and shallow foundation pit group construction deformation prediction control method, which comprises the following steps: acquiring engineering geological parameters of a construction site and foundation pit parameters of a plurality of foundation pits to be constructed; determining a plurality of calculation simulation working conditions; establishing a three-dimensional numerical model by adopting finite element software; simulating the states of the retaining structures of the first foundation pit, the second foundation pit and the third foundation pit in the construction process under different calculation simulation working conditions in the three-dimensional numerical model; deformation data of the adjacent foundation pit limited width soil strip enclosure structure and soil pressure data of the two sides of the adjacent foundation pit limited width soil strip are tested and fed back, and the construction requirement is adjusted according to the data fed back through detection; the three-dimensional numerical model is used for simulating the deformation condition of each enclosure structure of the deep and shallow foundation pit group under different construction sequences, different foundation pit distances and different loads among foundation pits, so that the actual construction requirements are adjusted, and the deformation trend of the enclosure structures in the actual construction process is controlled.

The application discloses a shallow foundation reliability analysis method and device. The method comprises the following steps: selecting a deterministic bearing capacity envelope surface equation of a shallow foundation according to requirements; obtaining a probability single-axis bearing capacity sample set; converting the deterministic bearing capacity envelope surface by using the probability single-axis bearing capacity sample to generate a large number of probability bearing capacity envelope surface samples; setting a load combination sample according to requirements, comparing the load combination sample with the bearing capacity envelope surface sample, and carrying out reliability analysis by combining a performance function and a Monte Carlo simulation. The core of the application is to solve the probability single-axis bearing capacity, combine the deterministic bearing capacity envelope surface equation, construct the probability bearing capacity envelope surface, and carry out the shallow foundation reliability analysis by using the Monte Carlo simulation. The method avoids numerical analysis for different load combinations respectively, greatly improves the calculation efficiency, and is simple in principle and convenient to use, thereby providing an efficient and practical tool for the shallow foundation reliability analysis under complex geological and load conditions.

The invention discloses a shallow foundation reliability analysis method and device. The method comprises the steps that a deterministic bearing capacity envelope surface equation of the shallow foundation is selected according to requirements; obtaining a probability uniaxial bearing capacity sample set; converting the deterministic bearing capacity envelope surface by utilizing the probability uniaxial bearing capacity sample to generate a large number of probability bearing capacity envelope surface samples; setting a load combination sample according to requirements, comparing the load combination sample with a bearing capacity envelope surface sample, and carrying out reliability analysis in combination with a performance function and Monte Carlo simulation. The core of the method is that the probability bearing capacity envelope surface is constructed by solving the probability uniaxial bearing capacity and combining a deterministic bearing capacity envelope surface equation, and the reliability analysis of the shallow foundation is carried out by adopting Monte Carlo simulation. According to the method, the situation that numerical analysis is conducted on different load combinations is avoided, the calculation efficiency is greatly improved, the principle is simple, use is convenient, and an efficient and practical tool is provided for shallow foundation reliability analysis under the complex geology and load conditions.

The invention discloses a method and device for calculating the ultimate bearing capacity of a shallow foundation of a deep replacement soft soil layer. The method comprises the following steps: firstly, constructing a limit failure surface model controlled by a single variable angle alpha according to a foundation, the size of replacement soil and soil layer parameters; then, force and moment balance analysis is conducted on the basis of the limit equilibrium principle, the foundation limit bearing capacity is decomposed into the sum of three subitem bearing capacities of ground overload, in-soil cohesive force and soil dead weight, and the function relation between each subitem bearing capacity and the variable angle alpha is deduced; and finally, establishing a function of the total ultimate bearing capacity relative to the variable angle alpha, and calculating the minimum value through derivation or iteration so as to determine the ultimate bearing capacity of the foundation. According to the method, the complex failure surface model which is more practical is constructed, rigorous mechanical derivation is carried out, the limitation that an existing method is only suitable for the homogeneous foundation or shallow layer replacement condition is solved, and a reliable theoretical basis is provided for foundation bearing capacity calculation of a deep replacement soft soil layer.

The present application relates to a kind of simple calculation method of shallow foundation and clay seabed interface failure time under extreme storm surge action.The technical scheme is: measuring the roughness R of shallow foundation a , making structure;Collecting seabed clay at shallow foundation, carrying out dynamic simple shear test, test structure and the initial undrained shear strength S of clay interface u ;Select and set 0.4S u , 0.6S u , 0.8S u And 1S u As the typical amplitude of extreme storm surge load;Measured structure and the corresponding period number N of clay interface failure;Fitting extreme storm surge load amplitude and period number N logarithmic curve;According to wave force calculation formula, load amplitude is calculated;The amplitude is substituted into logarithmic curve and the corresponding period number N of interface failure and failure time are obtained.The present application can calculate the failure time of shallow foundation and seabed interface under extreme storm surge, provide the time length of shallow foundation against storm surge, determine the stability of shallow foundation, provide feedback for whether the shallow foundation of engineering site needs to be reinforced to resist extreme storm surge.

The utility model discloses a kind of first tunnel after well method foundation pit supporting structures, including underground continuous wall, the underground continuous wall is set in first tunnel after well method tunnel area upper foundation pit and tunnel area foundation pit junction, concrete crown beam is provided on the underground continuous wall, a mortar anchor rod is provided inside the concrete crown beam. The present application is mainly applied to the supporting structure between deep and shallow foundation pits, which can ensure the safety of foundation pit excavation, improve construction efficiency and reduce construction cost.

This invention discloses a method for calculating the bearing capacity of shallow foundations by integrating machine learning and nonlocal algorithms, belonging to geotechnical engineering. 1. The type of foundation soil is determined through indoor triaxial tests; strain-hardening foundation soils are analyzed; 2. Strain-softening foundation soils are analyzed; 3. A finite element model is established for refined simulation, followed by 7. 3. A constitutive model combined with a nonlocal algorithm is used for refined simulation, then proceeds to 4. 4. The influence range (DL) of the shallow foundation analysis is calibrated. f DL is determined by the softening rate control parameter β. f If suitable, proceed to step 7; otherwise, proceed to step 6. Step 6 involves building and training a machine learning agent model to ultimately obtain a suitable deep learning (DL) algorithm. f Shallow foundation analysis was performed with β1 and 7 to obtain the predicted value of the foundation bearing capacity. The present invention uses the above method to achieve efficient inversion of nonlocal parameters, thereby obtaining a reasonable predicted value of the shallow foundation bearing capacity.

The application provides a stability evaluation method based on an envelope surface of a shallow foundation bearing capacity under wave load. The technical scheme is: collecting soil samples on the engineering site and carrying out test calibration of soil parameters; establishing a three-dimensional numerical model based on a modified Cambridge model and calculating the initial bearing capacity of the shallow foundation; selecting and applying representative amplitudes of wave load to the shallow foundation to obtain the horizontal-moment bearing capacity envelope surface under different amplitudes of wave load; calculating the actual horizontal and moment loads borne by the shallow foundation according to the on-site wave load and determining whether the actual horizontal and moment loads are below all the horizontal-moment bearing capacity envelope surfaces to determine the stability of the shallow foundation. The application can truly simulate the working condition of the shallow foundation bearing the combined action of horizontal and moment cyclic loads in the marine environment, calculate the bearing capacity envelope surface of the shallow foundation under different amplitudes of wave load, determine whether the shallow foundation has a safety hazard, and provide a reference for whether reinforcement treatment measures need to be taken for the in-situ shallow foundation.

This invention relates to the field of road construction technology and discloses a reverse-construction cut-and-cover method for converting a highway into a bridge. The method includes the following steps: construction preparation and half-width closure, integrated pile-column construction, cap beam and superstructure construction, traffic diversion, reverse-construction cut-and-cover of the soil under the bridge, pier appearance treatment, and repeated construction. This invention directly constructs an integrated pile-column structure on the existing road surface, completely eliminating the need for deep foundation pit excavation (over 9 meters). It transforms high-risk deep foundation pit projects into low-risk shallow foundation pit projects, effectively avoiding safety accidents such as foundation pit collapse and roadbed slippage. Simultaneously, it eliminates the interference of deep foundation pit construction on adjacent highways, ensuring the safety of both construction personnel and passing vehicles.

The invention provides an anti-seismic testing method and system for a railway gravity type pier shallow foundation, and relates to the technical field of anti-seismic testing. The method comprises the steps that a plurality of test models of the railway gravity type pier shallow foundation are manufactured, and a quasi-static test is carried out; acquiring side substrate pressure of multiple times of displacement loading of the multiple test models; according to the side base pressure, the base lift-off amount is determined; acquiring the horizontal displacement and the horizontal load of the pier top subjected to multiple times of displacement loading of the plurality of test models; acquiring a force-displacement hysteresis curve of the plurality of test models; determining an equivalent stiffness attenuation gradient; when the quasi-static test is finished, crack parameters of the multiple test models are obtained; determining a crack energy dissipation ratio; and the anti-seismic performance of the railway gravity type pier shallow foundation is determined. According to the device and the method, the anti-seismic performance of the railway gravity type pier shallow foundation can be tested according to the foundation lift-off amount, the equivalent stiffness attenuation gradient and the crack energy dissipation proportion, and the accuracy and comprehensiveness of the anti-seismic test are improved.

The utility model relates to the technical field of buildings, and discloses a shallow foundation building deviation rectifying and reinforcing structure which comprises a reinforcing base and further comprises supporting plates fixed to the two sides of the top of the reinforcing base, the rear sides of the opposite sides of the two supporting plates are rotationally connected with a two-way lead screw, and one end of the two-way lead screw is fixedly connected with a first rotating disc. And moving frames are arranged on the two sides of the top of the reinforcing seat. A two-way screw rod can be rotated by rotating a first rotating disc, a movable frame drives two clamping rings to relatively move in cooperation with a threaded sleeve, if a supporting column needing deviation rectification is round, an L-shaped plate can be taken out from the interior of a clamping groove, then the two clamping rings abut against the surface of the supporting column, and first-layer reinforcement and correction are conducted through screws on the two sides; and then a second rotating disc is rotated to enable a screw rod to rotate in a moving frame, and a connecting ring is matched to move to abut against the surface of the supporting column for reinforcement and correction, so that the size of the supporting column can be corrected according to needs for adjustment and reinforcement.

The utility model provides a lifting platform device for a stage, and relates to the field of stage mechanical equipment. The device comprises a mounting base and a table top, guide mechanisms and a flexible column jacking driving mechanism are arranged between the mounting base and the table top, the flexible column jacking driving mechanism is arranged between a pair of symmetrically arranged guide mechanisms, and the flexible column jacking driving mechanism drives the table top to do lifting motion; the flexible column jacking driving mechanism comprises a short connection column, a jacking chain set, a pin gear box, a double-shaft gear motor and a storage box, a protection mechanism is installed on the outer side of the table top, and a stroke limiting switch and a fire breaker are fixedly installed on the installation base. A flexible column jacking and lifting mode is adopted, the lifting platform has the advantages of being shallow in foundation pit, high in speed, large in stroke, heavy in load and high in transmission precision and structural stability, the highest working elevation of the platform face extends out of the stage by 2 m, and the platform face can serve as a front extension part of the stage. A guide mechanism is adopted for guiding, the stability of the lifting process is improved, and the lifting safety is improved through a stroke limiting switch.

The utility model discloses an ejection type lifting stage which comprises a frame body, an ejection table top and a driving device, the driving device comprises a winch and a servo motor, the ejection table top is arranged on the frame body in a lifting mode, the driving device is arranged on one side of the frame body, a lower pulley block is fixedly arranged at the bottom of the frame body, and an upper pulley block is fixedly arranged at the top of the frame body. The output end of the winch is connected with a steel wire rope set, and the steel wire rope set extends out of the winch, sequentially penetrates through the lower pulley block and the upper pulley block and then is connected with the ejection tabletop. Through driving control of the servo motor and combination of the structural design of the frame body, the rapid ejection performance effect can be achieved in the shallow foundation pit, and the shocking visual feeling is brought to audiences; the device is controlled by a servo motor, the speed is adjustable, the ejection height of performers can be adjusted at any time, and the device further has a lifting use function, is suitable for performers with different weights, and is easy to operate, convenient to maintain and high in use safety.

The invention relates to the technical field of lifting equipment, and discloses a driving mechanism suitable for a shallow foundation pit lifting platform. The mechanism comprises a hydraulic cylinder thrust unit, a diagonal bridging stabilizing mechanism and a compression energy storage spring. The hydraulic cylinder thrust units and the cross bridging stabilizing mechanisms are arranged in pairs, the ends of piston rods of the hydraulic cylinder thrust units and the cross bridging stabilizing mechanisms are coaxially hinged to the lifting platform through hinge seats, horizontal component force of hydraulic cylinders is converted into structural internal force, and the horizontal component force counteracts the structural internal force. And the compression energy storage spring is arranged near a hinge point of the cross bridging stabilizing mechanism. The end of a piston rod of the hydraulic cylinder is coaxially hinged to the cross bridging, the inclined hydraulic cylinder is used for directly pushing the cross bridging, and large-stroke lifting of the lifting platform in the shallow foundation pit is achieved through the cross bridging structure. The initial thrust of the inclined hydraulic cylinder is reduced through the compression energy storage spring, and the defects that the horizontal component force of the inclined hydraulic cylinder is seriously amplified and the vertical component force is small when the mechanism is in a contraction state are overcome.

The invention discloses a permeable stratum in-water shallow foundation template cofferdam system and a construction method, and the system comprises bottom sealing cushion layer concrete at the bottom of a foundation trench, longitudinal I-shaped steel 1 arranged on a top terrace of the foundation trench, and supporting units 2 arranged on two groups of longitudinal I-shaped steel 1, the outer mold unit 3 and the inner mold unit 4 are supported and fixed through the supporting unit 2, and the clay filling layer is arranged between the outer mold unit 3 and the inner mold unit 4. According to the cofferdam system, the inner mold unit 4 serves as a formwork structure for construction in a foundation pit, the outer mold unit 3 serves as an anti-scouring structure to protect internal filling clay, the space between the double-layer steel formworks is filled with the clay, the clay is compacted, and the steel formwork-clay-steel formwork cofferdam system is formed; clay is filled between the outer mold unit 3 and the inner mold unit 4, compactness is improved through layered compaction, the water stopping effect is enhanced, and the problems that in the prior art, procedures are complex and tedious, the construction period is long, and cost is high due to the fact that a cofferdam is constructed firstly and then a formwork is erected are solved.

The invention discloses a foundation pit retaining wall structure and a construction method thereof. The retaining wall structure comprises a concrete cushion layer, a prefabricated concrete bottom plate and a GRC plate retaining wall. The precast concrete bottom plate is arranged on the concrete cushion layer, a reserved groove is formed in the precast concrete bottom plate, and a reserved anchor bar hole is formed in the bottom side of the reserved groove; the GRC plate retaining wall is formed by connecting a plurality of GRC plate bodies, the adjacent GRC plate bodies are connected through clamping groove type rabbets, reinforcement cages are arranged in the GRC plate bodies, anchor bars are pre-buried at the bottoms of the GRC plate bodies, the lower portions of the GRC plate bodies are arranged in the reserved grooves, the anchor bars at the bottoms of the GRC plate bodies are inserted into the reserved anchor bar holes, and the GRC plate retaining wall is formed by connecting the GRC plate bodies. And water stop structures are arranged in the reserved groove and the slab joints of the GRC slab retaining wall. Synchronous construction of the deep foundation and the shallow foundation is achieved, the construction period is shortened, the comprehensive cost is reduced, and meanwhile the waterproof performance and the structural safety of the retaining wall are improved.

The invention relates to a modular rapid building construction method for a nonlinear S-shaped wide and thick plate factory, which comprises the following steps of: dividing a process production line into a plurality of construction areas by taking a movable ground assembled jig frame as a precision control platform; the parallel flow construction that main line deep foundations are conducted first and auxiliary line shallow foundations are conducted later is synchronously executed in all the areas, and an operation cycle of opening and closing combination and vertical crossing is formed through installation with a workshop steel structure; and through overall three-dimensional measurement and adjustable interface positioning, precise closing is carried out on an S-shaped turning and linear section equipment foundation interface, and finally synchronous, precise and rapid construction of the equipment foundation and the steel structure under nonlinear arrangement is achieved.

The utility model relates to the technical field of road and bridge engineering, in particular to a railway bridge pier shallow foundation structure which comprises a bottom layer foundation, a top layer foundation and a pier body, the cross section area of the bottom layer foundation is larger than that of the top layer foundation, and the cross section area of the top layer foundation is larger than that of the pier body. The bottom layer foundation, the top layer foundation and the pier body are all composed of steel bar grids and concrete, the steel bar grids are composed of transverse steel bars and longitudinal steel bars which are bundled together, and a reinforcing layer is further arranged on the transverse steel bars of the bottom layer foundation. The bottom-layer foundation, the top-layer foundation and the pier body form a stepped structure, the bottom-layer foundation serves as a main bearing layer and effectively disperses stress of the base, the top-layer foundation is connected with the bottom layer through stepped transition to form a stress diffusion gradient layer, and the transverse steel bars and the longitudinal steel bars form a bidirectional reinforcement structure system. The longitudinal steel bars achieve reinforcement ratio gradient transition through step type truncation, the stability and the bearing capacity can be improved, and convenience is provided for construction and maintenance.

The invention relates to the technical field of stage devices, in particular to a shallow foundation pit large-stroke heavy-load self-guiding lifting system which comprises a top plate device, a cross bridging device and a bottom plate device which are sequentially connected, the cross bridging device comprises a plurality of crossed double-arm units which are sequentially hinged, and it is guaranteed that a cross bridging hinge shaft is sheared on the two sides; the bearing capacity, deformation precision control and structural stability are improved; two hydraulic cylinders are symmetrically mounted on each layer of crossed double-arm unit, so that a statically indeterminate structure stable form is realized, and better deformation control capability, lateral stability and vertical bearing capability are achieved; the multi-layer cross double-arm connecting mode has the autonomous guiding capacity, stable lifting guiding can be achieved without additional guiding devices and lifting systems, the lifting height can reach 10 times or above of the height of the structure, the requirement for the large stroke of a shallow foundation pit is met, meanwhile, field installation and debugging and system integration are avoided, cost is reduced by 20% or above, and the cost is reduced by 20% or above. The lifting system is flexible in arrangement, and multi-scene application is achieved.

The present application relates to the technical field of modular building structure, and particularly relates to a modular building based on a CLT-SMC composite system and an assembly method, which adopts an SMC steel structure frame as a core bearing layer, adopts a CLT wood wallboard as a surrounding function layer, and forms a composite bearing surrounding module by fixing the two through decorative connecting pieces and glued wood; the module is prefabricated in a factory and is integrated with water and electricity pipelines, degradable sealing materials, heat storage phase change materials and detachable lightweight partition walls; on site, shallow foundations and vibration isolation supports are used, horizontal splicing and longitudinal stacking of the module are realized through horizontal connecting plates, top corner pieces and high-strength bolts, and solar photovoltaic components are installed; after use, the building can be disassembled in reverse order, and the components can be reused after repair. Lightweight structure, flexible function conversion, rapid construction and low interference are realized, carbon emissions and ecological impact are significantly reduced, and full life cycle reversible circulation is supported.

The invention relates to the technical field of coal mine tunnel support and water disaster prevention and control, and discloses a bolting-grouting water plugging support method for a water-rich fault tunnel, which comprises the following steps: forming a shallow foundation support along with tunneling construction of a common anchor rod; a deep reinforcing anchor rod is constructed in the first lagging aging to form a deep reinforcing support; grouting anchor rods are arranged; and after second lagging aging after tunneling is finished, modified cement grout is prepared for grouting plugging, and the modified cement grout is prepared from Portland cement, water and a composite additive containing aluminate clinker, polyacrylamide and the like. According to the method, through a space-time cooperative control strategy of shallow surface protection deep suspension lagging grouting, repairing is carried out in the optimal window period of fracture development by using the rheological characteristics of surrounding rock; by matching with modified slurry with quick-setting early strength and underwater dispersion resistance, effective cementing and water stopping of broken surrounding rocks in a flowing water environment are realized, the water inflow of a roadway is reduced, and deformation of the surrounding rocks is controlled.

The process of improving thick soft and loose soils using deep soil-cement footings in combination with sand or cemented sand impact compaction footings is to address the weaknesses of DSM footings and also to increase the load-bearing capacity of the ends of single compaction footings in soft and loose soils. This system improves the mechanical behavior of the subgrade by longitudinally integrating the two types of footings. Depending on the type and thickness of the loose layers and the degree of soil consistency, four types of composite systems can be used to improve the ground, increase the bearing capacity, reduce the settlement of shallow foundations, and improve the stability of the bed in difficult coastal conditions:\n1. Sand impact compaction foundation + soil-cement foundation\n2. Cemented sand impact compaction foundation + soil-cement foundation\n3. Thick sand impact compaction foundation + soil-cement foundation\n4. Thick cemented sand impact compaction foundation + soil-cement foundation.\nThe choice of the type of system depends on the characteristics of the structure, the number of stories, and the amount of loads on the bed. It is also possible to increase the strength of the base by combining different base layers, either in the normal or cemented state.

This invention discloses a zoned active control support structure and construction method for shallow foundation pits, belonging to the field of foundation pit construction technology. It includes a retaining structure, an internal support structure, a monitoring system, and an inclinometer connected to the existing underground structure. A grouting device is installed on the top of the retaining structure facing the existing underground structure. The retaining structure is divided into active zones facing the existing underground structure and underground continuous walls facing other areas. The active zones are further divided into multiple adjacent zones. The support structure includes several horizontal support systems. At the corresponding positions of the active zones, each horizontal support system includes multiple servo internal supports positioned between the underground continuous walls and the active zones. The inclinometer monitors soil deformation in real time, and then controls the corresponding servo internal supports to output displacement, thereby moving the active zones forward and actively controlling soil deformation.

The invention provides a composite pile group ground anchor system of a pipe pushing machine and an installation method of the composite pile group ground anchor system. The installation method comprises the steps that a shallow foundation pit is excavated; the steel pipe piles are driven into the bottom of the shallow foundation pit and are transversely and longitudinally distributed in multiple rows and columns; the multiple sets of reinforcement cages are arranged on the periphery of the space formed by the steel pipe piles, and a plurality of stirrups are arranged on the periphery of each set of reinforcement cages at intervals; concrete is poured into the shallow foundation pit; the ground anchor plate is arranged on the concrete, and the steel pipe piles penetrate through holes in the ground anchor plate; the pipe pushing machine is located on the ground anchor plate, the center lines of the pipe pushing machine and the ground anchor plate are aligned, the edge of a base of the pipe pushing machine is welded to the ground anchor plate, and then the ground anchor plate and the steel pipe pile are welded and fixed through a fixing piece; and the steel pipe piles, the reinforcement cage, the concrete, the ground anchor plate and the pipe pushing machine base form a resistance system, and the composite pile group ground anchor of the pipe pushing machine is installed. The composite pile group ground anchor system of the pipe pushing machine is formed through the method. A large resistance system is formed, and the strength of a ground anchor system is improved.

The application discloses a kind of early dismantling construction methods of retaining structure of near subway group pit construction, comprising: first batch deep foundation pit is constructed by using jump pit construction along the length direction of trestle, after first batch deep foundation pit construction is completed to basement roof, roof is changed to trestle and retaining structure, first batch shallow foundation pit and the earthwork excavation and support of remaining deep foundation pit in the same direction, structure construction that are opposite to first batch deep foundation pit are started;When remaining deep foundation pit in the same direction is constructed to foundation bottom plate, the earthwork excavation and support of deep foundation pit relatively far away from the side of trestle, structure construction are carried out, when construction is to B1 floor, the earthwork excavation and support of second batch shallow foundation pit adjacent to first batch shallow foundation pit, structure construction are carried out;When second batch shallow foundation pit construction completes B1 layer foundation bottom plate, temporary steel slope changes support and side wall, the earthwork excavation and support of remaining shallow foundation pit, structure construction are carried out. Construction trestle can be removed in advance, main structure early construction, early connection can be effectively realized, so as to ensure that structure is completed in advance.