Support system and support method for coastal facies sludge geology crown beam construction

Abstract

The invention discloses a supporting system and method for coastal facies sludge geology crown beam construction, and relates to the technical field of coastal facies sludge geology crown beam construction supporting, and the technical scheme is that the supporting system comprises an outer supporting system, an inner supporting system and a hydraulic jack; the outer supporting system comprises two outer protection plates which are symmetrically arranged on the two sides of the crown beam; the inner supporting system comprises a plurality of evenly-distributed supporting beams arranged between the tops of the two outer protection plates and two symmetrically-arranged inner protection plates arranged on the two sides of the top beam. And a plurality of uniformly distributed hydraulic jacks are arranged between the outer protection plate and the inner protection plate. The device has the beneficial effects that through the synergistic effect of the outer supporting system, the inner supporting system and the hydraulic jack, a space stress system is formed; the outer supporting system effectively resists horizontal soil pressure, H-shaped steel diagonal bracings of the inner supporting system control rebound of the base, and a hydraulic jack dynamically balances uneven loads.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of construction support of crown beam in coastal mud geology, and particularly relates to a support system and a support method for construction of crown beam in coastal mud geology. BACKGROUND

[0002] When the crown beam is constructed in the coastal mud geology, the traditional crown beam construction method is prone to problems such as soil slip, deformation of formwork support setting and even collapse, because the geology is weak, the water content is high, the bearing capacity is low and the mud is easy to flow. When the crown beam is constructed in the coastal mud geology, the traditional support method is often difficult to meet the stability requirement, because the mud layer has characteristics such as high water content, low bearing capacity, high compressibility and strong rheological property. The muddy soil is prone to lateral flow, basement uplift or piping penetration after being disturbed, which causes deformation or even failure of the support structure, and seriously affects the construction safety and engineering progress.

[0003] The prior art mainly has the following limitations: 1. Deficiency of conventional support system: The steel sheet pile support is prone to deflection in deep mud, and the inter-pile occlusion is not tight enough to cause leakage problems. The cement-soil mixing pile is affected by organic matter in the mud, and has poor solidification effect, so that the pile strength is difficult to guarantee. The soil nailing wall support often has problems such as surface cracking and soil nailing pulling out, because the soil has poor self-stability.

[0004] 2. Influence of water environment: The groundwater level is high in the coastal area, and the groundwater level is periodically fluctuated by the tide effect, which produces dynamic water pressure and further aggravates the seepage risk of the foundation pit. The seepage coefficient of the mud is low, and the effect of conventional dewatering measures is limited. Long-term pumping of water can easily cause surrounding ground subsidence, which threatens the safety of adjacent buildings.

[0005] 3. Deformation control problem: The rheological property of the mud causes continuous deformation of the support structure, and the traditional rigid support cannot adapt to it. The uneven settlement of the crown beam easily causes stress concentration of the support system, which causes damage to the connecting nodes. The uneven settlement or horizontal displacement causes the crown beam to crack, which further affects the stability of the overall support system.

[0006] 4. Defects in construction technology: Large mechanical equipment has difficulty in operation on soft ground, which easily causes disturbance of the foundation.

[0007] In view of the above problems, there is an urgent need for a crown beam construction support method suitable for coastal mud geology, which is efficient, stable and has strong adaptability, can effectively control the deformation under soft soil conditions, and ensure the construction safety of foundation pit excavation and crown beam pouring. SUMMARY

[0008] In order to achieve the above-mentioned purpose of the application, aiming at the above-mentioned technical problems, the application provides a supporting system and a supporting method for coastal facies silt geological crown beam construction.

[0009] The technical scheme is a supporting system for coastal facies silt geological crown beam construction, comprising an outer supporting system, an inner supporting system and a hydraulic jack. The outer supporting system comprises two symmetrically arranged outer protection plates on both sides of the crown beam. The inner supporting system comprises a plurality of uniformly distributed supporting beams arranged between the top portions of the two outer protection plates and two symmetrically arranged inner protection plates on both sides of the crown beam. The plurality of uniformly distributed hydraulic jacks are arranged between the outer protection plates and the inner protection plates. The outer protection plate comprises an outer protection vertical plate, an outer protection inclined plate and an outer protection horizontal plate which are connected with each other. The inner protection plate is arranged in an L shape and comprises an inner protection vertical plate and an inner protection horizontal plate. The supporting beam adopts H-shaped steel.

[0010] The inner walls of the two inner protection plates are matched with the crown beam.

[0011] The two outer protection horizontal plates and the two inner protection plates are located on both sides of the top portions of the steel pipe piles.

[0012] The hydraulic jacks are arranged between the outer protection vertical plate and the inner protection vertical plate and between the outer protection inclined plate and the inner protection vertical plate. The fixed ends of the hydraulic jacks are fixedly connected with the outer protection vertical plate and the outer protection inclined plate, and the telescopic ends of the hydraulic jacks are fixedly connected with the outer wall of the inner protection vertical plate.

[0013] The outer protection inclined plate is arranged in an inclined manner. The supporting beams are horizontally supported between the two outer protection vertical plates. The supporting beams adopt H400*400*13*21 type and are arranged at an interval of 3.0 m to provide internal prestress. The hydraulic jacks adopt 200t level.

[0014] An outer supporting steel pipe inclined support is arranged on the inner side of the outer wall of the end portion of the outer protection plate, the outer supporting steel pipe inclined support adopts φ219*10mm steel pipe, penetrates the silt layer into the stable bearing layer at an inclination angle of 55°±5°, is arranged at an interval of 2.5 m to form external anti-sliding constraint, the upper end is connected by a flange plate, and the lower end is provided with an enlarged bearing plate to reduce the foundation stress.

[0015] The supporting method based on the supporting system for coastal facies silt geological crown beam construction comprises the following steps. S1, site investigation and measurement lofting Before construction, the engineering geological investigation is carried out to find out the thickness of silt layer, physical and mechanical indexes and groundwater conditions; total station is used for measurement and lofting to establish construction control network; The concrete cushion is poured and compacted by using flat plate vibrator; S2, support system installation In the area where the steel pipe pile construction is completed and the corbel construction is needed, excavation is carried out to the elevation below the corbel construction; In the corbel excavation area, the outer support system of the corbel construction support system is set, and a support beam support is set at the upper part to ensure the stability of the support system; the support beam is hoisted by two truck cranes; the H-shaped steel support beam is prefabricated in the factory, and the end is welded with a reinforcing rib plate; the end of the inner protective plate is connected with the corbel embedded part by high-strength bolts; The inner support system is set on both sides of the steel pipe pile to increase the overall support stability and provide a force point for the hydraulic jack support; The hydraulic jack is set between the outer support system of the corbel excavation area and the inner support system of the corbel formwork; the hydraulic jack applies axial load by uniform speed of the piston rod, and the pressure value is fed back in real time by the digital instrument to ensure that the pressure reaches the set value; S3, corbel main body construction Steel reinforcement engineering The main reinforcement is connected by straight thread sleeve, and the waist reinforcement is fixed by welding; Formwork engineering The formwork is assembled by using shaped steel formwork, and closed-cell foam sealing strips are pasted at the formwork joint; φ16 opposite-pull bolts are used for formwork reinforcement; after the formwork is installed, the verticality is detected; Concrete pouring The concrete is poured by using a truck pump in layers, and the vibration is carried out by using φ50 insertion type vibrating rod; immediately after pouring, geotextile is covered for moisture curing.

[0016] The pressure of the hydraulic jack is applied by grading loading, including the following stages: Initial pre-tightening: 30% of the design axial force is applied, and the pressure is stabilized for 10 minutes; Secondary loading: increased to 60% of the design axial force, and the pressure is stabilized for 15 minutes; Third loading: increased to 90% of the design axial force, and the pressure is stabilized for 20 minutes; Final loading: 100% of the design axial force is reached, and the pressure is stabilized for 30 minutes.

[0017] After the corbel concrete strength reaches the design requirement, the pressure of the hydraulic jack is released first, the hydraulic jack is removed, the inner support system inside the corbel and the corbel formwork are removed, the support beam support at the upper part of the outer support system is removed, and finally the outermost outer support system is removed.

[0018] Before the prestressed steel strand of the corbel is tensioned, the tensioning slope is ground in advance, the 180*310*20 steel base plate is placed, and then the anchorage device is installed for tensioning.

[0019] The φ219*10mm outer support steel pipe inclined support is arranged outside the corbel, the outer support steel pipe inclined support penetrates the sludge layer into the stable bearing layer at an inclination of 55°±5°, the horizontal spacing is 2.5m, the upper end is connected by a flange plate, and the lower end is provided with an enlarged bearing plate to reduce the foundation stress.

[0020] The support beam adopts an H400*400*13*21 type, is arranged at an interval of 3.0m, and provides internal prestress; and adjustable supports are arranged at the support ends and are fixed with the corbel formwork support.

[0021] The technical scheme provided by the embodiment of the present application has the beneficial effects that: the scheme aims at the technical problems of large deformation, poor stability and weak adaptability of the traditional supporting method in the coastal facies sludge geology, and provides a supporting system and a supporting method for the construction of the corbel in the coastal facies sludge geology, and a spatial stress system is formed through the synergistic effect of the outer support system, the inner support system and the hydraulic jack. The outer support system effectively resists the horizontal earth pressure, the H-shaped steel of the inner support system controls the base rebound, and the hydraulic jack dynamically balances the uneven load. The actual engineering monitoring data shows that the system can effectively control the horizontal displacement of the corbel within a safe range.

[0022] The successful application of the construction method creates a brand-new construction method for similar corbel supporting construction, adopts outer support+hydraulic jack+inner support supporting, solves the construction difficulty of the corbel caused by the excessive fluidity of the sludge soil, provides safe and reliable construction conditions for the construction of the corbel, reduces large-area earth excavation, has low cost, short construction period and low construction difficulty, greatly reduces the water and soil loss caused by the gap between piles, uses the least materials, completes a solid and stable construction system, the tools and materials used for supporting can be repeatedly used, effectively reduces the waste of materials, reduces the engineering cost, and meets the green construction requirements.

[0023] The construction method is suitable for the construction of the corbel supporting in the coastal facies sludge geology, especially for projects with poor geology, large soil fluidity, complex geological conditions in the excavation range, and unsuitable for large-area excavation for corbel supporting, fully embodies the demonstration role of the development of building technology relying on project entities, and has good popularization and application value. The supporting method realizes the comprehensive benefits of safety control, economic rationality and environmental friendliness through technical innovation, and provides a reliable technical solution for engineering construction under the condition of coastal facies sludge geology. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The overall structure of the embodiment of the present application is shown Figure One.

[0025] Figure 2 Overall structure diagram of an embodiment of the present application Figure Two .

[0026] Figure 3 Overall structure diagram of an embodiment of the present application Figure Three .

[0027] Wherein, the reference signs are: 4, hydraulic jack; 100, crown beam; 1, outer protective plate; 2, support beam; 3, inner protective plate; 101, outer protective vertical plate; 102, outer protective inclined plate; 103, outer protective horizontal plate; 301, inner protective vertical plate; 302, inner protective horizontal plate; 200, steel pipe pile. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. Of course, the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0029] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0030] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for description purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0031] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] Embodiment 1 Referring to Figures 1 to 3 The present application provides a support system for construction of a coastal mud geological crown beam, comprising an outer support system, an inner support system and a hydraulic jack 4; The outer support system comprises two symmetrically arranged outer protective plates 1 on both sides of the crown beam 100; The inner support system comprises a plurality of evenly distributed support beams 2 arranged between the top of the two outer protective plates 1 and two symmetrically arranged inner protective plates 3 on both sides of the crown beam 100; A plurality of evenly distributed hydraulic jacks 4 are arranged between the outer protective plates 1 and the inner protective plates 3; The outer protective plate 1 comprises an outer protective vertical plate 101, an outer protective inclined plate 102 and an outer protective horizontal plate 103 connected to each other; The inner protective plate 3 is arranged in an L shape and comprises an inner protective vertical plate 301 and an inner protective horizontal plate 302; The support beam 2 is made of H-shaped steel.

[0033] The inner walls of the two inner protective plates 3 are matched with the crown beam 100.

[0034] The two outer protective horizontal plates 103 and the two inner protective plates 3 are located on both sides of the top of the steel pipe pile 200.

[0035] Hydraulic jacks 4 are arranged between the outer protective vertical plate 101 and the inner protective vertical plate 301, and between the outer protective inclined plate 102 and the inner protective vertical plate 301; The fixed end of the hydraulic jack 4 is fixedly connected with the outer protective vertical plate 101 and the outer protective inclined plate 102, and the telescopic end of the hydraulic jack 4 is fixedly connected with the outer wall of the inner protective vertical plate 301.

[0036] The outer protective inclined plate 102 is arranged obliquely; The support beam 2 is horizontally supported between the two outer protective vertical plates 101; The support beam 2 is of H400*400*13*21 type and is arranged at an interval of 3.0 m to provide internal prestress; The hydraulic jack 4 is of 200t level to realize dynamic force system balance.

[0037] The outer support steel pipe inclined support is arranged inside the outer wall of the end portion of the outer protection plate 1, the outer support steel pipe inclined support adopts a φ219x10mm steel pipe, penetrates the sludge layer into the stable bearing layer at an inclination of 55°±5°, is arranged at an interval of 2.5m, forms an external anti-sliding constraint, the upper end is connected by a flange plate, and the lower end is provided with an enlarged bearing plate to reduce the stress of the foundation.

[0038] The supporting method of the supporting system based on the crown beam construction of the coastal facies sludge geological crown beam construction, comprising the following steps: S1, site investigation and measurement lofting Before construction, the engineering geological re-investigation is carried out, the thickness of the sludge layer, the physical and mechanical indexes and the underground water conditions are ascertained, the total station instrument is used for measurement lofting, and the construction control network is established; Pouring concrete cushion, using flat plate vibrator to vibrate and compact; S2, supporting system installation The steel pipe pile 200 is constructed, the crown beam 100 construction area needs to be excavated, and the excavation is performed to the crown beam construction elevation; The outer support system of the crown beam construction supporting system is arranged in the crown beam 100 excavation area, and a support beam 2 is supported at the upper portion to ensure the stability of the supporting system; the support beam 2 is hoisted by two automobile cranes; the H-shaped steel support beam is prefabricated in the factory, and the end portion is welded with a reinforcing rib plate; the end portion of the inner protection plate 3 is connected with the crown beam embedded part by high-strength bolts; The inner support system is arranged on both sides of the steel pipe pile 200 to increase the overall supporting stability and provide a force point for the hydraulic jack 4 support; The hydraulic jack 4 is arranged between the outer support system of the crown beam excavation area and the inner support system of the crown beam formwork, the hydraulic jack 4 is uniformly lifted by the piston rod, the axial load is applied step by step, the pressure value is fed back in real time by the digital instrument, and it is ensured that the pressure reaches the set value; S3, crown beam main body construction Steel reinforcement engineering The main reinforcement is connected by a straight thread sleeve, and the waist reinforcement is fixed by welding; Formwork engineering The formwork is assembled by using a shaped steel formwork, a closed-cell foam sealing strip is pasted at the formwork joint, φ16 opposite-pull bolts are used for formwork reinforcement, and the verticality is detected after the formwork is installed; Concrete pouring The concrete is poured by using an automobile pump in layers, and a φ50 insertion type vibrating rod is used for vibration; immediately after pouring, geotextile is covered for moisture curing.

[0039] The pressure application of the hydraulic jack 4 adopts step loading, including the following stages: Initial pre-tightening: 30% of the design axial force is applied, and the pressure is stabilized for 10 minutes; Second load: increased to 60% of the design axial force, stable for 15 minutes; Third load: increased to 90% of the design axial force, stable for 20 minutes; Final load: reach 100% design axial force, stable for 30 minutes.

[0040] After the crown beam concrete strength meets the design requirements, first release the pressure of hydraulic jack 4, remove the hydraulic jack 4, remove the internal support system outside the crown beam formwork, remove the support beam 2 support on the upper part of the external support system, and finally remove the outermost external support system.

[0041] Before the preset steel strand of the crown beam is tensioned, the tensioning slope is ground in advance, a 180x310x20 steel pad is placed, and then the anchor is installed for tensioning.

[0042] φ219x10mm external support steel pipe diagonal bracing is arranged outside the crown beam, the external support steel pipe diagonal bracing penetrates the silt layer into the stable bearing layer at an angle of 55°±5°, the horizontal spacing is 2.5m, the upper end is connected by a flange plate, and the lower end is provided with an enlarged bearing plate to reduce the foundation stress.

[0043] The support beam 2 adopts H400x400x13x21 type, is arranged at an interval of 3.0m, and provides internal prestress; adjustable supports are arranged at the ends of the support beam 2, and the support beam 2 is fixed with the crown beam formwork support.

[0044] During the construction preparation stage, first, the measurement and line laying are performed: the construction control network is established, and the accuracy is controlled within ±5mm; and the material preparation: the steel is rechecked upon entering the site, and the concrete mix ratio is designed.

[0045] During the construction of the crown beam support, the coffer pile construction is completed, after the steel pipe pile 200 pile body strength or age reaches the design requirements, the crown beam and the crown beam support earthwork excavation limit is determined by the measurement and line laying, the excavator is used to excavate the crown beam earthwork to the beam bottom, and the earthwork is removed to the design bottom elevation of the crown beam. During the earthwork excavation process, the disturbance to the steel pipe pile and the steel sheet pile is avoided as much as possible. After the crown beam foundation trench earthwork excavation is completed, the concrete cushion is constructed, the 30cm thick C20 plain concrete cushion is poured, the surface flatness is controlled within ±10mm, and the construction meets the minimum requirement that the pile body extends into the crown beam. The outer support system is arranged on the upper part of the concrete cushion, and the support beam 2 is additionally arranged on the upper part to avoid the silt soil flowing into the crown beam and to strengthen the stability of the soil body. The crown beam formwork internal support system is arranged in the crown beam construction range on the top of the steel pipe pile and the steel sheet pile to provide conditions for the construction of the crown beam. After the support is completed, the hydraulic jack is used between the internal support system and the external support system to pressurize and fix, so that the system is firm and stable.

[0046] During the construction of the crown beam, the crown beam reinforcement is lashed and installed with attention to the lap joint requirements, with a lap joint of 50% and a lap joint length of 49d, and the pile body is inside the crown beam reinforcement. The crown beam is constructed in sections, and connecting reinforcement is reserved at the joint of each section. The main reinforcement is C25, and the stirrup is A8@200. After the completion of the crown beam formwork installation, the anchor cable position is located before the concrete pouring, and A75 hard PVC pipes are pre-buried for anchor cable tensioning. After the completion of the construction, the jack pressure detection and support system stability inspection are carried out daily.

[0047] Example 2 On the basis of Example 1, the support system formed by the external support system, the internal support system and the hydraulic jack works cooperatively, and the support method comprises the following steps: S1, site survey and measurement lofting Before construction, the engineering geological re-investigation is carried out, and the thickness of silt layer, physical and mechanical indexes and groundwater conditions are mainly ascertained. The total station is used for measurement lofting, the construction control network is established, the plane control point interval is not greater than 50m, and the elevation control point interval is not greater than 30m. All control points are subjected to closure measurement, the plane position error is controlled within ±5mm, and the elevation error is controlled within ±3mm.

[0048] Construction of cushion layer A 30cm thick C20 plain concrete cushion layer is poured and vibrated compacted by using a flat plate vibrator. The flatness of the cushion layer surface is checked by using a 2m straightedge, and the deviation is not greater than 10mm. The curing time of the cushion layer is not less than 3 days, and the strength reaches 5MPa before the next process is carried out.

[0049] S2, support system installation 2.1 External support system construction Measurement positioning: the plane position and elevation of each support point are marked out by using the total station for accurate positioning, and the error is controlled within ±5mm.

[0050] Guide frame installation: an adjustable guide frame is set to ensure the verticality of the steel pipe setting. The rigidity of the guide frame needs to meet the construction requirements, and the deformation is not greater than 2mm.

[0051] Steel pipe sinking: the hydraulic vibration hammer is used for pile sinking, and the low gear (frequency 15-20Hz) is slowly sunk in the initial stage, and is increased to 25-30Hz after entering the bearing layer. The verticality is monitored in real time during the pile sinking process, and the deviation is more than 1 / 200, which needs to be corrected in time.

[0052] Pile end treatment: after the pile is sunk in place, C25 micro-expanding concrete is poured at the pile end to seal the bottom, and the thickness is not less than 50cm.

[0053] 2.2 Internal support system installation Support beam processing: H-shaped steel support beam is prefabricated in the factory, and the end is welded with a 20mm thick reinforcing rib plate. All welds need to be ultrasonically tested, and the quality grade shall not be less than B level.

[0054] On-site assembly: First install support beam 2, using two truck cranes to lift simultaneously. Immediately after the support beam 2 is in place, install the temporary fixing device.

[0055] Node connection: The end of the inner protective plate 3 is connected to the crown beam embedded part using high-strength bolts. The bolt tightening is done in three stages, and the final torque reaches ±5% of the design value.

[0056] 2.3 Hydraulic jack installation Jack arrangement: Two 200t hydraulic jacks 4 are arranged corresponding to each support beam, with a centerline deviation of no more than 3mm from the support axis.

[0057] Oil line connection: High-pressure hydraulic hose is used for connection, with a working pressure set at 31.5MPa. After oil line installation, 1.5 times working pressure test is required, with no leakage for 10 minutes.

[0058] Sensor installation: Displacement sensors are fixed on special brackets, with the measurement direction consistent with the support axis. Pressure sensors are installed in the oil line system, and zero-point calibration is required before installation.

[0059] S3, Crown beam main body construction 3.1 Steel reinforcement engineering Main reinforcement uses straight thread sleeve connection, with joint grade I, and joint rate of no more than 50% for the same section. The waist reinforcement is fixed by welding, with a weld length of no less than 10d. The installation position deviation of the embedded part is no more than 5mm, and secondary review is required after fixation.

[0060] 3.2 Formwork engineering Use shaped steel formwork assembly, and paste 10mm thick closed-cell foam sealing strip at the formwork joint. Formwork reinforcement uses φ16 tension bolts with a spacing of 600mm x 600mm. Verticality detection is required after formwork installation, with a deviation controlled within 1 / 500.

[0061] 3.3 Concrete pouring Use truck pump to pour layer by layer, with each layer thickness controlled within 50cm. Use φ50 insertion type vibrating rod with a spacing of no more than 40cm, and each point vibrating time of 20-30s. Immediately cover geotextile after pouring to maintain moisture, with a curing time of no less than 14 days.

[0062] 3.4 Hydraulic jack pressure application uses step loading Initial pre-tightening: Apply 30% of the design axial force, and stabilize for 10 minutes; Secondary loading: increased to 60% of the design axial force, stabilized for 15 minutes; Third loading: increased to 90% of the design axial force, stabilized for 20 minutes; Final loading: reached 100% of the design axial force, stabilized for 30 minutes.

[0063] 3.5 Synchronous control The PLC control system is used to realize synchronous jacking of multiple hydraulic jacks, and the synchronous error is controlled within ±2mm. The support axial force is monitored in real time during loading, and the axial force deviation between each support is not more than ±5%.

[0064] 3.6 Displacement monitoring The crown beam displacement is recorded every 5 minutes during loading, and the displacement increment caused by single loading is not more than 1mm. If abnormal displacement is found, the loading is immediately stopped and the reason is analyzed.

[0065] The three-dimensional collaborative support system of the outer support system, the inner support system and the hydraulic jack controls the crown beam horizontal displacement within a safe range, and reduces the deformation amount by more than 40% compared with the traditional method; The hydraulic jack can offset the deformation of silt rheology, and control the long-term creep rate within the standard; The millimeter-level (±2mm) displacement precision control is realized through the PLC control system, which meets the deformation control requirements of the special foundation pit.

[0066] Optimizing the support arrangement reduces the steel consumption by 25-30%, and saves 0.8 tons of steel per meter for a 10m deep foundation pit; The parallel construction of vacuum preloading and support shortens the construction period by 15-20 days, and improves the comprehensive construction efficiency by 40%.

[0067] Two hydraulic jacks are arranged on the same longitudinal section, and the double-jack redundant design ensures that 50% of the design support force is maintained when a single machine fails; The emergency power supply system ensures 8 hours of continuous support capacity under power failure.

[0068] The scheme is successfully applied to silt stratum with water content of 60-80% and sensitivity of 4-8; the support recovery rate is more than 95%, the hydraulic system can be reused more than 50 times; it can be matched with an intelligent monitoring platform and a BIM system to seamlessly dock, and support digital construction.

[0069] The above only describes the preferred embodiments of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A support system for construction of a coastal paralic sludge ground crown beam, characterized in that, It comprises an outer support system, an inner support system and hydraulic jacks (4); The outer support system comprises two symmetrically arranged outer protection plates (1) on both sides of the crown beam (100); The inner support system comprises several evenly distributed support beams (2) arranged between the top of the two outer protection plates (1) and two symmetrically arranged inner protection plates (3) on both sides of the crown beam (100); The several evenly distributed hydraulic jacks (4) are arranged between the outer protection plate (1) and the inner protection plate (3); The outer protection plate (1) comprises an outer protection vertical plate (101), an outer protection inclined plate (102) and an outer protection horizontal plate (103) connected with each other; The inner protection plate (3) is arranged in an L shape and comprises an inner protection vertical plate (301) and an inner protection horizontal plate (302); The support beam (2) adopts H-shaped steel.

2. The support system for coastal muds geocrown construction according to claim 1, characterized in that, The inner walls of the two inner protection plates (3) are matched with the crown beam (100).

3. The support system for coastal muds geocrown construction according to claim 2, characterized in that, The two outer protection horizontal plates (103) and the two inner protection plates (3) are located on both sides of the top of the steel pipe pile (200).

4. The support system for coastal muds geocrown construction according to claim 3, characterized in that, The hydraulic jacks (4) are arranged between the outer protection vertical plate (101) and the inner protection vertical plate (301) and between the outer protection inclined plate (102) and the inner protection vertical plate (301), that is, two hydraulic jacks (4) are arranged on the same longitudinal section. The fixed end of the hydraulic jack (4) is fixedly connected with the outer protection vertical plate (101) and the outer protection inclined plate (102), and the telescopic end of the hydraulic jack (4) is fixedly connected with the outer wall of the inner protection vertical plate (301).

5. The support system for coastal muds geocrown construction according to claim 4, characterized in that, The outer protection inclined plate (102) is arranged in an inclined manner. The support beam (2) is horizontally supported between the two outer protection vertical plates (101). The support beam (2) adopts H400x400x13x21 type and is arranged at an interval of 3.0 m to provide internal prestress. The hydraulic jack (4) adopts 200t level to realize dynamic force system balance.

6. The support system for coastal muds geocrown construction according to claim 5, characterized in that, An outer support steel pipe inclined support is arranged on the inner side of the outer wall of the end of the outer protection plate (1), the outer support steel pipe inclined support adopts φ219x10mm steel pipe, penetrates the sludge layer into the stable bearing layer at an inclination of 55°±5°, is arranged at an interval of 2.5 m to form external anti-sliding constraint, the upper end is connected by a flange plate, and the lower end is provided with an enlarged bearing plate to reduce foundation stress.

7. A method of shoring a shore system for construction of a coastal paralic sludge crown beam according to any one of claims 1-6, characterized in that It comprises the following steps: S1, site investigation and measurement lofting Before construction, the engineering geological re-investigation is carried out, the thickness of the sludge layer, the physical and mechanical indexes and the underground water conditions are ascertained, the total station instrument is used for measurement lofting, and the construction control network is established; The concrete cushion is poured and vibrated to be compacted by using a flat plate vibrator; S2, support system installation The crown beam (100) construction area is excavated to below the crown beam construction elevation after the steel pipe pile (200) construction is completed; The outer support system of the crown beam construction support system is arranged in the crown beam (100) excavation area, and the support beam (2) is supported on the upper part; the support beam (2) is hoisted by two truck cranes; the H-shaped steel support beam is prefabricated in the factory, and the end is welded with a reinforcing rib plate; the end of the inner protection plate (3) is connected with the crown beam embedded part by high-strength bolts; The inner support system is arranged on both sides of the steel pipe pile (200) to provide a force point for the hydraulic jack (4) support; The hydraulic jack (4) is arranged between the outer support system and the inner support system of the corbel formwork in the corbel excavation area, and the hydraulic jack (4) applies axial load step by step; S3, corbel main body construction Steel reinforcement engineering The straight thread sleeve is used for connecting the main reinforcement, and the waist reinforcement is fixed with the main reinforcement by welding; Formwork engineering The shaped steel formwork is assembled, the closed-cell foam sealing strip is pasted at the formwork joint, the formwork is reinforced by the φ16 tension bolt, and the verticality of the formwork after installation is detected; Concrete pouring The automobile pump is used for layered pouring, the φ50 insertion type vibrating rod is used for vibrating, and the geotextile is covered immediately after pouring to maintain moisture.

8. The supporting method of the supporting system for coastal facies sludge ground crown beam construction according to claim 7, characterized by The pressure of the hydraulic jack (4) is applied by grading loading, Including the following stages: Initial pre-tightening: 30% of the design axial force is applied, and the pressure is stabilized for 10 minutes; Second loading: increased to 60% of the design axial force, stabilized for 15 minutes; Third loading: increased to 90% of the design axial force, stabilized for 20 minutes; Final loading: 100% of the design axial force is reached, and the pressure is stabilized for 30 minutes.

9. The support method of the support system for coastal facies sludge ground crown beam construction according to claim 7, characterized by, After the corbel concrete strength reaches the design requirement, the pressure of the hydraulic jack (4) is released first, the hydraulic jack (4) is removed, the inner support system outside the corbel is removed, the support beam (2) support on the upper part of the outer support system is removed, and finally the outermost outer support system is removed; Before the preset steel strand of the corbel is tensioned and anchored, the tensioning slope is ground in advance, the 180×310×20 steel pad is placed, and then the anchor device is installed for tensioning.

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