A method of construction of a containment having a containment wall

Abstract

The application provides a retaining wall construction method, which comprises the following steps: S1, breaking the ground between the existing retaining wall and the existing building to be reconstructed; S2, constructing a temporary support structure close to one side of the existing retaining wall; S3, excavating the soil between the temporary support structure and the existing building to the surface of the outer expansion slab; S4, segmenting the foundation wing plate of the outer expansion slab at a predetermined position, and constructing an isolation pile at the segmented position based on the static pressure of an anchor rod; and S5, backfilling the soil between the temporary support structure and the existing building. The temporary support structure and the isolation pile are combined to form a double protection system, which is specifically adapted to the special working condition that the existing retaining wall is pressed above the outer expansion slab, avoids the instantaneous impact of directly excavating and cutting the outer expansion slab on the retaining wall, and realizes the early protection of the retaining wall and the partition isolation of the soil in two lines of defense, thereby solving the problem that the shallow foundation retaining wall is easily cracked and tilted due to soil disturbance from the root.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for constructing an enclosure for existing walls. Background Technology

[0002] In recent years, an increasing number of old buildings have needed reinforcement and renovation to extend their service life due to problems such as age, structural damage, construction that does not meet current standards, and uneven foundation settlement.

[0003] The old buildings are mostly surrounded by walls and other structures, and the renovation and reconstruction process has a significant impact on the surrounding environment, requiring isolation and protection. In particular, due to uneven settlement and tilting of existing high-rise buildings on the site, it is necessary to excavate the foundation soil to correct the tilt. However, the existing wall is adjacent to the outer contour line of the main structure, and the basement floor slab extends beyond the edge line of the main structure, resulting in the wall being located above the extended base slab. Furthermore, residential buildings are adjacent to the outside of the wall, therefore, targeted protection of both the wall and the residences is necessary to prevent damage or collapse of the wall.

[0004] However, perimeter walls are typically built on shallow foundations or strip foundations, resulting in low structural strength and extreme sensitivity to soil deformation. They are highly susceptible to cracking, tilting, or even collapse due to soil disturbance, stress release, and soil squeezing effects caused by construction. For existing perimeter walls located adjacent to the construction site, situated above the extended base slab, the difficulty of perimeter wall construction is further increased.

[0005] Therefore, how to carry out targeted protection construction on existing walls adjacent to existing building renovation construction sites has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a construction method for protecting existing walls, which can provide targeted protection and isolation for existing walls adjacent to existing building renovation construction sites.

[0007] To solve the above-mentioned technical problems, the present invention provides a method for constructing an enclosure for an existing wall, the method comprising:

[0008] S1. Remove the ground level between the existing wall and the existing building to be renovated;

[0009] S2. Construction of temporary support structures close to one side of the existing wall;

[0010] S3. Excavate the earthwork between the temporary support structure and the existing building down to the surface of the outer base slab;

[0011] S4. Divide the foundation wing plate of the outer expansion base plate at the predetermined position, and construct isolation piles at the divided position based on the static pressure of the anchor bolts.

[0012] S5. Backfilling of earthwork between the temporary support structure and the existing building.

[0013] Optionally, in the aforementioned method for constructing an existing wall enclosure, step S2 includes the following steps:

[0014] S21. Construct retaining piles close to one side of the wall, with the top elevation of the retaining piles being consistent with the top elevation of the existing wall foundation.

[0015] S22. Construct walers at the top of the retaining piles and the foundation of the existing wall; the retaining piles and the walers at their tops together form a temporary support structure.

[0016] Optionally, in the construction method for the protection of the existing wall, in S22, a concrete waler is constructed at the top of the retaining piles and the top of the foundation of the existing wall.

[0017] Optionally, in the aforementioned method for constructing the retaining wall, in step S21, the construction of retaining piles close to one side of the wall includes:

[0018] Along the outer contour line of the retaining piles, water drills are used to drill circumferential holes to partially divide the foundation wing plate of the outward-expanding base plate along this contour.

[0019] The retaining piles are vertically lowered into the hole until they reach the predetermined depth.

[0020] Optionally, in the construction method for the existing wall enclosure, the bottom elevation of the isolation pile after construction in S4 is lower than the bottom elevation of the temporary support structure after construction in S2.

[0021] Optionally, in the construction method for the existing wall enclosure, in S4, the isolation pile is formed by two channel steels interlocking in opposite directions, welded in sections, and the joints of adjacent channel steels are staggered vertically.

[0022] Optionally, in the construction method for the protection of the existing wall, in S4, the isolation pile is located outside the temporary support structure and on the side adjacent to the existing building.

[0023] Optionally, in the existing wall enclosure construction method, in S4, the isolation pile extends down to the stable original soil layer below the bottom surface of the outward expansion base plate.

[0024] In the construction method for the protection of existing walls provided by this invention, the construction method includes: S1, breaking down the ground between the existing wall and the existing building to be renovated; S2, constructing a temporary support structure close to one side of the existing wall; S3, excavating the soil between the temporary support structure and the existing building to the surface of the extended base slab; S4, dividing the foundation wing plate of the extended base slab at a predetermined position, and constructing isolation piles at the divided position based on the static pressure of anchor bolts; S5, backfilling the soil between the temporary support structure and the existing building. The combination of temporary support structure and isolation piles forms a dual protection system, specifically adapted to the special working condition of "the wall pressing on top of the extended base slab," avoiding the instantaneous impact of direct excavation and cutting of the extended base slab on the wall. Two lines of defense are used to achieve initial protection of the wall and zoned isolation of the soil, solving the problem of shallow foundation walls being prone to cracking and tilting due to soil disturbance from the structural root. Attached Figure Description

[0025] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0026] Figure 1 This is a schematic plan view of the enclosure construction method based on an existing wall in one embodiment of the present invention after construction;

[0027] Figure 2 This is a schematic cross-sectional view of the enclosure construction method based on an existing wall in one embodiment of the present invention after construction.

[0028] Figure 3 This is a schematic diagram of step S1 in the construction method for the enclosure of an existing wall in one embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of step S21 in the construction method for the enclosure of an existing wall in one embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of step S22 in the construction method for the enclosure of an existing wall in one embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of step S3 in the construction method for the enclosure of an existing wall in one embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of step S4 in the construction method for the enclosure of an existing wall in one embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram of step S5 in the construction method for the enclosure of an existing wall in one embodiment of the present invention.

[0034] In the picture:

[0035] 1-Existing wall; 3-Temporary support structure; 31-Retaining piles; 32-Wall; 4-Isolation piles. Detailed Implementation

[0036] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the existing wall enclosure construction method proposed by this invention. The advantages and features of this invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0037] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0038] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Research has revealed significant difficulties in constructing the retaining wall adjacent to the construction site. The key issue is that the existing wall is not an independent structure but rather situated above the building's extended foundation slab. This spatial location presents several problems with conventional retaining wall construction methods: firstly, the space for constructing retaining piles is limited by the extended foundation slab, making it difficult to arrange them properly outside the existing wall; secondly, the force transmission path between the retaining system and the existing wall's foundation is obstructed, preventing the formation of effective overall support. Existing technologies lack specific design considerations for this type of situation, significantly increasing construction difficulty. Therefore, achieving effective retaining wall protection under the condition of coexistence between the extended foundation slab and the existing wall's foundation has become a pressing technical challenge for those skilled in the art. The construction method of this invention addresses this technical challenge, effectively overcoming the aforementioned difficulties and achieving reliable retaining wall protection under the condition of coexistence between the extended foundation slab and the existing wall's foundation.

[0042] The construction method for protecting existing walls proposed in this invention can effectively solve the problem of protection construction when the wall is located above the foundation slab of the expansion. This construction method is an operable and implementable protection construction method, so as to provide targeted protection and isolation for existing walls adjacent to the construction site.

[0043] Please refer to Figures 1 to 8 The construction method for the existing wall enclosure includes:

[0044] First, please refer to Figure 3 Execute step S1 to break down the ground between the existing wall 1 and the existing building to be renovated.

[0045] Next, step S2 is performed, and the temporary support structure 3 is constructed close to one side of the existing wall 1.

[0046] Specifically, the temporary support structure 3 includes retaining piles 31 and walers 32 formed on top of them. Please refer to [reference needed]. Figure 4 and Figure 5 S2 includes the following steps:

[0047] S21. Construct retaining piles 31 close to one side of the existing wall, with the top elevation of the retaining piles 31 consistent with the top elevation of the foundation of the existing wall 1 (e.g., Figure 4 (As shown). Understandably, the type of retaining pile 31 here needs to be selected according to the actual site conditions.

[0048] Here, "closely attached" refers to the process layout logic, meaning that the retaining piles are placed at the nearest construction location inside the wall, arranged parallel to the direction of the wall, with no extra setback distance. The priority is to shorten the horizontal distance between the retaining piles and the wall foundation, maximize the lateral support stiffness, and reduce the lateral displacement of the wall; it does not mean that there is no physical gap and the pile body is directly attached to the wall concrete.

[0049] In this example, the type 31 retaining piles used can be selected based on the actual situation (applicable site width 1.5m~2.5m), for example:

[0050] ① Steel pipe retaining piles: Small clamp-type static pressure pile driving machine anchor rod static pressure;

[0051] ②Small split high-pressure jet grouting piles with retaining components: jet grouting water stop + micro steel pipe piles / channel steel piles for retaining, small crawler drilling rig + high-pressure grouting system;

[0052] ③Small bored piles + single-pipe jet grouting between piles: Small rotary drilling rigs are used to construct bored piles, and jet grouting between piles is used for water stoppage, which can be used as permanent support.

[0053] ④ Channel steel close-packed piles + inter-pile sleeve valve pipe grouting and water sealing: small vibratory hammer / small static pressure equipment directly sinks the channel steel, and small jet grouting and grouting are used to seal the gaps after the piles / between the piles.

[0054] The reason for setting the top elevation of the retaining pile 31 to be consistent with the top elevation of the existing wall 1 foundation is as follows: A reinforced concrete waler is installed on top of the retaining pile 31, and the waler 32 synchronously connects the top of the retaining pile 31 to the top surface of the wall foundation. Only when the two are at the same elevation can the waler 32 form a continuous and complete overall constraint structure. This arrangement has the following advantages:

[0055] 1) Ensure the overall coordinated force bearing of the walers, fully cover and protect the top of the wall piles and the top surface of the wall foundation. When pouring the full-length concrete walers, all the tops of the retaining piles and the top surface of the wall foundation can be attached at the same time, connecting the scattered and independent retaining piles into an overall rigid support frame, forming an all-round lateral wrapping support for the shallow foundation wall, and avoiding local stress concentration.

[0056] 2) Block the bypass channel of the upper soil and realize that the full-height isolation wall is a shallow strip foundation. If the top of the retaining pile is lower than the top of the wall foundation, a through soil channel will be formed from the ground to the top surface of the wall foundation. The soil slippage and stress of the excavated pit will go around from the top of the pile to the base of the wall, causing uneven settlement and cracks. After the elevation is consistent, the lateral support barrier goes directly from the base to the top surface of the foundation without gaps to block the transmission of disturbance.

[0057] 3) Matching the working condition of the wall located above the extended base plate: The wall is pressed on the extended base plate, the excavation working surface is controlled on the top surface of the base plate, the pile top is aligned with the top of the wall foundation, the excavation and cutting of the base plate will not over-excavate and disturb the original foundation of the wall, and reduce the disturbance of the wall foundation during construction.

[0058] 4) Uniformly control the deformation of the wall. The top of the retaining piles along the entire length of the wall is at the same elevation. Lateral constraints are applied simultaneously, and the earth pressure is evenly distributed to avoid local unilateral pushing of the wall, which can cause tilting and cracks.

[0059] Specifically, in S21, the construction of retaining piles 31 close to one side of the wall includes:

[0060] S211. Along the outer contour line of the retaining pile 31, use a water drill to drill circumferential holes to partially divide the foundation wing plate of the outer expansion base plate along the contour line.

[0061] S212. Vertically hoist the retaining pile 31 into the hole until it reaches the predetermined depth.

[0062] S22, construct the waler 32 at the top of the retaining piles 31 and the foundation top of the existing wall 1 (e.g. Figure 5 (As shown); the retaining piles 31 and the waler 32 on top of them together constitute the temporary support structure 3. In this embodiment, the waler 32 is preferably a concrete waler.

[0063] By binding steel bars to the top of the retaining piles 31 and pouring concrete to form a waler, the tops of the dispersed retaining piles 31 are connected into a whole based on the waler. The waler forms a closed connection to form a crown beam structure with high overall rigidity, which effectively constrains the displacement of the pile tops, reduces the lateral deformation of the pile body, and improves the ability of the support system to resist soil / water pressure. In addition, the foundation of the existing wall participates in the overall stress through rigid connection with the waler, and no longer bears the lateral pressure of the foundation pit alone. This can effectively prevent the wall from cracking and tilting due to lateral pressure or differential settlement, and achieve the isolation and protection of the existing structure to be protected.

[0064] In addition, the top surface of the waler can provide an installation benchmark for the anchor bolt static pressure reaction frame and monitoring points, which facilitates the completion of subsequent static pressure construction of retaining piles and the observation of support status within the limited construction space.

[0065] Next, please refer to Figure 6 Execute step S3 to excavate the earthwork between the temporary support structure 3 and the existing building down to the surface of the outer base plate.

[0066] In other words, the soil located between the temporary support structure 3 and the existing building above the extended foundation slab is excavated to expose the foundation wing plate of the extended foundation slab, thereby creating a working surface for the construction of the direct-insertion isolation piles 4.

[0067] Next, please refer to Figure 7 In step S4, the foundation wing plate of the expanded base slab is divided at a predetermined location, and isolation piles 4 are constructed at the divided locations based on the static pressure of the anchor bolts. Here, the isolation piles 4 extend to the stable undisturbed soil layer below the bottom surface of the expanded base slab. After construction, the bottom elevation of the isolation piles 4 is lower than the bottom elevation of the temporary support structure 3 after construction in step S2, so as to ensure that the retaining piles provide lateral support throughout the entire excavation stage and prevent unrestrained lower parts and soil flow around the pile bottom from disturbing the foundation of the retaining wall.

[0068] The selection of the design elevation of the bottom of the isolation pile must meet the following requirements:

[0069] 1) Vertical embedment stability requirements: The bottom of the retaining piles must penetrate deep into the original soil layer below the foundation of the retaining wall to form a sufficient embedment depth. The soil embedment is used to resist the lateral earth pressure and soil squeezing effect generated by excavation, prevent the retaining piles from sliding or overturning, and thus avoid the retaining wall from tilting and cracking.

[0070] 2) The bottom elevation of the isolation piles is lower than the elevation of the excavation working face. The bottom elevation of the isolation piles must be lower than the working elevation of the subsequent earthwork excavation to the outer expansion base plate, so as to ensure that the retaining piles play a lateral support role throughout the entire excavation stage and that there will be no unrestrained lower part and the soil flowing around the bottom of the piles, disturbing the foundation of the retaining wall.

[0071] 3) The retaining piles, adapted to the overall protective height, extend from the stable soil layer under the expanded base slab to the top surface of the retaining wall foundation, forming a complete lateral support barrier. The pile bottoms must not be suspended or remain within backfill or loose fill; they must be situated in a dense, original soil layer to ensure long-term support rigidity. Furthermore, the isolation piles 4 are located outside the temporary support structure 3 and adjacent to the existing building. The isolation piles are preferably channel steel, with adjacent channel steels interlocked and welded in sections, and the joints of adjacent channel steels are staggered vertically.

[0072] The isolation pile of this invention uses two channel steels interlocked in opposite directions, welded in sections, and continuously arranged to form a continuous vertical steel retaining wall, replacing a single independent channel steel. This arrangement has the following advantages:

[0073] 1) A closed and continuous retaining wall is formed, with no soil leakage channels. If there are lateral gaps in a single channel steel, the soil on the side of the foundation pit and groundwater will flow through the gaps to the bottom of the wall. After the front and back are interlocked, the flanges of the channel steel overlap to seal the gaps, forming a continuous isolation barrier that is impermeable to soil and water, completely blocking the slippage and seepage of soil on both sides, and achieving complete separation of soil layers.

[0074] 2) The overall cross-sectional stiffness is greatly improved. The moment of inertia and bending strength of the combined cross-section after the positive and negative interlocking are much higher than those of a single channel steel. It is not easy to bend or deform laterally under the deep earth pressure below the expanded base plate. The stiffness of a single channel steel is insufficient, and it is easy to bend and bulge under deep earth pressure, resulting in isolation failure.

[0075] 3) Convenient assembly and static pressure construction. The standard profile of the channel steel that is compatible with the static pressure process of anchor bolts can be directly spliced ​​on site. The front and back interlocking relies on the natural interlocking of the profile steel itself, without the need for additional complex locking. The sections are statically pressed into the cut bottom plate holes, which is simple to assemble and does not require customized irregular components, making the construction operation highly operable.

[0076] 4) The joints are self-locking, providing stronger resistance to slippage. The interlocking of the channel steel on both sides prevents the pile from laterally separating under horizontal and vertical soil thrust. Compared to parallel independent channel steel, this design offers better overall integrity and long-term support stability. Ideally, the joints of adjacent channel steels are staggered vertically to avoid them being at the same horizontal level. This arrangement has the following advantages:

[0077] 1) Avoid forming weak sections at the same height and evenly distribute the stress. Each welded joint is a weak point in the structure. The bending and shear bearing capacity of the weld is lower than that of the channel steel base material. After being staggered, only a single channel steel has a joint at the same horizontal section. There will be no situation where the entire row of piles is welded at the same elevation. The overall support stiffness is uniform and continuous.

[0078] 2) Improve the overall resistance to overturning and bending. The lateral earth pressure of the foundation pit is distributed along the entire height of the pile. If the welds are dispersed at different elevations, they will not concentrate at a certain height to form a weak zone. The pile body is not easy to bend or break at that height.

[0079] 3) Blocking horizontal flow of soil along the joint: If all joints are flush, a continuous horizontal gap will be formed at the same height, allowing soil and groundwater to flow laterally along the entire joint, thus destroying the soil isolation effect; after staggering the joints, the joints are distributed in a staggered manner, without a continuous horizontal seepage channel.

[0080] By constructing isolation piles, the surrounding soil is isolated from the soil under the foundation of the existing building to be constructed. As a protective isolation structure for the existing wall 1, the isolation piles prevent the lateral pressure and micro-vibration generated by the existing building during the renovation and reconstruction process from being transmitted to the adjacent existing wall (i.e., reducing the impact on the surrounding environment), avoiding uneven settlement or cracking of the existing wall, and achieving safe isolation under confined space construction.

[0081] Next, please refer to Figure 8 Then, proceed with step S5 to backfill the earthwork between the temporary support structure 3 and the existing building.

[0082] To better understand the principle of how the existing wall protection construction method of the present invention achieves the protection of the existing wall, the working principles of the temporary support structure (first protection) and the isolation piles (second protection) that constitute the entire protection system of the wall will be described in detail below.

[0083] For temporary support structures:

[0084] 1) Role: The lateral protection of the first pre-construction wall is constructed before all other processes such as earthwork excavation, base plate cutting, and isolation pile construction. It forms lateral rigid support for the shallow foundation wall in advance, offsetting the lateral thrust generated by excavation unloading and soil squeezing, preventing the wall from cracking, tilting, and collapsing from the source, and making up for the shortcomings of traditional processes that do not have pre-construction wall protection.

[0085] 2) The retaining piles form an integral support system with the concrete walers. As vertical load-bearing components, after the continuous concrete walers are poured on top, all the individual retaining piles are connected into a whole, which greatly improves the overall support rigidity, evenly distributes the soil pressure, and avoids overload of individual piles.

[0086] 3) Preventing lateral slippage of surface soil: Before the construction of isolation piles, retaining piles first constrain the upper part of the retaining wall and the surface soil to prevent the surface soil from sliding to the side of the foundation pit during the excavation process, thus indirectly protecting the shallow foundation of the retaining wall.

[0087] 4) Separating the construction disturbance zone from the wall protection zone forms the first soil buffer barrier, weakening the stress release and soil deformation caused by the excavation of the foundation pit from being transmitted to the wall foundation, and forming a "double isolation defense line" with the isolation piles behind.

[0088] 5) Adapt to special working conditions where the existing wall is located above the extended base slab, and create safe working conditions. For working conditions where the wall is located above the extended base slab and it is not possible to first install deep isolation piles, stabilize the wall with retaining piles first, then excavate, cut the base slab, and construct channel steel isolation piles, providing a safe and orderly construction premise and achieving low-disturbance renovation construction.

[0089] Regarding the isolation barriers:

[0090] 1) Role: The second core water and soil barrier, working in coordination with the temporary support structure (the first line of protection).

[0091] 2) Vertically separate the soil on both sides to block deformation transmission: The channel steel is continuously arranged in opposite directions to form a complete vertical steel wall, which completely separates the original soil on the side of the wall from the disturbed soil of the foundation pit of the building to be modified; unloading, soil slippage, soil squeezing effect, stress release and other factors in the construction site cannot bypass the pile body to be transmitted to the shallow foundation of the wall, thus avoiding cracking, tilting and collapse of the wall from the root and making up for the shortcomings of the retaining piles which only provide surface protection.

[0092] 3) By penetrating the expanded base slab and creating a deep isolation channel, the wall rests on the expanded concrete base slab, making conventional isolation structures impossible to implement. Through static cutting of the base slab, anchor bolts with static pressure channel steel penetrate downwards through the slab, reaching the soil layer below, achieving full-height isolation from the base slab foundation to the deep bearing layer, filling the gap in the soil below the base slab. Isolation piles separate the expanded base slab from the existing building's main structure, reducing settlement resistance during the building's correction process.

[0093] 4) Share the deep lateral earth pressure and reduce the load of retaining piles. The retaining piles mainly protect the shallow soil above the main retaining wall; the isolation piles bear the lateral pressure of the deep soil below the bottom slab. The two form a double support, reducing the stress on a single structure and improving the safety reserve of the overall support system.

[0094] 5) Adaptable to low-disruption static construction, protecting existing structures. The anchor bolt static pressure process is impact-free and vibration-free, unlike drilling and hammer-driven pile construction; it will not cause vibration damage to old walls and existing extended base slabs, making it suitable for the renovation and upgrading of old buildings and sensitive scenarios involving surrounding structures. Furthermore, the retaining wall construction method of this invention differs substantially from existing retaining pile construction methods. It cannot be achieved through simple transplantation or conventional improvement of existing technologies, but requires creative effort from those skilled in the art. The specific differences are as follows:

[0095] 1) The integrated support system differs from traditional retaining pile construction, which relies solely on a single retaining pile and a simple capping beam, only serving the function of lateral soil retention in the foundation pit without a supporting soil isolation structure. Furthermore, in cases where the retaining wall sits above an expanded foundation slab, there are no dedicated isolation measures, and excavation disturbance is directly transmitted to the shallow foundation of the retaining wall. In this invention, the retaining piles are no longer used independently but are combined with channel steel isolation piles to form a dual protection system: retaining piles: the first line of defense, directly protecting the retaining wall; interlocking channel steel isolation piles: the second soil isolation barrier, completely separating the original soil of the retaining wall from the soil disturbed by construction excavation; the entire "retaining pile + concrete waler + channel steel isolation pile" composite support is an addition not present in traditional retaining pile technology.

[0096] 2) Differences in pre-construction logic and sequence of procedures: Traditional conventional enclosure construction sequence: If the enclosure wall is pressed on the outer expansion base plate, the traditional process can only excavate first. The outer expansion base plate blocks the construction of isolation piles. Without the pre-construction enclosure wall support during excavation, it is very easy to cause the enclosure wall to crack and tilt.

[0097] The differentiated construction sequence of this invention (first the retaining wall, then excavation, then isolation):

[0098] ① The timing of retaining pile construction should be prioritized: Before all earthwork excavation and bottom slab cutting operations, the retaining pile support on the side of the wall should be completed first. Traditional processes do not have the prior protection logic of "protecting the wall first and then excavating the soil".

[0099] ② There are specific limitations on the construction elevation of retaining piles: the top elevation of the retaining piles must be strictly aligned with the top elevation of the retaining wall foundation. Traditional retaining piles are designed only according to the foundation pit support elevation and do not match the retaining wall foundation.

[0100] ③ After the retaining piles are completed, a continuous reinforced concrete waler is forcibly added to connect the scattered retaining piles into a whole to wrap the foundation of the retaining wall. The traditional capping beam is only arranged along the edge of the foundation pit and does not fit into the foundation of the retaining wall for integrated reinforcement.

[0101] 3) A new procedure specifically for "the presence of an extended base slab under the wall": Traditional enclosure construction often uses a hydraulic breaker to violently remove the base slab when encountering obstacles such as an extended base slab, resulting in significant vibration and disturbance that directly damages the wall. The complete base slab treatment procedure of this invention is a completely new addition: earthwork excavation to the top surface of the extended base slab to create space for isolation pile operation; water drilling and static cutting of the foundation wing plate (low vibration, no impact); after cutting, static pressure channel steel interlocking isolation piles, pile section welding, and staggered joint arrangement to form a continuous water and soil barrier wall.

[0102] 4) Functional positioning differs from traditional retaining piles: they only serve the purpose of retaining soil during foundation pit excavation and do not take into account the special protection of the surrounding walls; the retaining piles of this invention: their primary function is to provide front-end protection for existing walls, and only secondarily to provide support. The design objectives and the objects of stress protection are completely different.

[0103] The enclosure construction method of the present invention can provide safe isolation and protection for the renovation and upgrading of existing buildings in high-density urban areas. It provides a feasible technical path for the protection of existing walls located above the outer base plate of existing buildings and the isolation construction of existing buildings. It reduces the impact on the surrounding environment of the construction area at a lower cost. The enclosure construction method takes into account both safety and economy and is feasible and operable.

[0104] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0105] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for constructing an enclosure for an existing wall, characterized in that, include: S1. Remove the ground level between the existing wall and the existing building to be renovated; S2. Construction of temporary support structures close to one side of the existing wall; S3. Excavate the earthwork between the temporary support structure and the existing building down to the surface of the outer base slab; S4. Divide the foundation wing plate of the outer expansion base plate at the predetermined position, and construct isolation piles at the divided position based on the static pressure of the anchor bolts. S5. Backfilling of earthwork between the temporary support structure and the existing building.

2. The construction method for enclosing an existing wall as described in claim 1, characterized in that, S2 includes the following steps: S21. Construct retaining piles close to one side of the wall, with the top elevation of the retaining piles being consistent with the top elevation of the existing wall foundation. S22. Construct walers at the top of the retaining piles and the foundation of the existing wall; the retaining piles and the walers at their tops together form a temporary support structure.

3. The construction method for enclosing an existing wall as described in claim 2, characterized in that, In S22, a concrete waler is constructed at the top of the retaining piles and the foundation top of the existing wall.

4. The construction method for enclosing an existing wall as described in claim 2, characterized in that, In S21, the construction of retaining piles along one side of the perimeter wall includes: Along the outer contour line of the retaining piles, water drills are used to drill circumferential holes to partially divide the foundation wing plate of the outward-expanding base plate along this contour. The retaining piles are vertically lowered into the hole until they reach the predetermined depth.

5. The construction method for enclosing an existing wall as described in claim 1, characterized in that, After the construction in S4 is completed, the bottom elevation of the isolation pile is lower than the bottom elevation of the temporary support structure after the construction in S2 is completed.

6. The construction method for enclosing an existing wall as described in any one of claims 1 to 5, characterized in that, In S4, the isolation pile is formed by two channel steels interlocking in opposite directions, welded in sections, and the joints of adjacent channel steels are staggered vertically.

7. The construction method for enclosing an existing wall as described in any one of claims 1 to 5, characterized in that, In S4, the isolation pile is located outside the temporary support structure and adjacent to the side of the existing building.

8. The construction method for enclosing an existing wall as described in any one of claims 1 to 5, characterized in that, In S4, the isolation pile extends down to the stable undisturbed soil layer below the bottom surface of the outward-expanding base plate.

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