Tanking construction method for pipe-roofing-structure-originating and ultra-thick-rock-stratum diaphragm wall in coastal area

Abstract

The invention relates to the technical field of pipe roof structure construction methods, and discloses a coastal area pipe roof structure originating and ultra-thick rock stratum diaphragm wall grooving construction method which comprises the steps that S1, preparation is conducted before construction; s2, guide wall construction; s3, slurry preparation; s4, first-stage groove construction; s5, ultrasonic perpendicularity detection; s6, bottom cleaning and slurry changing; s7, the reinforcement cage is hoisted, concrete is poured, and the supporting mechanism is pulled out before initial setting of the concrete; and S8, second-stage groove construction and the like. The conditions of collapse, necking and the like can be effectively avoided, the construction period is short, the construction reliability is high, and the water stopping effect is good; the problems that according to an existing grooving method, the layer grooving position is not accurate, and the grooving perpendicularity is difficult to guarantee are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe-roof structure construction methods, and in particular relates to a method for constructing a pipe-roof structure in a coastal area and forming a trench for a ground-connected wall in an ultra-thick rock formation. Background Art

[0002] With the development of economy, the land development in coastal areas and reclamation areas is increasing, which poses a great challenge to the safe construction of foundation pit projects. Underground continuous wall is widely used as a common form of retaining structure due to its advantages of high strength, high rigidity, good anti-seepage performance and integrity.

[0003] Due to the complex geological conditions in coastal areas, the trenching construction of ultra-deep underground continuous walls is difficult. Trench wall collapse and necking are prone to occur in silt layers and sand layers. During traditional construction methods, three-axis cement mixing piles are installed on both sides of the ground-connected wall to improve the soil quality. However, due to the influence of various factors, some trench wall guard piles will be tilted, seriously encroaching on the construction axis of the ground-connected wall, making it very easy for the hydraulic trenching machine to deviate during the trenching process. At the same time, when trenching ultra-deep underground continuous walls, there are also problems such as the decline in the efficiency of double-wheel milling machines in thick rock formations, the time-consuming and labor-intensive secondary removal of sediment, and the impact of incomplete sediment removal on the water-stopping effect of the ground-connected wall. At the same time, the verticality of the trenching of deeper ground-connected walls is difficult to guarantee.

[0004] Therefore, it is necessary to propose a method for constructing trenches for pipe-roof structures in coastal areas and ground-connected walls in ultra-thick rock formations to solve the problems of the above-mentioned prior art. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a method for constructing trenches for ground-connected walls in ultra-thick rock strata starting from a pipe curtain structure in coastal areas, which has the advantages of effectively avoiding landslides, necking, etc., short construction period, strong construction reliability and good water-stopping effect; and solves the problems of inaccurate trenching positions and difficulty in ensuring trenching verticality in existing trenching methods.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose of facilitating the placement of sample tubes of different sizes, the present invention provides the following technical solutions: A method for constructing a trench for a pipe-roof structure in a coastal area and a ground-connected wall in an ultra-thick rock formation, comprising the steps of: S1: Preparation before construction Find out the soil conditions at different depths within the trenching range, select trenching equipment for different soil layers, and determine the lowest construction platform elevation for site leveling; S2: Guide wall construction According to the designed underground continuous wall axis position, lay out the earthwork, lay the cushion layer after excavation, and then tie the guide wall side wall and wing plate steel bars, set up the formwork, and pour concrete; backfill the guide wall in time after removing the formwork. When the concrete strength of the guide wall reaches 75% of the designed strength, carry out trench construction, and divide the trench section into the first-stage trench and the second-stage trench; S3: Mud preparation When preparing mud, determine the mud formula based on the soil layer that is most likely to collapse; S4: Phase I trough construction; S5: Ultrasonic verticality detection; S6: Clean the bottom and change the slurry Use a combination of sedimentation and replacement methods to clean the bottom and replace the slurry; S7. Hoist the steel cage and pour concrete, and pull out the support mechanism before the concrete begins to set; S8: Phase II trench construction.

[0008] Preferably, the mud described in step S3 is made of bentonite as the main material, anhydrous sodium carbonate as the dispersant, carboxymethyl cellulose as the fluid loss reducer, barite powder as the weighting agent, and pulp fiber as the plugging agent. The density of the newly prepared mud is 1.05-1.15 g / cm 3 , viscosity 18~22, sand content ≤4%.

[0009] Preferably, the first phase trench construction process described in step S4 includes: S4.1: Divide each slot section into three sections along the length direction, namely the first slot section, the second slot section and the third slot section; S4.2: excavate the first and third trench sections to the soil-rock interface; then excavate the second trench section so that the second trench section is at least 5m higher than the first and third trench sections; S4.3: Set up support structures in the silt layer, sand layer, etc. of the excavated trench section; S4.4: Use a double-wheel milling machine to mill the first and third slot sections to the designed depth; finally, mill the second slot section to the designed depth.

[0010] Preferably, during ultrasonic testing in step S5, the verticality of the groove wall is observed through the correction plates on the groove forming machine and the double-wheel groove milling machine to see whether it meets the requirements, and ultrasonic testing is performed through an ultrasonic detector to detect whether the verticality meets the requirements; if so, the groove forming is continued, if not, the groove repair construction is continuously carried out according to the ultrasonic image and the correction prompt information on the correction plate.

[0011] Preferably, during ultrasonic testing, testing is performed every 5 m, and testing is performed at the soil stratification. When the verticality does not meet the requirements, timely correction is performed to achieve dynamic correction. During ultrasonic verticality testing, 3 positions are selected for testing in the two longitudinal sections of the trough section, and 1 position is selected for testing in the transverse section.

[0012] Preferably, when using the sedimentation method to clean the bottom, it is necessary to start one hour after the trenching is completed, and use the hydraulic grab bucket of the trenching operation to directly remove the sediment at the bottom of the trench.

[0013] Preferably, when using the replacement method for slurry replacement, a pump suction reverse circulation slurry replacement is adopted. The slurry replacement pump is hoisted by a crane to a place 1 meter away from the bottom of the trough. The slurry replacement pump is started to suck up the sediment at the bottom of the trough, and at the same time, slurry is added at the trough mouth. During the whole process of bottom cleaning and slurry replacement, the balance between the amount of slurry suction and the amount of slurry addition is controlled, and the slurry is not allowed to overflow from the trough or the slurry surface is not allowed to fall below the groundwater level by more than 1m.

[0014] Preferably, the second-phase trench construction process described in step S8 includes milling the second-phase trench by milling, the second-phase trench is divided into a trench section and formed at one time, the second-phase trench milling connection with the first-phase trench milling connection should be more than 30 cm, and the second-phase trench construction should be carried out after the concrete strength of the first-phase trench reaches 75%.

[0015] Preferably, the support mechanism includes a wheelbase adjustment assembly, a threaded sleeve, a connecting rod, an auxiliary positioning foot and a support assembly. The wheelbase adjustment assembly is arranged in a connecting pipe, and includes a first bevel gear, a second bevel gear and a first damping adjustment disk. The first bevel gear is installed at the end of the threaded sleeve and meshes with the second bevel gear. The second bevel gear is arranged at the end of the first damping adjustment disk coupling, and the threaded sleeve is rotatably connected to the connecting pipe through a bearing.

[0016] Preferably, the support assembly includes a supporting foot, a first connecting shaft, a second connecting shaft, an adjustment unit, a fixed connecting piece and a sliding connecting piece. The supporting foot is arranged at the end of the first connecting shaft, contacts with the inner wall of the supporting steel plate, and is hingedly connected to one end of the first connecting shaft. The other end of the first connecting shaft is hingedly connected to the sliding connecting piece. The sliding connecting piece is movably sleeved on the threaded sleeve through the adjustment unit, and is a movable end. The fixed connecting piece is fixedly arranged on the connecting rod through a fixing pin, and is a fixed end, and is hingedly connected to one end of the second connecting shaft. The other end of the second connecting shaft is hingedly connected to a hinge point arranged in the middle of the first connecting shaft to form a claw-like structure.

[0017] Preferably, the adjustment unit is arranged on the threaded sleeve, and includes a second damping adjustment disk, a driving member and a third spur gear. The driving member is movably arranged in the cavity of the threaded sleeve, and the third spur gear is arranged in the inner cavity of the threaded sleeve through the coupling rotation of the second damping adjustment disk, and is engaged with a rack arranged at the tail of the driving member.

[0018] (III) Beneficial effects

[0019] Compared with the prior art, the present invention provides a method for constructing trenches for pipe-roof structures in coastal areas and ground-connected walls in ultra-thick rock formations, which has the following beneficial effects: 1. This method prefabricates the support mechanism in advance in the factory according to the geological exploration results. During construction, the support mechanism is set in the poor strata such as silt layer and sand layer, which protects the stability of the trench wall, prevents landslides and necking in the strata with poor soil properties, and avoids the construction difficulties caused by the construction of retaining wall piles on both sides of the ground-connected wall; 2. This method uses an air floater to deliver compressed air into the slot during rock construction, so that the rock blocks crushed by the slot milling machine are suspended in the wall protection mud, avoiding the repeated crushing of the rock blocks accumulated at the bottom of the slot by the double-wheel slot milling machine during construction, which causes huge waste, improves the construction efficiency, saves construction time and reduces costs; 3. This method adopts a slag removal process that combines sedimentation method and replacement method to ensure the bottom slag removal effect and further ensure the water-stopping effect of the bottom of the groove. At the same time, the connection between the first-phase groove and the second-phase groove adopts the milling method to ensure the water-stopping effect of the connection node, effectively ensuring the overall water-stopping effect of the ground-connected wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a process flow chart of the invention for constructing trenches for the pipe-roof structure in coastal areas and for forming ground-connected walls in ultra-thick rock formations; Figure 2 This is a schematic diagram of the distribution of slot sections and lead holes of the present invention; Figure 3 This is an installation effect diagram of the support mechanism of the present invention; Figure 4 It is a structural schematic diagram of the support mechanism of the present invention; Figure 5 It is a structural schematic diagram of the middle adjustment mechanism of the present invention; Figure 6 is a cross-sectional view of the middle adjustment mechanism of the present invention; Figure 7 It is a partial enlarged view of the middle adjustment mechanism A of the present invention.

[0021] Among them, 1. the first phase trough; 2. the second phase trough; 3. the first trough section; 4. the second trough section; 5. the third trough section; 6. the soft soil layer guide hole; 7. the rock layer guide hole; 8. the supporting mechanism; 81. the wheelbase adjustment assembly, 811. the connecting pipe, 812. the first bevel gear, 813. the bearing, 814. the second bevel gear, 815. the first damping adjustment disk, 82. the threaded sleeve, 821. the adjustment groove, 83. the connecting rod, 831. the return spring, 84. the auxiliary positioning foot, 85. the supporting foot, 86. the first connecting shaft, 87. the second connecting shaft, 88. the adjusting unit, 881. the second damping adjustment disk, 882. the driving member, 883. the third spur gear, 884. the rack, 885. the push plate protrusion, 89. the fixed connecting member, 891. the fixing pin, 80. the sliding connecting member; 801. the supporting steel plate; 802. the supporting nail; 9. the guide wall. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1: Please refer to Figure 1-3 , the present invention provides a technical solution: A method for constructing a trench for a pipe-roof structure in a coastal area and a super-thick rock layer ground-connected wall, which is applied to geological layers of soft soil and super-thick rock layers, comprises the following steps: S1: Preparation before construction Find out the soil conditions at different depths within the trenching range, select trenching equipment for different soil layers, determine the lowest construction platform elevation to level the site, connect electricity and wires, connect water and electricity pipelines within the construction site, arrange the construction site, and prepare machinery and equipment, personnel, and materials; S2: Guide wall construction According to the designed underground continuous wall axis position, lay out the earthwork and excavate it. After excavation, lay the cushion layer at the bottom of the guide wall, then tie the guide wall side wall and wing plate steel bars, set up the formwork, and pour concrete. After the guide wall is demolished, backfill it in time. When the concrete strength of the guide wall reaches 75% of the designed strength, carry out the underground continuous wall trench construction, and divide the underground continuous wall trench section into the first-stage trench 1 and the second-stage trench 2 (using the skipping method for construction); Among them, the use of the skipping method for construction can save construction time and ensure safety. The skipping method requires us to have multiple slot sections; during the skipping construction, the slot sections on both sides have been completed before the construction of the middle slot section, that is, the first-phase slots 1 on both sides have been completed before the construction of the second-phase slot 2, that is, the concrete has been poured. At the same time, in order to ensure the integrity of the ground-connected wall, the present invention uses the milling method to connect different slot sections; the working distance of the slot milling machine fundamentally restricts the length of the second-phase slot to not exceed the maximum distance of the slot milling machine at one time. Therefore, the second-phase slot 2 is different from the first-phase slot 1 (if the first-phase slot 1 is required to be the same as the second-phase slot 2, the length of the first-phase slot 1 will not exceed the length of one milling, which will make the construction safer, but at the same time, it may not be ideal in terms of economy and saving construction time); the slot section division is related to multiple factors, such as the reasonable distance of the construction machinery for one construction, the structural form and construction process of the ground-connected wall, the surrounding buildings and underground pipelines, the construction level of the construction team, the geological conditions of the construction site and other factors will affect the slot section division; S3: Mud preparation When preparing mud, the mud formula is determined based on the soil layer that is most prone to collapse, which is generally the silt layer or sand layer in coastal areas; during specific construction, the mud density and height are adjusted according to the actual stratum conditions, groundwater level conditions, surface overload conditions, etc. S4: Construction of Phase I Trough 1 S4.1: Divide each slot section into three sections along the length direction, namely, a first slot section 3, a second slot section 4 and a third slot section 5; S4.2: excavate the first trench section 3 and the third trench section 5 to the soil-rock interface; then excavate the second trench section 4, so that the second trench section 4 is at least 5m higher than the first trench section 3 and the third trench section 5; Among them, the purpose of segmented excavation is to increase the length of the first-stage trench as much as possible under the premise of ensuring safety, avoid multiple milling, and save costs and construction period; the second trench section 4 is at least 5m higher in order to make the second trench section 4 a constraint to provide resistance for the construction of the first trench section 3 and the third trench section 5. At the same time, the second trench section 4 is slightly higher, which is equivalent to increasing the influence of the trench section corner effect and reducing the deformation of the trench wall; S4.3: A support mechanism 8 is provided in the silt layer, sand layer, etc. of the excavated trench section; If the rock and soil layer below the lowest weak layer is strong, the support mechanism 8 can be placed directly on the layer to support it. Figure 3 As shown; S4.4: Use a double-wheel slot milling machine to mill the first slot section 3 and the third slot section 5 to the designed depth; finally, mill the second slot section 4 to the designed depth; On it, the skipping construction process as described above is adopted to ensure the safety of the structure; S5: Ultrasonic verticality detection During the grooving process, the guide plates on the grooving machine and the double-wheel milling machine are used to observe whether the verticality of the grooving wall meets the requirements, and an ultrasonic detector is used to perform ultrasonic testing to check whether the verticality meets the requirements. If yes, the grooving continues; if not, the grooving is continuously repaired according to the ultrasonic image and the guide information on the guide plate. S6: Clean the bottom and change the slurry Use a combination of sedimentation and replacement methods to clean the bottom and replace the slurry; The sedimentation method should be used to clean the bottom of the trench one hour after the trench is formed. The hydraulic grab bucket used for trenching operations should be used to directly remove the sediment from the bottom of the trench. The replacement method uses pump suction reverse circulation slurry replacement. The slurry replacement pump is hoisted 1 meter away from the bottom of the tank by a crane, and the slurry replacement pump is started to suck up the sediment at the bottom of the tank, and the slurry is replenished at the slot mouth at the same time. During the whole process of bottom cleaning and slurry replacement, the balance between the slurry suction volume and the slurry replenishment volume is controlled well, and the slurry cannot overflow from the tank or the slurry surface cannot fall below the groundwater level by more than 1 meter. S7. Hoist the steel cage and pour concrete, and pull out the support mechanism before the concrete begins to set; S8: Construction of Phase II Trough 2 The second-stage slot 2 is milled by milling method. The second-stage slot 2 is divided into one slot section and the milling connection between the second-stage slot 2 and the first-stage slot should be more than 30cm. The second-stage slot 2 should be constructed when the concrete strength of the first-stage slot 1 reaches 75%; the size of the first-stage slot 1 and the second-stage slot 2 should be determined comprehensively according to the size of the double-wheel slot milling machine, geological conditions, and the size of the ground-connected wall; The second phase trench 2 is connected to the first phase trench 1 in the horizontal direction. This connection is like a bite pile, which is mainly to ensure the integrity. The second phase trench is constructed after the first phase trench, and the concrete strength of the first phase trench reaches a certain value. If milling is not performed, the safety of the connection cannot be guaranteed at the joint, and water stopping failure or even wall damage may occur.

[0024] As a preferred implementation scheme, bentonite is selected as the main material when preparing the mud, anhydrous sodium carbonate is used as a dispersant, carboxymethyl cellulose (CMC) is used as a filtration reducer, barite powder is used as a weighting agent, and pulp fiber is used as a plugging agent. The density of the newly prepared mud is 1.05~1.15g / cm 3 , viscosity 18~22, sand content ≤4%. During the construction process, various performance indicators of the mud are measured, specifically, the mud density is measured by a mud specific gravity meter, the mud viscosity is measured by a Soderbergh funnel viscometer, the sand content is measured by a 200-mesh sieve, the colloid rate is measured by a measuring cylinder, and the pH value is measured by pH test paper.

[0025] As a preferred implementation scheme, the grooving process of this scheme adopts a grooving method that combines "grasping, drilling, punching, hammering, and milling". For the upper soft soil area, a construction method combining a grooving machine and a rotary drilling drill is used when grooving. First, a rotary drilling drill is used to set guide holes around both sides of the grooving section, and then a grooving machine is used for grooving; for deep rock areas, a construction method combining an air flotation machine, an impact drill, a pneumatic down-the-hole hammer, and a double-wheel milling machine is used when grooving. In fully weathered and strongly weathered rock formations, an impact drill is first used to drill guide holes in the grooving section in a plum blossom shape, and then a double-wheel milling machine is used for milling grooves. In moderately weathered and slightly weathered rock formations, on the basis of drilling guide holes with an impact drill, a pneumatic down-the-hole hammer is used to hammer the rock mass to break it, and then a double-wheel milling machine is used for milling grooves. In addition, during rock formation construction, an air flotation machine is turned on to inject compressed air into the grooving to suspend the broken rock blocks and avoid secondary rock breaking by the milling machine; when encountering large isolated rocks in the fill layer, an impact drill combined with a grooving machine is used.

[0026] As a preferred implementation scheme, ultrasonic verticality testing should be carried out every 5m and at the soil stratification. When the verticality does not meet the requirements, timely correction should be made to achieve dynamic correction. During ultrasonic verticality testing, three positions should be selected for testing in the two longitudinal sections of the trough section, and one position should be selected for testing in the transverse section.

[0027] As a preferred embodiment, Figure 3 As shown, when excavating the upper soft soil area of ​​the first-phase trench 1, the trench edges should be expanded outward by 10 cm to place the support mechanism 8; the height of the support mechanism 8 should be 50 cm higher than the silt layer and other unfavorable strata, and the size is determined by the geological exploration of the trench area and the size of the trench body.

[0028] As a preferred embodiment, Figure 2 As shown, a soft soil layer lead hole 6 is provided on the first trench section 3, and a rock layer lead hole 7 is provided on the second trench section 4. The soft soil layer lead hole 6 and the rock layer lead hole 7 can play a guiding and positioning role to ensure the position accuracy and verticality of the ground-connected wall; and the soft soil layer lead hole 6 and the rock layer lead hole 7 can also play a role in seismic reduction and isolation. The air surface generated by the soft soil layer lead hole 6 and the rock layer lead hole 7 will reduce the impact of mechanical construction on the trench wall, and play a role similar to that of the peripheral holes in tunnel blasting.

[0029] Example 2: Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, the support mechanism 8 includes a wheelbase adjustment component 81, a threaded sleeve 82, a connecting rod 83, an auxiliary positioning foot 84 and a support component. The wheelbase adjustment component 81 is arranged in a connecting pipe 811, and includes a first bevel gear 812, a second bevel gear 814 and a first damping adjustment disk 815. The first bevel gear 812 is installed at the end of the threaded sleeve 82 and meshes with the second bevel gear 814. The second bevel gear 814 is arranged at the end of the first damping adjustment disk 815, and the threaded sleeve 82 is rotatably connected to the connecting pipe 811 through a bearing 813. Specifically, when in use, the first damping adjustment disk 815 with damping performance is manually adjusted to rotate, and the meshing force between the second bevel gear 814 and the first bevel gear 812 drives the two threaded sleeves 82 to rotate, and an internal thread is provided in the threaded sleeve 82 to cooperate with the external thread of the connecting rod 83, that is, the threaded sleeve 82 is threadedly connected with the connecting rod 83; the relative threaded depth between the threaded sleeve 82 and the connecting rod 83 is adjusted by rotating the threaded sleeve 82, so as to adjust the overall supporting length of the supporting mechanism 8, so that it is convenient for transportation and suitable for supporting two supporting steel plates of different widths, and the tail end of the auxiliary positioning foot 84 is provided with a threaded rod threadedly connected with the connecting rod 83, so as to facilitate the initial positioning of the supporting mechanism 8 when in use.

[0030] As a preferred embodiment, Figure 4 , Figure 5 , Figure 6 and Figure 7As shown, the support assembly includes four support legs 85, a first connecting shaft 86, a second connecting shaft 87, an adjustment unit 88, a fixed connection member 89 and a sliding connection member 80. The support leg 85 is arranged at the end of the first connecting shaft 86, contacts the inner wall of the supporting steel plate 801, and is hingedly connected to one end of the first connecting shaft 86. The other end of the first connecting shaft 86 is hingedly connected to the sliding connection member 80. The sliding connection member 80 is movably sleeved on the threaded sleeve 82 through the adjustment unit 88, and is a movable end. The fixed connection member 89 is fixedly arranged on the connecting rod 83 through a fixing pin 891, and is a fixed end, and is hingedly connected to one end of the second connecting shaft 87. The other end of the second connecting shaft 87 is hingedly connected to a hinge point arranged in the middle of the first connecting shaft 86 to form a claw-like structure. Specifically, when in use, when the sliding connector 80 moves relative to the fixed connector 89, the first connecting shaft 86 opens outward to expand its supporting area. In order to facilitate the sliding connector 80 to be reset and folded after the time is up, a reset spring 831 is also provided on the connecting rod 83 between the fixed connector 89 and the sliding connector 80.

[0031] As a preferred embodiment, Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, the adjustment unit 88 is arranged on the threaded sleeve 82, and includes a second damping adjustment disk 881, a driving member 882 and a third spur gear 883. The driving member 882 is movably arranged in the cavity of the threaded sleeve 82. The third spur gear 883 is arranged in the inner cavity of the threaded sleeve 82 through the shaft connection rotation of the second damping adjustment disk 881, and is meshed with a rack 884 arranged at the tail of the driving member 882. Specifically, when in use, by adjusting the second damping adjustment disk 881 to rotate, the meshing force between the third spur gear 883 and the rack 884 is used to drive the driving member 882 to move in the inner cavity of the threaded sleeve 82, and push plate protrusions 885 are symmetrically arranged on the driving member 882. The push plate protrusions 885 are used in conjunction with the adjustment groove 821 arranged on the threaded sleeve 82, that is, the push plate protrusion 885 extends out of the adjustment groove 821 and presses against the inner side of the threaded sleeve 82. The movement of the push plate protrusion 885 pushes the sliding connection member 80 to move, so that the first connecting shaft 86 is opened outward to expand its support area and support the side walls of the guide walls on both sides of the slot.

[0032] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for constructing trenches for pipe-roof structures in coastal areas and ground-connected walls in ultra-thick rock formations, characterized in that: Included steps S1: Preparation before construction Find out the soil conditions at different depths within the trenching range, select trenching equipment for different soil layers, and determine the lowest construction platform elevation for site leveling; S2: Guide wall construction According to the designed underground continuous wall axis position, lay out the earthwork, lay the cushion layer after excavation, and then tie the guide wall side wall and wing plate steel bars, set up the formwork, and pour concrete; backfill the guide wall in time after removing the formwork. When the concrete strength of the guide wall reaches 75% of the designed strength, carry out trench construction, and divide the trench section into the first-stage trench and the second-stage trench; S3: Mud preparation When preparing mud, determine the mud formula based on the soil layer that is most likely to collapse; S4: Phase I trough construction; S5: Ultrasonic verticality detection; S6: Clean the bottom and change the slurry Use a combination of sedimentation and replacement methods to clean the bottom and replace the slurry; S7. Hoist the steel cage and pour concrete, and pull out the support mechanism before the concrete begins to set; S8: Phase II trench construction.

2. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 1, characterized in that: The mud in step S3 is mainly made of bentonite, anhydrous sodium carbonate as a dispersant, carboxymethyl cellulose as a fluid loss reducer, barite powder as a weighting agent, and pulp fiber as a plugging agent. The density of the newly prepared mud is 1.05-1.15 g / cm 3 , viscosity 18~22, sand content ≤4%.

3. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 1, characterized in that: The first phase trench construction process described in step S4 includes: S4.1: Divide each slot section into three sections along the length direction, namely the first slot section, the second slot section and the third slot section; S4.2: excavate the first and third trench sections to the soil-rock interface; then excavate the second trench section so that the second trench section is at least 5m higher than the first and third trench sections; S4.3: Set up support structures in the silt layer, sand layer, etc. of the excavated trench section; S4.4: Use a double-wheel milling machine to mill the first and third slot sections to the designed depth; finally, mill the second slot section to the designed depth.

4. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 1, characterized in that: In step S5, during ultrasonic testing, observe whether the verticality of the groove wall meets the requirements through the correction plates on the groove forming machine and the double-wheel groove milling machine, and perform ultrasonic testing through an ultrasonic detector to detect whether the verticality meets the requirements; if so, continue to form the groove, if not, continuously repair the groove according to the ultrasonic image and the correction prompt information on the correction plate; during ultrasonic testing, test every 5m and test at the soil layer stratification. When the verticality does not meet the requirements, correct it in time to achieve dynamic correction; during ultrasonic verticality testing, select 3 positions on the two longitudinal sections of the groove section for testing, and select 1 position on the transverse section for testing.

5. The method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations according to claim 1, characterized in that: When using the sedimentation method to clean the bottom, it is necessary to start one hour after the trench is completed and use the hydraulic grab bucket for trenching operations to directly remove the sediment at the bottom of the trench.

6. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 1, characterized in that: When using the replacement method to change the slurry, adopt pump suction reverse circulation to change the slurry. Use a crane to hang the slurry change pump 1 meter away from the bottom of the trough, start the slurry change pump, suck up the sediment at the bottom of the trough, and add slurry at the trough mouth at the same time. During the whole process of bottom cleaning and slurry change, control the balance between the amount of slurry sucked and the amount of slurry added. Do not let the slurry overflow from the trough or let the slurry surface fall below the groundwater level by more than 1m.

7. The method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations according to claim 1, characterized in that: The second-phase trench construction process described in step S8 includes milling the second-phase trench by milling. The second-phase trench is divided into a trench section and is formed at one time. The second-phase trench milling connection with the first-phase trench milling connection should be more than 30 cm. The second-phase trench construction should be carried out after the concrete strength of the first-phase trench reaches 75%.

8. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 2, characterized in that: The support mechanism includes a wheelbase adjustment component, a threaded sleeve, a connecting rod, an auxiliary positioning foot and a support component. The wheelbase adjustment component is arranged in a connecting pipe, and includes a first bevel gear, a second bevel gear and a first damping adjustment disk. The first bevel gear is installed at the end of the threaded sleeve and meshes with the second bevel gear. The second bevel gear is arranged at the end of the first damping adjustment disk coupling shaft, and the threaded sleeve is rotatably connected to the connecting pipe through a bearing.

9. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 8, characterized in that: The support assembly includes a supporting foot, a first connecting shaft, a second connecting shaft, an adjustment unit, a fixed connecting piece and a sliding connecting piece. The supporting foot is arranged at the end of the first connecting shaft, contacts with the inner wall of the supporting steel plate, and is hingedly connected to one end of the first connecting shaft. The other end of the first connecting shaft is hingedly connected to the sliding connecting piece. The sliding connecting piece is movably sleeved on the threaded sleeve through the adjustment unit, and is a movable end. The fixed connecting piece is fixedly arranged on the connecting rod through a fixing pin, and is a fixed end, and is hingedly connected to one end of the second connecting shaft. The other end of the second connecting shaft is hingedly connected to a hinge point arranged in the middle of the first connecting shaft to form a claw-like structure.

10. A method for constructing trenches for pipe-roof structures in coastal areas and ultra-thick rock formations as claimed in claim 8, characterized in that: The adjustment unit is arranged on the threaded sleeve, and includes a second damping adjustment disk, a driving member and a third spur gear. The driving member is movably arranged in the cavity of the threaded sleeve. The third spur gear is arranged in the inner cavity of the threaded sleeve through the shaft connection of the second damping adjustment disk and is meshed with a rack arranged at the tail of the driving member.

Images