A rigid-flexible combined freezing water-stopping structure for underground space considering construction errors and a method for determining construction parameters and a construction method thereof

Abstract

The present invention relates to an underground space rigid-flexible combined freezing water-stopping structure and a construction parameter determination method and a construction method thereof that take into account construction errors. The freezing water-stopping structure includes: a flexible freezing pipe, arranged on at least one side of the periphery of a foundation pit along a first direction, and the flexible freezing pipe extends obliquely in a curve to a certain depth below the base of the foundation pit; a rigid freezing pipe, arranged on at least two opposite sides of the periphery of the foundation pit along a second direction, and the rigid freezing pipe extends vertically in a straight line to a certain depth; and the flexible freezing pipe arranged along the first direction and the flexible freezing pipe or the rigid freezing pipe on the opposite side are staggered and crossed at a certain depth, and the frozen first frozen soil column intersects to form a frozen wall, which encloses the foundation pit from both sides and below the base; the second frozen soil column frozen by the rigid freezing pipe arranged along the second direction intersects to form a frozen wall, which encloses the foundation pit from both sides. The present invention can effectively isolate the hydraulic connection inside and outside the excavation area, achieve the purpose of effective water stopping, and ensure that the subsequent foundation pit excavation can proceed smoothly.

Description

Technical Field

[0001] The present invention relates to the technical field of water-stopping in urban underground space excavation construction, and specifically to an underground space rigid-flexible combined freezing water-stopping structure and a method for determining construction parameters and a construction method thereof that take construction errors into consideration. The present invention is particularly suitable for the technical field of freezing water-stopping during excavation of underground spaces with large stratum permeability coefficients and high groundwater levels. Background Art

[0002] With the continuous development of social economy, the continuous growth of population and the relative shrinkage of space, the development of urban underground space has become an important means and development trend for humans to expand their living space. With the increase of excavation depth, underground projects will encounter special environments such as deep depth, complex geological conditions, and underwater operations. Among them, the biggest impact on underground projects is the groundwater problem. Therefore, for the field of engineering construction, how to solve the groundwater problem under the premise of no or little precipitation is particularly important. Artificial freezing technology has become an effective way to reasonably solve the groundwater problem in urban underground space construction.

[0003] The traditional open-cut foundation pit freezing water-stopping structure can create conditions for foundation pit construction without or with little precipitation, but the open-cut foundation pit freezing water-stopping structure is highly dependent on the stratum. Whether there is a complete and continuous waterproof layer in the stratum determines whether the freezing project can be applied. The reason is that if a complete water-stopping structure cannot be formed, the frozen side wall (frozen wall) alone cannot isolate the hydraulic connection inside and outside the foundation pit.

[0004] Therefore, in the freezing construction before foundation pit excavation, how to form an effective freezing water-stopping structure to surround and isolate the foundation pit excavation range from all sides and the bottom without relying on the waterproof layer in the stratum is the key to the success of the freezing construction. The present invention conducts research on this. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art, propose a rigid-flexible freezing water-stopping structure suitable for underground space, and fully consider the influence of the construction error of directional drilling on the intersection of frozen soil columns, which can effectively form a frozen wall to isolate the hydraulic connection inside and outside the excavation area, achieve effective water-stopping purpose, and ensure that subsequent foundation pit excavation can proceed smoothly.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention provides an underground space rigid-flexible combined freezing water-stopping structure taking into account construction errors, which is formed by freezing of freezing pipes enclosed around the periphery of a foundation pit. The freezing water-stopping structure comprises:

[0008] A flexible freezing pipe is arranged on at least one side of the periphery of the foundation pit along a first direction, and the flexible freezing pipe extends obliquely to a certain depth below the foundation pit base in a curve with a certain curvature;

[0009] Rigid freezing pipes are arranged at least along the second direction on two opposite sides of the periphery of the foundation pit, and the rigid freezing pipes extend vertically in a straight line to a certain depth; and

[0010] The flexible freezing pipes arranged along the first direction are staggered and crossed with the flexible freezing pipes or rigid freezing pipes on the opposite side at a certain depth, and the frozen first frozen soil columns intersect to form a freezing wall, enclosing the foundation pit from both sides and below the base;

[0011] The second frozen soil columns frozen by the rigid freezing pipes arranged along the second direction intersect to form a freezing wall, enclosing the foundation pit from both sides.

[0012] In some embodiments, the flexible freezing pipes are arranged on opposite sides of the periphery of the foundation pit along a first direction, the rigid freezing pipes are arranged on opposite sides of the periphery of the foundation pit along a second direction, and the flexible freezing pipes and the flexible freezing pipes on the opposite sides are staggered and crossed at a certain depth below the base of the foundation pit.

[0013] In some embodiments, the flexible freezing pipe is arranged on one side of the periphery of the foundation pit along a first direction, the rigid freezing pipe is arranged on the other side of the periphery of the foundation pit along the first direction, and on two opposite sides of the periphery of the foundation pit along a second direction, and the flexible freezing pipe and the rigid freezing pipe on the opposite side are staggered and crossed at a certain depth.

[0014] In some embodiments, the flexible freezing pipe and the flexible freezing pipe on the opposite side are staggered and crossed at a certain depth below the base of the foundation pit to form a U-shaped or V-shaped freezing wall; the flexible freezing pipe and the rigid freezing pipe on the opposite side are staggered and crossed at a certain depth to form a semi-U-shaped or semi-V-shaped freezing wall.

[0015] In some embodiments, the flexible freezing pipe is arranged along the first direction on at least one side of the periphery of the foundation pit that is farther away from the enclosure.

[0016] In some embodiments, the flexible freezing pipe is a curved corrugated pipe, and the rigid freezing pipe is a straight seamless steel pipe.

[0017] In some embodiments, the flexible freezing pipe is constructed using a directional drilling rig.

[0018] A second aspect of the present invention provides a method for determining construction parameters of an underground space rigid-flexible combined freezing water-stopping structure taking into account construction errors, based on the aforementioned freezing water-stopping structure, comprising:

[0019] S10, taking the center of any flexible freezing pipe as the origin of the coordinate system, establishing a spherical coordinate system f(r, θ, φ);

[0020] S20, the spherical coordinate system and the three-dimensional rectangular coordinate system are converted at any position of the flexible freezing pipe through the three-dimensional rectangular coordinate system conversion formula:

[0021] (1)

[0022] In the formula, r is the straight-line distance from the starting point to the end point, that is, the chord length T, φ is the vertical inclination angle of the drill bit, and θ is the horizontal inclination angle;

[0023] S30, calculate the relationship between the chord length T and the arc length L of the flexible freezing pipe:

[0024] (2)

[0025] In the formula, Ψ is radians, is an intermediate quantity, L is a known parameter, T = 2R sin(180R / 2πL), and when it is substituted into the three-dimensional rectangular coordinate system (1), we can obtain:

[0026] (3)

[0027] S40, calculate the three-dimensional rectangular coordinate system equation of the flexible freezing pipe space curve:

[0028] F(x,y,z)= (4)

[0029] In the formula, R is the turning radius, which is the construction control quantity. The vertical inclination angle φ, the horizontal inclination angle θ, and the arc length L of the freezing pipe are all known quantities, which can be obtained through the data displayed on the drilling rig panel to obtain the three-dimensional coordinate position of a certain position of the flexible freezing pipe at a certain moment;

[0030] S50, calculate the curve equation of any point An: Assume that the curve equation between point A1 and starting point A0 is expressed by F A1 (x, y, z), then use F An (x, y, z) represents the curve equation at any point. By using formula (4), we can get F An (x, y, z) expression;

[0031] S60, calculate the curve equation of An when considering the error: Assuming that there is an error k in the drilling process of the drilling rig, A1 , F A2 , .......F An Perform fitting calculation to obtain the final F'(x, y, z), which is the flexible freezing pipe spatial curve considering construction errors;

[0032] S70, calculating subsequent flexible freezing pipe construction parameters based on the preceding flexible freezing pipe space curve.

[0033] In some embodiments, the calculation of subsequent flexible freezing pipe construction parameters includes:

[0034] Assume that the subsequent flexible freezing pipe space curve is G'(x, y, z), for any position An (xn, yn, zn), G' An Should meet:

[0035] G' An With F' An The distance is less than the diameter of the frozen soil column;

[0036] The distance between the starting drilling position of the flexible freezing pipe and the enclosure structure is M < the distance between the construction enclosure and the enclosure structure;

[0037] The Z value Z of G'(x, y, z) corresponding to the position M in the three-dimensional rectangular coordinate system where the enclosure structure is located （m） >N+(0.5~1m), N is the length of the enclosing structure.

[0038] A third aspect of the present invention provides a construction method for an underground space rigid-flexible combined freezing water-stopping structure taking into account construction errors, comprising:

[0039] S100, design the relevant parameters of the freezing wall according to the site conditions and freezing requirements;

[0040] S200, determining a combination arrangement of flexible freezing pipes and rigid freezing pipes according to site conditions, and arranging the flexible freezing pipes at a location where the excavation range of the foundation pit is relatively far from the enclosure range;

[0041] S300, uses geological drilling rigs to construct rigid freezing pipes, and uses directional drilling rigs to construct flexible freezing pipes;

[0042] S400, determining a spatial curve of any flexible freezing pipe by the aforementioned construction parameter determination method, and obtaining a spatial position of any position of the flexible freezing pipe taking into account construction errors, as a basis for subsequent flexible freezing pipe construction;

[0043] S500, determining a subsequent flexible freezing pipe space curve based on a preceding flexible freezing pipe space curve, and adjusting the directional drilling rig construction parameters accordingly, so that the position of the subsequent flexible freezing pipe is always at a distance from the preceding flexible freezing pipe space curve that meets the freezing design requirements.

[0044] The beneficial effects of the present invention compared to the prior art are as follows: the present invention proposes an underground space rigid-flexible combined freezing water-stopping structure and a construction parameter determination method and a construction method that take construction errors into consideration, adopts a freezing pipe arrangement that combines flexible freezing pipes with rigid freezing pipes to freeze groundwater to form a water-stopping curtain, and fully considers the construction error of each freezing pipe during the construction process. After the construction of the previous freezing pipe is completed, the construction angle and construction parameters of the subsequent freezing pipe are adjusted in time, thereby improving the accuracy of the freezing pipe construction, effectively solving the problem of frozen soil columns not intersecting or insufficient freezing wall thickness due to construction errors, and reducing engineering risks.

[0045] The flexible freezing pipe of the present invention adopts directional drilling rather than excavation technology to form holes for pipe installation, which is simple to operate, occupies less space, has a small operating space, requires fewer supporting measures, and has little environmental disturbance.

[0046] The flexible freezing pipe of the present invention adopts a hose (corrugated pipe), and the freezing hole arrangement trajectory has strong adaptability.

[0047] The flexible freezing pipes of the present invention are crossed to form a U-shaped freezing wall which can be formed in one step, thus avoiding the disadvantages of conventional side wall freezing + bottom freezing and having little influence on excavation support and structural construction.

[0048] The invention is green in construction and saves resources. A closed freezing wall outside the structure is easy to form, and the excavation range is not frozen, thereby reducing freezing energy consumption and difficulty of later excavation.

[0049] The present invention has a wide range of application scenarios and can be constructed both on the ground and in tunnels. It is adaptable to underground spaces of various structural forms and cross-sectional sizes, such as open excavation foundation pits and concealed excavation stations.

[0050] The present invention has significant environmental benefits, can replace precipitation, solve underwater construction problems, and is beneficial to water resource protection.

[0051] It should be understood that the contents described in the Summary of the Invention section are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easy to understand through the following description. In addition, the implementation of any embodiment of the present invention does not mean that multiple or all of the above-mentioned beneficial effects must be possessed or achieved at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0053] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment in size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0054] Figure 1 A plan view of freezing an open excavation pit according to some embodiments of the present invention is shown;

[0055] Figure 2 A schematic diagram of freezing and closing of an open excavation pit according to some embodiments of the present invention is shown;

[0056] Figure 3 Shows Figure 1 Schematic diagram of the unfrozen intersection of section 1-1;

[0057] Figure 4 Shows Figure 1 Schematic diagram of the freezing intersection of section 1-1;

[0058] Figure 5 Shows Figure 1 Schematic diagram of the unfrozen intersection of section 2-2;

[0059] Figure 6 Shows Figure 1 Schematic diagram of the freezing intersection of section 2-2;

[0060] Figure 7 A schematic diagram of an unfrozen intersection of section 1-1 of another embodiment is shown;

[0061] Figure 8 A schematic diagram of freezing the cross-circle in section 1-1 of another embodiment is shown;

[0062] Fig. 9 A schematic diagram of an unfrozen intersection of section 2-2 of another embodiment is shown;

[0063] Fig.10 A schematic diagram of freezing the intersection of section 2-2 of another embodiment is shown;

[0064] Fig.11 Shows Figure 1 Schematic diagram of the freezing intersection of section 3-3;

[0065] Fig.12 It shows a schematic diagram of an unfrozen intersection of the frozen 1-1 section of a dark excavation station according to some embodiments of the present invention;

[0066] Fig.13It shows a schematic diagram of freezing and crossing of a 1-1 section of a dark excavation station according to some embodiments of the present invention;

[0067] Fig.14 The schematic diagram of the plane showing the change of the intersection position of the frozen soil column caused by the construction error is shown;

[0068] Fig.15 A schematic diagram of the conversion of a spatial three-dimensional curve between a spherical coordinate system and a three-dimensional rectangular coordinate system according to some embodiments of the present invention is shown.

[0069] In the figure:

[0070] 1. Flexible freezing pipe; 11. First frozen soil column; 2. Rigid freezing pipe; 21. Second frozen soil column;

[0071] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with the embodiments and drawings. Here, the illustrative embodiments of the present invention and their description are used to explain the present invention, but are not intended to limit the present invention.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] It should be understood that the terms "include / comprise", "consist of..." or any other variations are intended to cover non-exclusive inclusion, so that a product, device, process or method that includes a series of elements includes not only those elements, but also may include other elements not explicitly listed when necessary, or also includes elements inherent to such product, device, process or method. In the absence of more restrictions, the elements defined by the sentence "include / comprise...", "consist of..." do not exclude the presence of other identical elements in the product, device, process or method that includes the elements.

[0075] It is also necessary to understand that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device, component or structure must have a specific direction, be constructed or operate in a specific direction, and should not be understood as a limitation on the present invention.

[0076] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0077] With the gradual development of science and technology, flexible freezing pipes have appeared in recent years. The change in material means that the path of the freezing pipes during construction is no longer limited to a straight line, but can form a curve with a certain curvature. In conjunction with directional drilling construction, the three-dimensional spatial position of the drill bit can be controlled and adjusted in real time.

[0078] Based on this, the present invention invents a rigid and flexible freezing water-stopping structure based on the flexible freezing pipe + directional drilling rig construction technology, and fully considers the freezing pipe construction error during specific construction to determine the construction parameters of any flexible freezing pipe and its subsequent flexible freezing pipes, to ensure that the frozen soil column formed by the freezing of each freezing pipe can be smoothly circled to form a complete and closed frozen wall, which effectively plays a role in waterproofing, and no longer depends on whether there is a waterproof layer in the stratum.

[0079] Glossary:

[0080] Underground space refers to the building space below the ground surface.

[0081] Staggered crossing means staggering a certain distance in space and crossing on the projection surface.

[0082] Intersection refers to the process in which the frozen soil column around the freezer gradually expands as the freezing time increases until adjacent frozen soil columns intersect.

[0083] The implementation of the present invention is described in detail below in conjunction with preferred embodiments.

[0084] like Figure 1 As shown, Figure 1The figure shows a common freezing and water-stopping scenario in underground space, i.e., the plan layout of the open excavation pit and the freezing and water-stopping structure. The figure takes the rectangular foundation pit commonly used in engineering as an example. The foundation pit retaining structure adopts commonly used retaining piles. The retaining piles are set along the edges of the foundation pit, leaving enough construction space (fat trough) away from the edge of the structure, and the solid structure is constructed on the inner side of the retaining piles.

[0085] The underground space rigid-flexible freezing water-stopping structure that takes construction errors into consideration provided by the present invention is formed by freezing of freezing pipes enclosed within the periphery of the foundation pit. The so-called rigid-flexible combination is a combination of flexible freezing pipes 1 and rigid freezing pipes 2 that are frozen to form frozen soil columns. The frozen soil columns intersect to form a closed freezing wall as a water-stopping structure, thereby isolating the hydraulic connection between the inside and outside of the foundation pit.

[0086] For details, please refer to the rigid-flexible combined freezing water-stopping structure of underground space Figure 1 , Figure 2 The flexible freezing pipe 1 is arranged on at least one side of the periphery of the foundation pit along a first direction, and the flexible freezing pipe 1 extends obliquely to a certain depth below the base of the foundation pit in a curve with a certain curvature. The rigid freezing pipe 2 is arranged on at least two opposite sides of the periphery of the foundation pit along a second direction, and the rigid freezing pipe 2 extends vertically to a certain depth in a straight line. The flexible freezing pipe 1 arranged along the first direction and the flexible freezing pipe 1 or the rigid freezing pipe 2 on the opposite side are staggered and crossed at a certain depth. The frozen first frozen soil column 11 intersects to form a frozen wall, which encloses the foundation pit from both sides and below the base; the second frozen soil column 21 frozen by the rigid freezing pipe 2 arranged along the second direction intersects to form a frozen wall, which encloses the foundation pit from both sides.

[0087] That is to say, the flexible freezing pipes 1 arranged along the first direction on one side and the flexible freezing pipes 1 or rigid freezing pipes 2 on the opposite side are staggered and cross-frozen to form a freezing wall that encloses the foundation pit from both sides and under the base, and the freezing wall formed by the freezing of the rigid freezing pipes 2 arranged along the second direction encloses the foundation pit from the other two sides. In this way, a fully enclosed enclosure is formed on all sides and the bottom of the foundation pit, effectively blocking the hydraulic connection between the inside and outside of the foundation pit. Moreover, since at least one side of the flexible freezing pipes 1 passes under the base of the foundation pit, a freezing wall is formed under the base, and effective freezing can be formed without relying on the impermeable layer in the stratum.

[0088] In a specific embodiment, if Figure 3-6As shown, the flexible freezing pipes 1 are arranged on two opposite sides of the periphery of the foundation pit along a first direction, and similarly, the rigid freezing pipes 2 are arranged on the other opposite sides of the periphery of the foundation pit along a second direction, and the flexible freezing pipes 1 on one side obliquely pass downwardly under the base of the foundation pit, and the flexible freezing pipes 1 on the other side also obliquely pass downwardly under the base of the foundation pit, and the two run towards each other, are nearly symmetrical, and cross at a certain depth below the base of the foundation pit (almost directly below), and the first frozen soil columns 11 formed by freezing intersect. In this arrangement, the first frozen soil columns 11 formed by the freezing of the flexible freezing pipes 1 on both sides intersect to form a U-shaped or V-shaped frozen wall, which is approximately U-shaped or V-shaped as shown in the figure, forming a frozen wall surrounding the foundation pit from two opposite sides of the foundation pit and below the base, and the rigid freezing pipes 2 form a frozen wall surrounding the foundation pit from the other opposite sides of the foundation pit, and are also frozen and intersected at the junction of the flexible freezing pipes 1 and the rigid freezing pipes 2 (as shown in the figure). Fig.11 ), thus forming a closed frozen wall surrounded on all sides.

[0089] In another specific embodiment, Figure 7-10 As shown, the flexible freezing pipe 1 is arranged only on one side of the periphery of the foundation pit along the first direction, while the rigid freezing pipe 2 is arranged on the other three sides of the periphery of the foundation pit, that is, the rigid freezing pipe 2 is arranged on the other side of the periphery of the foundation pit along the first direction, which is opposite to the flexible freezing pipe 1, and is arranged on the opposite sides of the periphery of the foundation pit along the second direction at the same time, and the flexible freezing pipe 1 still passes obliquely downward under the foundation pit base, passes down to the rigid freezing pipe 2 on the other side, and crosses with the rigid freezing pipe 2 at a certain depth, and the first frozen soil column 11 formed by freezing intersects with the second frozen soil column 21. Different from the previous embodiment, the flexible freezing pipe 1 on one side of the foundation pit passes from under the foundation pit base, and crosses with the rigid freezing pipe 2 at the rigid freezing pipe 2 on the other side, specifically near the bottom of the rigid freezing pipe 2, instead of crossing below the foundation pit base. In this arrangement, the first frozen soil column 11 formed by freezing of the flexible freezing pipe 1 on one side and the second frozen soil column 21 formed by freezing of the rigid freezing pipe 2 on the other side intersect to form a semi-U-shaped or semi-V-shaped frozen wall, which is approximately a semi-U-shaped or semi-V-shaped as shown in the figure. The frozen wall surrounds the foundation pit from two opposite sides of the foundation pit and below the base, and the rigid freezing pipe 2 forms a frozen wall around the foundation pit from the other two opposite sides of the foundation pit, and also freezes at the junction of the flexible freezing pipe 1 and the rigid freezing pipe 2 (such as Fig.11 ), thus forming a closed frozen wall surrounded on all sides.

[0090] The flexible freezing pipe 1 crosses to form a (semi) U-shaped or (semi) V-shaped freezing wall, which can be formed at one time, avoiding the disadvantages of conventional side wall freezing + bottom freezing, and has little impact on excavation support and structural construction. The closed freezing wall outside the structure is easy to form, and the excavation range is not frozen, which reduces the freezing energy consumption and the difficulty of later excavation, and is green construction and resource saving.

[0091] It should be noted that, due to the long construction period of flexible freezing pipes, high freezing costs, and high requirements for construction process control precision, the layout principle of flexible freezing pipes is to use as few as possible, so as to save construction costs and periods as much as possible under the premise of meeting freezing requirements. In addition, the flexible freezing pipes need to be arranged at a sufficient distance from the enclosure structure, which cannot be used in many construction sites if this distance is not available. Therefore, the latter implementation method is preferred under the premise of meeting freezing requirements.

[0092] In the present invention, considering that the flexible freezing pipe 1 is constructed obliquely, a wider construction area is required, so the flexible freezing pipe 1 should be arranged in an area at a greater distance from the enclosure outside the foundation pit.

[0093] In the present invention, the flexible freezing pipe 1 is constructed in a curved oblique direction, using a hose (corrugated pipe) and directional drilling technology, and the rigid freezing pipe 2 is constructed in a straight vertical direction, using a straight seamless steel pipe, and can be constructed using equipment such as a geological drill. The flexible freezing pipe 1 uses directional drilling rather than excavation technology to form holes and install pipes, which is simple to operate, occupies less space, has a small operating space, requires fewer supporting measures, and has less environmental disturbance. The hose (corrugated pipe) is used, the hose has good flexibility, and the freezing hole layout trajectory has strong adaptability.

[0094] Fig.12 , 13 Another common underground space freezing and water-stopping scenario is shown, namely the freezing and water-stopping structure of a concealed excavation station. The flexible freezing pipe 1 can be arranged on the opposite sides, and the first frozen soil column 11 formed by freezing intersects, or arranged on one side, and the first frozen soil column 11 formed by freezing intersects with the second frozen soil column 21. The specific arrangement method is the same as that of the open excavation foundation pit and will not be repeated.

[0095] Since the flexible freezing pipe 1 is not in a straight line, but in a curve with a certain curvature in cooperation with the directional drilling rig, although the directional drilling rig has navigation technology during construction, due to the invisibility of underground construction and the diversity, complexity and mutation of the stratum environment, the directional drilling rig is inevitably prone to construction errors when constructing curved flexible freezing pipes, and the errors are usually considerable, which can easily cause a large change in the final position of the flexible freezing pipe from its theoretical position, such as Fig.14 As shown in the figure, the position of the flexible freezing pipe deviates from its theoretical position by a distance of L*k, and this change will directly lead to the failure of the frozen soil column obtained by the freezing pipe to intersect at the predetermined position. Either the intersection cannot be formed, resulting in the non-closure of the frozen wall, or the actual intersection position changes. This will make it impossible to effectively form a freezing water-stopping structure to isolate the hydraulic connection inside and outside the excavation area, and the purpose of water-stopping cannot be achieved.

[0096] In view of this, the present invention provides a construction parameter determination method, or a calculation method, to calculate the construction parameters of flexible freezing pipes in a rigid-flexible combined freezing and water-stopping structure in an underground space, and fully consider the influence of construction errors. It can control the three-dimensional spatial position of the drill bit in real time during the construction of a directional drilling rig, ensure that the predetermined construction effect is achieved, and ensure the feasibility of the freezing plan.

[0097] The construction parameter determination method is as follows:

[0098] S10, firstly, taking the center of the flexible freezing pipe as the origin of the coordinate system, a spherical coordinate system f(r, θ, φ) is established;

[0099] like Fig.15 As shown, in the three-dimensional rectangular coordinate system, the center of the flexible freezing pipe is the origin of the coordinate system, the retaining pile is at a distance M from the starting drilling position of the flexible freezing pipe, the drill bit of the geological drill and the main machine display the vertical inclination angle φ, horizontal inclination angle θ, and arc length L of the flexible freezing pipe in real time, the distance between the drill bit position at any position and the starting point of the drilling is T (chord length), and L' is the minimum distance between the bottom of the retaining pile and the flexible freezing pipe to prevent the freezing pipe from hitting the retaining pile.

[0100] It should be noted that the origin of each flexible freezing pipe is a separate coordinate system, and the curve equation can be obtained under this coordinate system. When constructing the next flexible freezing pipe, the origin of the coordinate system is transferred to the origin of the next flexible freezing pipe, and the coordinate system changes over and over again.

[0101] S20, the spherical coordinate system and the three-dimensional rectangular coordinate system are converted at any position of the flexible freezing pipe through the three-dimensional rectangular coordinate system conversion formula:

[0102] (1)

[0103] In the formula, r is the straight-line distance from the starting point to the end point, that is, the chord length T, the vertical inclination angle φ, and the horizontal inclination angle θ are all known parameters;

[0104] S30, calculate the relationship between the chord length T and the arc length L of the flexible freezing pipe:

[0105] (2)

[0106] In the formula, Ψ is radians, is an intermediate quantity, L is a known parameter, T = 2R sin(180R / 2πL), and when it is substituted into the three-dimensional rectangular coordinate system (1), we can obtain:

[0107] (3)

[0108] S40, calculate the three-dimensional rectangular coordinate system equation of the flexible freezing pipe space curve:

[0109] F(x,y,z)= (4)

[0110] In the formula, the vertical inclination angle φ, the horizontal inclination angle θ, and the arc length L of the freezing pipe are all known quantities. R is the turning radius, which is the construction control quantity. At present, the minimum turning radius R of the drilling rig can reach 70m~120m. It can be obtained through the data displayed on the drilling rig panel to obtain the three-dimensional coordinate position of a certain position of the flexible freezing pipe at a certain moment;

[0111] S50, calculate the curve equation of any point An: Assume that the curve equation between point A1 and starting point A0 is expressed by F A1 (x, y, z), then use F An (x, y, z) represents the curve equation at any point. By using formula (4), we can get F An (x, y, z) expression;

[0112] S60, calculate the curve equation of An when considering the error: When the drilling rig construction does not produce any error, then F A1 (x, y, z) = F A2 (x, y, z) = ........ = F An (x, y, z) are all the same curve equation. However, in the actual construction process, due to geological conditions, construction errors, operational errors and other factors, there must be errors in the drilling process. Assuming that there is an error k in the drilling process of the drilling rig (in three-dimensional coordinates, any dimension may produce an error of k), the end point position error is directly related to the arc length L of the flexible freezing pipe and the construction accuracy k of the drilling rig, then the curve equation at any point will no longer be a fixed equation. Therefore, in order to improve the calculation accuracy, the least squares method or computer programming can be used to calculate F A1 , F A2 , .......F An A fitting calculation is performed to obtain the final F' (x, y, z), which is the spatial curve of the flexible freezing pipe taking into account the construction error. The spatial curve obtained by fitting has the smallest error with the actual curves and is the most representative.

[0113] After the spatial curve of the flexible freezing pipe in the three-dimensional rectangular coordinate system is determined, the position of any point can be known. To ensure that the distance between the position of the subsequent flexible freezing pipe and this spatial curve always maintains a fixed value (that is, the subsequent flexible freezing pipe is drilled in the predetermined direction and position), it is necessary to reset the drilling angle, offset, rotation radius, etc. of the subsequent flexible freezing pipe. That is, after obtaining a certain flexible freezing pipe spatial curve that takes into account the construction error, it can be used as a basis to continue to calculate the subsequent flexible freezing pipe construction parameters, namely:

[0114] S70, calculating subsequent flexible freezing pipe construction parameters based on the preceding flexible freezing pipe space curve.

[0115] Specifically, assuming that the subsequent flexible freezing pipe space curve is G'(x, y, z), for any position An (xn, yn, zn), G' An Should meet:

[0116] G' An With F' An The distance is less than the diameter of the frozen soil column, usually 2 / 3 of the thickness of the frozen wall;

[0117] The distance between the starting drilling position of the flexible freezing pipe and the enclosure structure is M < the distance between the construction enclosure and the enclosure structure;

[0118] The Z value of G' (x, y, z) corresponding to the position M of the enclosure structure in the three-dimensional rectangular coordinate system should have a certain safety distance from the length N of the enclosure structure. （m） >N+(0.5~1m), that is, a safety distance of 0.5~1m should be maintained, and N is the length of the retaining structure, that is, the length of the retaining piles.

[0119] Through the above calculation method, the construction error is fully taken into account. For any flexible freezing pipe, its spatial curve taking into account the construction error is obtained. With the help of this spatial curve, the construction parameters of the directional drilling rig can be adjusted in real time, and the subsequent construction can be guided in real time to ensure the smooth intersection of each frozen soil column and form a complete frozen wall, which effectively plays a role in waterproofing.

[0120] Through the above calculation iterations, the subsequent flexible freezing pipes can be adjusted in time based on the actual construction space position of the previous flexible freezing pipes, so as to realize the refined construction of each flexible freezing pipe, ensure the intersection of the frozen soil columns, form a complete and closed frozen wall, and isolate the hydraulic connection inside and outside the foundation pit.

[0121] The purpose of the present invention can be achieved by combining the following measures:

[0122] 1. The construction of retaining piles adopts ordinary pile foundation construction technology, and the retaining structure is not limited to retaining piles, but can be retaining forms such as ground-connected walls and SMW piles. The freezing system is mainly used for water stopping, and the retaining system is mainly used to bear external loads;

[0123] 2. After the construction of the retaining structure is completed, the important parameters such as the thickness of the frozen wall, average temperature, spacing, etc. are determined according to the shape of the foundation pit, site size, geological characteristics, groundwater flow rate, temperature and other conditions. Figure 1 , Figure 2 ;

[0124] 3. According to the distance between the enclosure structure and the construction red line, you can choose a combination of flexible freezing pipes on both sides + rigid freezing pipes on both sides. Figure 3-6 As shown, you can also choose a single-side flexible freezing pipe + three-side rigid freezing pipe combination mode. Figure 7-10 As shown in the figure, usually the area where the foundation pit excavation is far from the enclosure is selected as the area for arranging flexible freezing pipes. Figure 1~Figure 2 ;

[0125] 4. After the construction of the retaining structure is completed, according to the site conditions and freezing requirements, such as the shape of the foundation pit, the size of the site, geological characteristics, groundwater velocity, temperature and other conditions, determine the important parameters of freezing, that is, design the relevant parameters of the freezing wall, including the thickness of the freezing wall, the average temperature of the freezing wall, the spacing of the freezing pipes, the temperature of the refrigerant, etc.;

[0126] 5. During the construction of rigid freezing pipes and flexible freezing pipes, the construction error is fully considered, the space curve of the flexible freezing pipe is determined, the construction parameters of the flexible freezing pipe considering the construction error are obtained, and the directional drilling construction of the flexible freezing pipe is guided based on the construction parameters, mainly:

[0127] Firstly, the spatial curve of the flexible freezing pipe is determined, and the spatial position of any position of the flexible freezing pipe considering the construction error is obtained, which serves as the basis for the subsequent construction of the flexible freezing pipe.

[0128] Then, based on the previous flexible freezing pipe space curve, the subsequent flexible freezing pipe space curve is determined, and the directional drilling rig construction parameters such as drilling position, drilling angle, deflection angle, turning radius, etc. are adjusted accordingly, so that the position of the subsequent flexible freezing pipe can always meet the freezing design requirements with the distance from the previous flexible freezing pipe space curve. Specifically, the two can always maintain a fixed value, that is, the subsequent flexible freezing pipe is drilled in the predetermined direction and position to ensure that each flexible freezing pipe can be frozen smoothly.

[0129] The underground space rigid-flexible freezing water-stopping structure and construction method provided by the present invention adopt a freezing pipe arrangement form combining flexible freezing pipes with rigid freezing pipes to freeze groundwater to form a water-stopping curtain, and fully consider the construction error of each freezing pipe during the construction process. After the construction of the subsequent freezing pipes is completed, the construction angle and construction parameters of the freezing pipes are adjusted in time, thereby improving the accuracy of the freezing pipe construction, effectively solving the problem of frozen soil columns not intersecting or insufficient freezing wall thickness due to construction errors, and reducing engineering risks.

[0130] The present invention is suitable for groundwater freezing and water-stopping construction in various underground spaces, such as open excavation, large foundation pit freezing and water-stopping construction, concealed excavation station freezing and water-stopping construction, etc. The structure and construction method do not pump groundwater, do not change the groundwater migration path, and do not pollute the groundwater environment. It is especially suitable for large cities, densely built-up areas, and areas with large stratum permeability coefficients. The freezing pipes are all constructed on the surface and are hidden in the distribution pipe trench after construction, without occupying surface space.

[0131] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0132] Although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the present invention. Certain features described in the context of separate embodiments may also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable sub-combination.

Claims

1. A method for determining construction parameters of a rigid-flexible combined freezing water-stopping structure for an underground space taking into account construction errors, wherein the freezing water-stopping structure is formed by freezing a freezing pipe enclosed around a foundation pit, comprising: A flexible freezing pipe is arranged on at least one side of the periphery of the foundation pit along a first direction, and the flexible freezing pipe extends obliquely to a certain depth below the foundation pit base in a curve with a certain curvature; Rigid freezing pipes are arranged at least along the second direction on two opposite sides of the periphery of the foundation pit, and the rigid freezing pipes extend vertically in a straight line to a certain depth; and The flexible freezing pipes arranged along the first direction are staggered and crossed with the flexible freezing pipes or rigid freezing pipes on the opposite side at a certain depth, and the frozen first frozen soil columns intersect to form a freezing wall, enclosing the foundation pit from both sides and below the base; The second frozen soil columns frozen by the rigid freezing pipes arranged along the second direction intersect to form a frozen wall, enclosing the foundation pit from both sides; Characterized in that the construction parameter determination method comprises: S10, taking the center of any flexible freezing pipe as the origin of the coordinate system, establishing a spherical coordinate system f(r, θ, φ); S20, the spherical coordinate system and the three-dimensional rectangular coordinate system are converted at any position of the flexible freezing pipe through the three-dimensional rectangular coordinate system conversion formula: （1） In the formula, r is the straight-line distance from the starting point to the end point, that is, the chord length T, φ is the vertical inclination angle of the drill bit, and θ is the horizontal inclination angle; S30, calculate the relationship between the chord length T and the arc length L of the flexible freezing pipe: （2） In the formula, Ψ is radians, is an intermediate quantity, L is a known parameter, T = 2R sin(180R / 2πL), and when it is substituted into the three-dimensional rectangular coordinate system (1), we can obtain: （3） S40, calculate the three-dimensional rectangular coordinate system equation of the flexible freezing pipe space curve: F(x,y,z)= (4) In the formula, R is the turning radius, which is the construction control quantity. The vertical inclination angle φ, the horizontal inclination angle θ, and the arc length L of the freezing pipe are all known quantities, which can be obtained through the data displayed on the drilling rig panel to obtain the three-dimensional coordinate position of a certain position of the flexible freezing pipe at a certain moment; S50, calculate the curve equation of any point An: Assume that the curve equation between point A1 and starting point A0 is expressed by F A1 (x, y, z), then use F An (x, y, z) represents the curve equation at any point. F can be obtained by equation (4). An (x, y, z) expression; S60, calculate the curve equation of An when considering the error: Assuming that there is an error k in the drilling process of the drilling rig, A1 , F A2 , .......F An Perform fitting calculation to obtain the final F'(x, y, z), which is the flexible freezing pipe spatial curve considering construction errors; S70, calculating subsequent flexible freezing pipe construction parameters based on the preceding flexible freezing pipe space curve.

2. The method for determining construction parameters according to claim 1, characterized in that: The flexible freezing pipes are arranged on opposite sides of the periphery of the foundation pit along a first direction, the rigid freezing pipes are arranged on opposite sides of the periphery of the foundation pit along a second direction, and the flexible freezing pipes and the flexible freezing pipes on the opposite sides are staggered and crossed at a certain depth below the base of the foundation pit.

3. The method for determining construction parameters according to claim 1, characterized in that: The flexible freezing pipe is arranged on one side of the periphery of the foundation pit along the first direction, the rigid freezing pipe is arranged on the other side of the periphery of the foundation pit along the first direction, and on two opposite sides of the periphery of the foundation pit along the second direction, and the flexible freezing pipe and the rigid freezing pipe on the opposite side are staggered and crossed at a certain depth.

4. The method for determining construction parameters according to claim 2 or 3, characterized in that: The flexible freezing pipe and the flexible freezing pipe on the opposite side are staggered and crossed at a certain depth below the base of the foundation pit to form a U-shaped or V-shaped freezing wall; the flexible freezing pipe and the rigid freezing pipe on the opposite side are staggered and crossed at a certain depth to form a semi-U-shaped or semi-V-shaped freezing wall.

5. The method for determining construction parameters according to any one of claims 1 to 3, characterized in that: The flexible freezing pipe is arranged along the first direction on at least one side of the periphery of the foundation pit which is farther away from the enclosure.

6. The method for determining construction parameters according to any one of claims 1 to 3, characterized in that: The flexible freezing pipe adopts a curved corrugated pipe, and the rigid freezing pipe adopts a straight seamless steel pipe.

7. The method for determining construction parameters according to any one of claims 1 to 3, characterized in that: The flexible freezing pipe is constructed by using a directional drilling rig.

8. The method for determining construction parameters according to claim 1, characterized in that: The calculation of subsequent flexible freezing pipe construction parameters includes: Assume that the subsequent flexible freezing pipe space curve is G'(x, y, z), for any position An (xn, yn, zn), G' An Should meet: G' An With F' An The distance is less than the diameter of the frozen soil column; The distance between the starting drilling position of the flexible freezing pipe and the enclosure structure is M < the distance between the construction enclosure and the enclosure structure; The Z value Z of G'(x, y, z) corresponding to the position M in the three-dimensional rectangular coordinate system where the enclosure structure is located （m） >N+(0.5~1m), N is the length of the enclosing structure.

9. A construction method based on the construction parameter determination method according to any one of claims 1 to 8, characterized in that: include: S100, design the relevant parameters of the freezing wall according to the site conditions and freezing requirements; S200, determining a combination arrangement of flexible freezing pipes and rigid freezing pipes according to site conditions, and arranging the flexible freezing pipes at a location where the excavation range of the foundation pit is relatively far from the enclosure range; S300, uses geological drilling rigs to construct rigid freezing pipes, and uses directional drilling rigs to construct flexible freezing pipes; S400, determining a spatial curve of any flexible freezing pipe using the construction parameter determination method described in any one of claims 1 to 8, and obtaining a spatial position of any position of the flexible freezing pipe taking into account construction errors, as a basis for subsequent flexible freezing pipe construction; S500, determining a subsequent flexible freezing pipe space curve based on a preceding flexible freezing pipe space curve, and adjusting the directional drilling rig construction parameters accordingly, so that the position of the subsequent flexible freezing pipe is always at a distance from the preceding flexible freezing pipe space curve that meets the freezing design requirements.

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