Construction process of joint occlusion water stop reinforced ultra-deep hundred-meter-scale milling groove ground wall

Abstract

The invention relates to a construction process of a joint occlusion water stop reinforced ultra-deep hectometer-level milling groove ground wall. The construction process comprises the working procedure steps of grooving, groove bottom sediment treatment, reinforcement cage hoisting, guide pipe lowering, bottom sealing concrete pouring, broken stone backfilling, joint box hoisting, overall concrete pouring and the like. Grooving adopts a grabbing and milling combined process and is divided into a first-stage groove section and a second-stage groove section, the first-stage groove is designed to be full-head scutching and two-cutter grooving, H-shaped steel water stop joints are arranged at the two ends of a reinforcement cage, the reinforcement cage is fully wrapped with anti-streaming slurry stop iron sheets, after the reinforcement cage is hung in sections, bottom sealing concrete is poured, broken stones are backfilled and compacted, and pouring is continued to form a wall body. The second-stage groove is designed to be in a full-closed range, three-knife grooving is conducted, and after a wall brushing device is adopted at the joint for wall brushing, remaining procedures are completed. And the first-stage groove and the second-stage groove are constructed in a sequence of a warehouse jumping method, and a continuous wall body is formed in a circulating manner. According to the process, the existing ultra-deep casing milling joint ground wall construction process is innovated, and the problems that the casing milling joint is low in concrete milling speed, poor in water stopping effect, large in reinforcement cage hoisting weight and the like are solved.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-deep foundation pit construction in construction engineering, and in particular to a joint-engaging water-stopping reinforced ultra-deep 100-meter-level milling groove ground wall construction process. Background Art

[0002] With the deep excavation and efficient utilization of urban underground space resources, the development of shallow underground space has gradually become saturated, forcing the excavation of foundation pits to extend to deeper levels. At present, the excavation depth of deep foundation pits in soft soil areas in China has approached 60 meters, and it indicates that deeper areas will be explored in the future. This trend has put forward unprecedented high standards for the design, construction quality and safety performance of the retaining structure of deep foundation pit projects.

[0003] For ultra-deep foundation pit construction, underground continuous walls are generally used as retaining structures in China. The design depth is often twice the excavation depth of the foundation pit, which has led to the challenge of underground continuous wall construction over 100 meters deep, and has put forward a severe test on the sophistication and innovation of construction technology. The main technical bottlenecks faced by ultra-deep underground continuous wall construction include:

[0004] 1. Trenching is difficult: As the trenching depth increases, the hardness of the deep soil increases significantly. Traditional trenching machinery is difficult to reach the predetermined depth, especially in ultra-deep hard sand layers. The trenching efficiency is low or even impossible to operate effectively, which becomes a major obstacle in the early stages of construction.

[0005] 2. Complex installation of steel cages: The steel cages required for ultra-deep foundation pits are not only densely reinforced, but also much longer and heavier than normal. The technical difficulty of the lifting operation increases dramatically, and the risk factor also increases accordingly, which puts higher requirements on the performance and operating accuracy of the lifting equipment.

[0006] 3. Joint technology difficulties: The choice of joint forms is limited. Although the use of rigid joints can enhance the structural strength and water-stopping effect, it will significantly increase the weight of the steel cage, increase the burden of lifting, and put higher requirements on the lifting equipment. At the same time, it affects the bearing capacity of the foundation and the stability of the slot. In addition, the connection of rigid joints is complicated and time-consuming, which poses a threat to the quality control of the joints, especially when the soil at the joints is not thoroughly cleaned, it is difficult to ensure the safe excavation of deep foundation pits.

[0007] To address the above challenges, the industry has explored a construction solution that uses a slot milling machine to form slots and a sleeve milling joint, and optimizes the steel cage structure to reduce the weight of the hoisting and achieve controllable risks. However, this solution is not perfect and still has the following shortcomings:

[0008] 1. Risks of trench section verticality and joint quality: The second-phase trench section construction requires milling of the first-phase hard concrete. If the concrete strength on both sides is uneven, it will affect the verticality of the trench section, which may damage the first-phase steel cage and affect the joint quality. The splitting phenomenon of deep joints will endanger the overall stability of the underground continuous wall.

[0009] 2. Poor water-stopping effect of joints: The milling joints rely on the concrete joints formed by the burrs formed by milling, and the water-stopping effect is limited. The mud adhesion problem is more prominent, which affects the water-stopping performance and poses a severe challenge to the construction of ultra-deep foundation pits that need to pump out the pressure water. Although additional reinforcement water-stopping measures can be taken, the technical reliability and cost control of reinforcement water-stopping measures in deep hard soil are still difficult problems.

[0010] Therefore, how to provide a joint bite waterproof reinforced ultra-deep 100-meter milling groove ground wall construction process with low lifting risk, fast construction speed, strong wall rigidity and excellent joint waterproof performance has become a key technical problem that needs to be solved urgently. This is not only an innovation of traditional construction technology, but also an important cornerstone to ensure the safe and efficient advancement of ultra-deep foundation pit projects. Summary of the invention

[0011] The present invention provides a joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process to solve the above-mentioned technical problems.

[0012] In order to solve the above technical problems, the present invention provides a joint-engagement water-stopping reinforced ultra-deep 100-meter milling groove ground wall construction process, which is divided into a first-stage groove section and a second-stage groove section. The first-stage groove section is located on both sides, and the second-stage groove section is located between the first-stage groove sections on both sides.

[0013] The construction steps of the first phase trough section include: first phase trough section formation, trough bottom sediment treatment, first phase trough section steel cage processing and hoisting, guide tube lowering, bottom sealing concrete pouring, crushed stone backfilling, joint box hoisting and overall concrete pouring;

[0014] The construction steps of the second phase trough section include: forming the second phase trough section, treating the sediment at the bottom of the trough, brushing the wall, processing and hoisting the steel cage of the second phase trough section, lowering the conduit and pouring the whole concrete to form a unit wall;

[0015] The grooves of the first-phase groove section and the second-phase groove section are formed by a combination of grabbing and milling technology, and the walls of the first-phase groove section and the second-phase groove section are formed by a "skipping bin method" construction sequence, which is repeated to form a continuous wall;

[0016] The bottom sediment treatment of the tank adopts a slot milling machine to go down to the bottom of the tank and then perform pump suction reverse circulation slurry replacement;

[0017] Use a wall brush installed at the bucket of the slotting machine to brush the wall;

[0018] H-shaped steel waterstop joints are installed at the ends of both sides of the steel cage of the first-phase trough section, and anti-circumvention slurry-stopping iron sheets are provided on both sides of the joints; sealing steel bars are provided on both sides of the steel cage of the second-phase trough section, and the sealing steel bars are matched with the H-shaped steel waterstop joints; the steel cage is hoisted into the trough in sections, and when docking, the longitudinal steel bars are connected with extended straight threaded sleeves, and the H-shaped steel waterstop joints are connected with bolts.

[0019] Preferably, the grabbing and milling combined process includes: using a slotting machine to slot in the upper range of 0 to 10 meters of the slot section; and using a slotting machine to mill the slot to the bottom of the slot section below a depth of 10 meters.

[0020] Preferably, the first phase trench section adopts a full-width opening, with a trench width of 5 meters and a trench section width of 3 meters. A width of 1 meter is reserved on both sides of the trench section for backfilling gravel and installing the joint box. The trench is formed by two cutters, with the first cutter milling the trench width to 2.8 meters and the second cutter milling the trench width to 2.2 meters.

[0021] Preferably, the second-phase trench section adopts a fully closed width, the trench section width is 5 meters to 6 meters, and the trench is formed by three cutters. The grab and milling combined process is used to construct the middle cut first, and the cut on each side is used to grab the backfill gravel and unmilled soil with the trenching machine grab bucket. For the area at the joint that cannot be grabbed and milled, the backfill gravel is shoveled out with the wall brush and the trench section is grabbed out with the grab bucket. After the second-phase trench section is formed, the wall brush is used to perform wall brushing construction at the joint.

[0022] Preferably, the H-shaped steel waterstop joint includes an H-shaped steel consisting of a web and two flanges, and a waterstop steel plate installed in the middle of the web.

[0023] Preferably, the anti-bypass and slurry-stopping iron sheets are installed on the H-shaped steels on both sides of the steel cage of the first-phase trough section, and are arranged from the top of the steel cage to the bottom of the cage. The anti-bypass and slurry-stopping iron sheets are 4 pieces with a width of 1.5 meters, covering and wrapping the entire steel cage.

[0024] Preferably, the joint box is a two-piece independent type, one end of the joint box is inserted into the groove formed by the water stop steel plate and the flange, fully contacting the web, and the other side supports the soil.

[0025] Preferably, the waterstop steel plate has a thickness of 14 mm and a width of 400 mm.

[0026] Preferably, the gravel backfill height is below 5 meters of the excavation surface and avoids 3 meters of the connection position.

[0027] Preferably, the crushed stone is made of recycled stone with a particle size of not less than 5 cm; the crushed stone is not packed in woven bags and then backfilled.

[0028] Compared with the prior art, the joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process provided by the present invention has the following advantages:

[0029] 1. The present invention adopts the combined grabbing and milling process, combines the advantages of the slotting machine and the slot milling machine, effectively solves the problem of high hardness of deep soil and difficulty in slotting, and solves the problem that the second-stage slot section of the conventional sleeve milling joint ground wall needs to be slotted with the hard concrete of the first-stage slot section, significantly improves the slotting efficiency and shortens the construction period;

[0030] 2. The present invention adopts H-shaped steel water stop joints, reduces the overall weight of the steel cage by reducing the width of the first-phase trench section ground wall steel cage, realizes the use of rigid joints for ultra-deep ground walls, and ensures tight engagement at the joints between the first-phase trench and the second-phase trench, thereby reducing the risk of hoisting and ensuring the connection strength and water stop effect of the joints; in addition, through strict trench quality control and gravel backfilling measures, the overall rigidity and stability of the underground continuous wall are further enhanced, effectively preventing the occurrence of safety accidents such as trench wall collapse;

[0031] 3. The present invention can effectively handle the backfilled gravel, mud, disturbed mortar, etc. at the joints through the use of the wall brush, further improving the joint quality and providing a strong guarantee for the excavation of deep foundation pits;

[0032] 4. The construction process of the present invention is applicable to a variety of geological conditions and engineering requirements, and performs particularly well in ultra-deep foundation pit construction in soft soil areas and high-hardness soil layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of the joint bite water-stop reinforced ultra-deep 100-meter milling groove ground wall construction process in a specific embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of the construction steps of a first-stage trench section in a specific implementation manner of the present invention;

[0035] Figure 3 It is a schematic diagram of the construction steps of the second phase trench section in a specific implementation manner of the present invention;

[0036] Figure 4 It is a schematic diagram of a second-stage slot section slot grab and wall brush in a specific embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the wall-forming sequence of the "skipping bin method" in a specific implementation mode of the present invention;

[0038] Figure 6 It is a cross-sectional schematic diagram of a first-stage trench section ground wall in a specific implementation manner of the present invention;

[0039] Figure 7It is a structural schematic diagram of an H-shaped steel water stop joint in a specific embodiment of the present invention;

[0040] Figure 8 for Figure 7 Enlarged view of part A.

[0041] In the figure: 10-first phase trough section steel cage, 20-second phase trough section steel cage, 21-sealing steel bar, 30-H-shaped steel waterstop joint, 31-flange, 32-web, 33-waterstop steel plate, 34-first angle steel, 35-second angle steel, 36-layer steel plate, 40-anti-bypass slurry stop iron sheet, 50-bottom sealing concrete, 51-conduit, 60-gravel, 70-joint box, 80-trench machine grab, 90-wall brush. DETAILED DESCRIPTION

[0042] In order to describe the technical solution of the above invention in more detail, specific embodiments are listed below to demonstrate the technical effects; it should be emphasized that these embodiments are used to illustrate the present invention but not to limit the scope of the present invention.

[0043] The joint bite water-stop reinforced ultra-deep 100-meter-class milling groove ground wall construction process provided by the present invention is as follows: Figures 1 to 8 As shown, it is divided into a first-phase slot section and a second-phase slot section, the first-phase slot section is located on both sides, and the second-phase slot section is located between the first-phase slot sections on both sides, wherein:

[0044] The construction steps of the first-phase trough section include: troughing of the first-phase trough section, treatment of trough bottom sediment, processing and hoisting of the first-phase trough section steel cage 10, lowering of the conduit 51, pouring of bottom concrete 50, backfilling of crushed stone 60, hanging of the joint box 70 and integral concrete pouring. Specifically, after the first-phase trough section steel cage 10 is hoisted into place, the conduit 51 is placed to pour the bottom concrete 50, and then the crushed stone 60 is backfilled, the joint box 70 is hung to compact the crushed stone 60, and after the joint box 70 is hung in place, the gap between the joint box 70 and one side of the soil is backfilled with crushed stone 60, and the integral concrete is poured to form a unit wall.

[0045] The construction steps of the second phase trough section include: forming the second phase trough section, treating the sediment at the bottom of the trough, brushing the wall, processing and hoisting the steel cage 20 of the second phase trough section, lowering the guide tube 51 and pouring the whole concrete to form a unit wall. Specifically:

[0046] The grooves of the first-phase groove section and the second-phase groove section are formed by a grab-milling combined process, and the first-phase groove section and the second-phase groove section wall are formed by a "skipping bin method" construction sequence, and a continuous wall is formed in a cycle. The present invention adopts a grab-milling combined process, combines the advantages of a groove forming machine and a groove milling machine, effectively solves the problem of high hardness of deep soil and difficulty in groove formation, and solves the problem that the second-phase groove section of the conventional sleeve milling joint ground wall groove must be milled with hard concrete of the first-phase groove section, significantly improves the groove efficiency, and shortens the construction period.

[0047] The sludge treatment at the bottom of the tank adopts a slot milling machine to go down to the bottom of the tank and then perform pump suction reverse circulation slurry replacement.

[0048] The wall brushing device 90 installed at the trenching machine grab 80 is used for wall brushing. The wall brush 90 is matched with the H-shaped steel water stop joint 30, and can realize the process requirements of backfilling gravel 60 at the shovel-drop joint and brushing the wall of the joint, thereby effectively handling the backfill gravel, mud, disturbing mortar, etc. at the joint, further improving the joint quality, and providing a strong guarantee for the excavation of deep foundation pits.

[0049] Since the steel cage in this embodiment is an extra-long and extra-heavy steel cage of the hundred-meter level, H-shaped steel waterstop joints 30 are installed at the ends of both sides of the first-phase trough section steel cage 10, and anti-circumvention slurry-stopping iron sheets 40 are provided on both sides of the joints; sealing steel bars 21 are provided on both sides of the second-phase trough section steel cage 20, and the sealing steel bars 21 match the H-shaped steel waterstop joints 30. In this embodiment, the sealing steel bars 21 are "M"-shaped; the steel cage (including the first-phase trough section steel cage 10 and the second-phase trough section steel cage 20) are hoisted into the trough in sections. When docking, the longitudinal steel bars are quickly connected with extended straight threaded sleeves. The number of steel bar joints of the same section is staggered according to the requirements of the specifications, and the H-shaped steel waterstop joints 30 are connected with bolts. The H-shaped steel water-stop joint 30 adopted in the present invention can reduce the overall weight of the steel cage by reducing the width of the steel cage of the first-phase trough section ground wall, thereby realizing the use of a rigid joint for an ultra-deep ground wall, while ensuring that the joints between the first-phase trough section and the second-phase trough section are tightly engaged, thereby reducing the risk of lifting and ensuring the connection strength and water-stopping effect of the joint.

[0050] The present invention has shown remarkable beneficial effects in improving construction efficiency, enhancing the safety of enclosure structures, optimizing joint waterproofing effects, reducing construction costs and environmental impacts, and improving construction flexibility and adaptability, and is of great significance for promoting the in-depth development and utilization of urban underground space.

[0051] In some embodiments, the combined grabbing and milling process includes: using a slotting machine to open slots in the upper 0 to 10 meter range of the slot section to allow the milling bucket of the slot milling machine to enter the slot section, and using a slot milling machine to mill slots to the bottom of the slot section below a depth of 10 meters to ensure that the verticality of the slot reaches 1 / 1000.

[0052] In some embodiments, please refer to Figure 2 The first phase trench section adopts a full-width opening, with a trench width of 5 meters and a trench section width of 3 meters. A width of 1 meter is reserved on both sides of the trench section for backfilling gravel 60 and installing the joint box 70. The trench is formed by two cutters. The first cutter mills the trench with a width of 2.8 meters and the second cutter mills the trench with a width of 2.2 meters.

[0053] In some embodiments, please refer to Figure 3 and Figure 4 The second-phase trench section adopts a fully closed width, the trench section width is 5 meters to 6 meters, and the trench is formed by three cutters. The grab and milling combined process is adopted to first construct a middle cut, and then a cut on each side. The trenching machine grab bucket 80 is used to grab the backfill gravel 60 and the unmilled soil. For the area where grab milling cannot be carried out at the joint, the backfill gravel 60 is shoveled by the wall brush 90, and the trench section is grabbed by the grab bucket. After the second-phase trench section is formed, the wall brush 90 is used to perform wall brushing construction at the joint.

[0054] In some embodiments, please refer to Figure 5 The construction sequence of the "skipping method" is as shown in the slot section numbering as 1→3→5→2→7→4... (odd numbers are first-phase slot sections, even numbers are second-phase slot sections). The second-phase slot section can only be started 24 hours after the first-phase slot sections on both sides are completed.

[0055] In some embodiments, please refer to Figure 6 and Figure 7 The H-shaped steel water stop joint 30 includes an H-shaped steel composed of a web 32 and two flanges 31 (the height of the H-shaped steel is selected according to the designed slot section and should be less than the slot section width) and a water stop steel plate 33 installed in the middle of the web 32. Specifically, the water stop steel plate 33 is fully welded with the web 32 to improve the water stop effect at the H-shaped steel joint; in addition, the connection between the water stop steel plate 33 and the web 32 is welded with a first angle steel 34 to ensure the connection strength between the water stop steel plate 33 and the H-shaped steel. In some embodiments, the thickness of the water stop steel plate 33 is 14 mm and the width is 400 mm.

[0056] In some embodiments, please refer to Figure 2 as well as Figures 6 to 8The anti-bypass and slurry-stopping iron sheet 40 is installed on the H-shaped steel on both sides of the first-stage slot section steel cage 10, and is set from the top of the steel cage to the bottom of the cage. The anti-bypass and slurry-stopping iron sheet 40 is 4 pieces, with a width of 1.5 meters, covering and wrapping the entire steel cage. While preventing the concrete mortar from bypassing and entering the joint box 70 outside the H-shaped steel and the gravel 60 backfill area, it can also prevent the backfill gravel 60 from entering the first-stage slot section steel cage 10, thereby affecting the quality of the concrete of the ground wall. Specifically, the second angle steel 35 is welded on the flange 31, and a bolt hole is set on the second angle steel 35 every 50 cm. The anti-bypass and slurry-stopping iron sheet 40 is fixed to the H-shaped steel water stop joint 30 by bolting using a layering steel plate 36.

[0057] In some embodiments, please refer to Figure 6 In the above-mentioned method of lifting the steel cage into the slot in sections, the steel cage top section position should be set 5 meters or deeper below the bottom plate surface of the foundation pit. In addition, because other conditions cannot meet the above-mentioned section position requirements, the section position should avoid the range of 5 meters above and below the bottom plate surface. Then, according to the weight and length of the section cage, appropriate lifting equipment is selected, and the steel cage is lifted into the slot by a double-machine lifting method. The present invention reduces the dependence on large-scale lifting equipment by optimizing the construction process and reducing the lifting risk, thereby reducing the construction cost.

[0058] In some embodiments, the backfill height of the crushed stone 60 is below the depth of 5 meters from the excavation surface and avoids the range of 3 meters from the connection position, so as to prevent the huge lateral pressure formed by the concrete pouring from causing the weak joint of the I-beam to be stretched open, causing the concrete to flow into the backfill section, affecting the formation of the second phase slot section; in some embodiments, the crushed stone 60 can be made of recycled stone, which not only saves resources but also reduces waste emissions, conforms to the concept of green construction, and reduces construction costs and environmental impacts. The particle size of the stone is not less than 5 cm, and in this embodiment, it is 5 to 10 cm, so as to prevent the crushed stone 60 from flowing into the steel cage with too small a particle size and affecting the quality of the wall; in addition, the crushed stone 60 is not backfilled after bagging in woven bags, so as to prevent the woven bags from clogging the sand suction port and slurry pipe of the slot milling machine, resulting in failure to mill the slot normally.

[0059] In some embodiments, please refer to Figure 2 The joint box 70 is a two-piece independent type. One end of the joint box 70 is inserted into the groove formed by the waterstop steel plate 33 and the flange 31, and is in full contact with the web 32. The other side of the joint box 70 supports the soil and transmits the lateral pressure formed by pouring concrete to the soil, thereby preventing the H-shaped steel waterstop joint 30 from deviating and affecting the quality of the joint.

[0060] The above construction technology is suitable for a variety of geological conditions and engineering requirements, especially in ultra-deep foundation pit construction in soft soil areas and high-hardness soil layers. Through flexible joint forms and steel cage processing methods, it can be adjusted and optimized according to specific engineering conditions, improving the flexibility and adaptability of construction.

[0061] In summary, the joint-engaging waterproof reinforced ultra-deep 100-meter milling groove ground wall construction process provided by the present invention not only overcomes the problems of slow milling speed of hard concrete and poor seam waterproofing effect of the sleeve milling joint, but also solves the problem that the rigid joint ground wall steel cage has a large hoisting weight, complex operation, high risk, and is not suitable for ultra-deep underground continuous wall construction. The underground continuous wall formed by this method has the advantages of controllable hoisting risk, fast wall construction speed, high wall rigidity, and good seam waterproofing effect. While ensuring that the impact of the surrounding environment is controllable, the depth of the ultra-deep foundation pit can be further deepened.

[0062] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A joint-engagement water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process, characterized in that: It is divided into a first-stage trough section and a second-stage trough section, wherein the first-stage trough section is located at both sides, and the second-stage trough section is located between the first-stage trough sections at both sides. The construction steps of the first phase trough section include: first phase trough section formation, trough bottom sediment treatment, first phase trough section steel cage processing and hoisting, guide tube lowering, bottom sealing concrete pouring, crushed stone backfilling, joint box hoisting and overall concrete pouring; The construction steps of the second phase trough section include: forming the second phase trough section, treating the sediment at the bottom of the trough, brushing the wall, processing and hoisting the steel cage of the second phase trough section, lowering the conduit and pouring the whole concrete to form a unit wall; The grooves of the first-phase groove section and the second-phase groove section are formed by a combination of grabbing and milling technology, and the walls of the first-phase groove section and the second-phase groove section are formed by a "skipping method" construction sequence, which is repeated to form a continuous wall; The bottom sediment treatment of the tank adopts a slot milling machine to go down to the bottom of the tank and then perform pump suction reverse circulation slurry replacement; Use a wall brush installed at the bucket of the slotting machine to brush the wall; H-shaped steel waterstop joints are installed at the ends of both sides of the steel cage of the first-phase trough section, and anti-circumvention slurry-stopping iron sheets are provided on both sides of the joints; sealing steel bars are provided on both sides of the steel cage of the second-phase trough section, and the sealing steel bars are matched with the H-shaped steel waterstop joints; the steel cage is hoisted into the trough in sections, and when docking, the longitudinal steel bars are connected with extended straight threaded sleeves, and the H-shaped steel waterstop joints are connected with bolts.

2. The joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process according to claim 1 is characterized in that: The grabbing and milling combined process includes: using a slotting machine to slot in the upper range of 0 to 10 meters of the slot section; and using a slotting machine to mill the slot to the bottom of the slot section below a depth of 10 meters.

3. The joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process as claimed in claim 2 is characterized in that: The first phase trench section adopts a full-width opening, with a trench width of 5 meters and a trench section width of 3 meters. A width of 1 meter is reserved on both sides of the trench section for backfilling gravel and installing the joint box. The trench is formed by two cutters. The first cutter mills the trench with a width of 2.8 meters and the second cutter mills the trench with a width of 2.2 meters.

4. The joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process as claimed in claim 3 is characterized in that: The second-phase trench section adopts a fully closed width, with a trench section width of 5 meters to 6 meters. The trench is formed by three cutters. The grab and milling combined process is used to first construct the middle cut, and then the two sides are cut by the trenching machine grab bucket to grab the backfill gravel and unmilled soil. For the area where grab milling cannot be carried out at the joint, the backfill gravel is shoveled out by the wall brush and the trench section is grabbed out by the grab bucket. After the second-phase trench section is formed, the wall brush is used to carry out wall brushing construction at the joint.

5. The joint-engagement water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process according to claim 1 is characterized in that: The H-shaped steel water stop joint comprises an H-shaped steel consisting of a web and two flanges and a water stop steel plate installed in the middle of the web.

6. The joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process as claimed in claim 5 is characterized in that: The anti-bypass and slurry-stopping iron sheets are installed on the H-shaped steels on both sides of the steel cage of the first phase trough section, and are set from the top of the steel cage to the bottom of the cage. The anti-bypass and slurry-stopping iron sheets are 4 pieces with a width of 1.5 meters, covering and wrapping the entire steel cage.

7. The joint-engagement water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process as claimed in claim 5 is characterized in that: The joint box is of two independent pieces, one end of which is inserted into the groove formed by the water stop steel plate and the flange, in full contact with the web, and the other end of which supports the soil.

8. The joint-engagement water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process as claimed in claim 5 is characterized in that: The thickness of the waterstop steel plate is 14 mm and the width is 400 mm.

9. The joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process according to claim 1 is characterized in that: The gravel backfill height is below 5 meters from the excavation surface and avoids a range of 3 meters from the connection position.

10. The joint-engaging water-stopping reinforced ultra-deep 100-meter-class milling groove ground wall construction process according to claim 9, characterized in that: The crushed stone is made of recycled stone with a particle size of not less than 5 cm; the crushed stone is not packed in woven bags and then backfilled.

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