Support design method and construction method suitable for tunnel turning section

Abstract

The application relates to a supporting design method and construction method suitable for a tunnel turning section. The supporting design method comprises the following steps: acquiring design parameters of a turning section of a tunnel; based on the design parameters of the turning section, determining a turning angle theta of a single construction cycle and a construction cycle number N; based on the design parameters of the turning section and the turning angle theta of the single construction cycle, calculating a pile length Xc and an inclination angle phic of an outer pile; based on the design parameters of the turning section and the turning angle theta of the single construction cycle, calculating a pile length Xd and an inclination angle phid of an inner pile; based on the pile length Xc and the inclination angle phic of the outer pile and the pile length Xd and the inclination angle phid of the inner pile, calculating a pile length Xi and an inclination angle phi of the remaining supporting piles between the outer pile and the inner pile. The number of required supporting piles in a supporting section is determined. The above supporting design method realizes parameterized construction of piles one by one, and can solve the problems of blank supporting and uneven lap joint of the supporting of the curve tunnel turning section.

Description

Technical Field

[0001] This application relates to the field of tunnel support construction technology, and in particular to a support design method and construction method adapted to tunnel curves. Background Technology

[0002] Horizontal high-pressure jet grouting piles are often used for the advanced reinforcement of tunnels in soft strata, water-rich sand layers, or overburden layers. By forming interlocking piles or curtains in front of the tunnel face, they improve the integrity and water-stopping properties of the strata outside the excavation outline.

[0003] Current tunnel construction methods are mostly designed for straight tunnel sections, typically arranging support piles with fixed outward angles, fixed pile lengths, and fixed circumferential spacing. However, when the tunnel enters a curve, the path lengths, offsets, and overlap relationships between adjacent construction cycles change along the inner and outer contour lines of the tunnel. If the same pile length and drilling direction as in straight sections are still used, problems such as insufficient coverage of the outer pile tails, excessively dense inner piles or localized cutting into preceding piles, uneven overlap between adjacent cycles, and difficulty in verifying the circumferential interlocking width can easily occur, thus creating weak support zones. Summary of the Invention

[0004] Therefore, it is necessary to provide a support design and construction method suitable for tunnel curves, addressing the issue of how to design and construct support for tunnel curves.

[0005] The specific plan is as follows:

[0006] In a first aspect, this application provides a support design method adapted to the curve section of a tunnel, comprising the following steps:

[0007] Obtain the design parameters for the tunnel's turning section;

[0008] Based on the design parameters of the turning section, determine the turning angle θ and the number of construction cycles N for a single construction cycle;

[0009] Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xc and the outward inclination angle φc of the outer pile.

[0010] Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xd and the outward inclination angle φd of the inner pile.

[0011] Based on the pile length Xc and outward inclination angle φc of the outer pile and the pile length Xd and outward inclination angle φd of the inner pile, calculate the pile length Xi and outward inclination angle φi of the remaining support piles located between the outer pile and the inner pile.

[0012] Determine the number of support piles required in the support section.

[0013] The technical solution will be further explained below:

[0014] In one embodiment, the design parameters for obtaining the turning section of the tunnel include the tunnel diameter D, the turning radius R of the turning section, the turning angle α of the turning section, the effective radius r of the high-pressure jet grouting pile, the maximum effective construction length Lmax, the minimum longitudinal overlap length Xj of adjacent construction cycles, the minimum circumferential interlocking width w, and the central angle γ corresponding to the support section.

[0015] In one embodiment, the step of determining the turning angle θ and the number of construction cycles N for a single construction cycle based on the design parameters of the turning segment includes:

[0016] Calculate the theoretical rotation angle θ1 for a single construction cycle, where the theoretical rotation angle θ1 for a single construction cycle satisfies:

[0017] tanθ1=(Lmax-Xj) / (R+D / 2);

[0018] Determine whether the outer piles meet the requirements for straight driving.

[0019] When (Lmax-Xj) / sinθ1-(R+D / 2)≥2r, the outer pile is determined to meet the straight driving condition. At this time, the rotation angle θ of a single construction cycle satisfies:

[0020] tanθ=tanθ1=(Lmax-Xj) / (R+D / 2);

[0021] When (Lmax-Xj) / sinθ1-(R+D / 2)<2r, the outer pile is determined not to meet the straight driving condition. At this time, the rotation angle θ of a single construction cycle satisfies:

[0022] ;

[0023] Determine the number of construction cycles N, where N is a positive integer obtained by rounding up the value of α / (θ-J1), and J1 is the compensation angle on the outer pile control circle, calculated from the longitudinal overlap length Xj. The compensation angle J1 satisfies:

[0024] .

[0025] In one embodiment, the number of construction cycles N is the smallest positive integer that satisfies the following conditions: the pile length Xc of the outer pile is not greater than Lmax, the pile length Xd of the outer pile is not greater than Lmax, the effective overlap length between adjacent construction cycles is not less than Xj, and the effective interlocking width of adjacent piles within the same support section is not less than w.

[0026] In one embodiment, the steps of calculating the pile length Xc and outward inclination angle φc of the outer pile based on the design parameters of the turning segment and the turning angle θ of a single construction cycle include:

[0027] When the outer pile meets the straight-drive condition, the pile length Xc and outward inclination angle φc of the outer pile satisfy the following:

[0028] φc=0°, .

[0029] In one embodiment, the steps of calculating the pile length Xc and outward inclination angle φc of the outer pile based on the design parameters of the turning segment and the turning angle θ of a single construction cycle include:

[0030] When the outer pile does not meet the straight-drive condition, the outward inclination angle φc satisfies:

[0031] φc = C1 - 90°, where C1 is the outer geometric auxiliary angle, satisfying:

[0032]

[0033] The pile length Xc of the outer pile satisfies:

[0034]

[0035]

[0036] .

[0037] In one embodiment, the steps of calculating the pile length Xd and the outward inclination angle φd of the inner pile based on the design parameters of the turning segment and the turning angle θ of a single construction cycle include:

[0038] Convert the longitudinal lap length Xj into the compensation angle J2 on the inner pile control circle:

[0039] ;

[0040] Determine whether a controlled trimming zone is set on the inner pile, wherein the controlled trimming zone is used to allow limited overlap or cutting between the current cycle drilling path and the end of the pile body in the previous cycle, and the limited overlap or cutting does not make the effective overlap length between adjacent construction cycles less than Xj.

[0041] When no controlled trimming zone is set, the pile length Xd and the outward inclination angle φd of the inner pile satisfy the following relationship:

[0042] ;

[0043] ;

[0044] φd = 90° - C2;

[0045] Let C2 be the inner geometric auxiliary angle, in which case C2 satisfies:

[0046] ;

[0047] When the inner pile is provided with a controlled trimming zone, the pile length Xd and the outward inclination angle φd of the inner pile satisfy the following relationship:

[0048] ;

[0049] φd = 90° - C2;

[0050] At this point, C2 satisfies:

[0051] .

[0052] In one embodiment, the step of calculating the pile length Xi and outward inclination angle φi of the remaining support piles located between the outer pile and the inner pile, based on the pile length Xc and outward inclination angle φc of the outer pile and the pile length Xd and outward inclination angle φd of the inner pile, includes:

[0053] Number all the support piles of the support section sequentially from the inside to the outside.

[0054] If there are n support piles in the support section, then the pile length Xi and outward inclination angle φi of the i-th support pile from the inside to the outside satisfy:

[0055] Xi=Xd+(i-1)(Xc-Xd) / (n-1), φi=φd-(i-1)(φd-φc) / (n-1);

[0056] Where i = 1, 2, ..., n.

[0057] In one embodiment, the step of determining the required number of support piles in the support section includes:

[0058] Calculate the radius Rd of the circle containing the tail of the inner pile and its corresponding interlocking central angle α. d :

[0059] , ;

[0060] Calculate the radius Rc of the circle containing the tail of the outer stake and its corresponding interlocking central angle α. c :

[0061] , ;

[0062] Compare the interlocking central angle αd of the inner stake with the interlocking central angle αc of the outer stake, and take the smaller one as αmin;

[0063] The number of support piles n required in the support section is: n = ceil(γ / αmin); where ceil() represents the rounding up function.

[0064] Secondly, this application also provides a support construction method adapted to the curve section of a tunnel, comprising the following steps:

[0065] Design each support pile according to the above support design method;

[0066] Drilling is performed based on the parameters of each support pile;

[0067] After drilling, high-pressure jet grouting is carried out to complete the construction of the support piles in one construction cycle;

[0068] Carry out the corresponding excavation and initial support;

[0069] Proceed to the next construction cycle until the support for the tunnel's turning section is completed.

[0070] In the aforementioned support design and construction method adapted to tunnel curves, the pile lengths and outward inclination angles of the inner and outer piles of the curve are first calculated using the design parameters of the tunnel curve. Based on this, the pile lengths and outward inclination angles of other support piles within the same support section are derived, and finally, the required number of support piles in the support section is calculated and determined. Compared with the traditional uniform parameter construction method, the support design method of this application fully considers the differences in pile lengths and outward inclination angles of all support piles within the support section, realizing parameterized construction for each pile. This can solve the problems of gaps and uneven overlaps in the support of curved tunnel curves. Simultaneously, key parameters such as the parameters of the inner piles, the parameters of the outer piles, and the turning angle θ of a single construction cycle are considered, enabling the design results to be directly used for on-site layout and drilling control. Attached Figure Description

[0071] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0072] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Furthermore, the accompanying drawings are not drawn to a 1:1 scale, and the relative dimensions of the various components are shown as examples only and not necessarily to scale. In the accompanying drawings:

[0074] Figure 1 This is a schematic diagram of the support structure for a tunnel bend section according to one embodiment.

[0075] Figure 2 This is a schematic diagram of the support structure for a single construction cycle of a tunnel bend, as shown in one embodiment.

[0076] Figure 3 This is a cross-sectional view of the support structure for a tunnel bend, according to one embodiment.

[0077] Figure 4 for Figure 2 The rear view of the support structure for a single construction cycle of the tunnel bend shown.

[0078] Figure 5 for Figure 2 The image shows a front view of the support structure for a single construction cycle of a tunnel bend.

[0079] Figure 6 This is a schematic diagram of the geometric relationship between a tunnel turning section, inner piles, and outer piles in one embodiment.

[0080] Figure 7 This is a schematic diagram illustrating the calculation of the pile length and outward inclination angle of the outer pile in one embodiment.

[0081] Figure 8 This is a schematic diagram illustrating the calculation of the pile length and outward inclination angle of an inner pile in one embodiment.

[0082] Explanation of reference numerals in the attached figures:

[0083] 11. Inner pile; 12. Outer pile. Detailed Implementation

[0084] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0085] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0086] Furthermore, where the terms "first" and "second" appear, these terms are 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 with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0087] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0088] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0089] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0090] To facilitate understanding of the technical solution of this application, a brief introduction to the support structure of the turning section of an arched tunnel will be given first, using the example of the support structure of the turning section. See [link to relevant documentation]. Figures 1 to 3 The support structure for the tunnel's turning section includes multiple support piles, which are sequentially installed along the tunnel's outer contour. Adjacent support piles along the tunnel's circumferential direction interlock, while adjacent support piles along the tunnel's axial direction overlap, thus forming a support shell that smoothly transitions with the tunnel's outer contour. For example, the support piles can be horizontal high-pressure jet grouting piles. During construction, holes are first drilled along the tunnel's outer contour, and then high-pressure jet grouting is applied into the holes to form the support piles. Understandably, due to the limited drilling and grouting depth of the equipment each time, a single construction operation can only complete the support pile construction within one circumferential cycle; multiple cycles are required to complete the entire tunnel's support structure.

[0091] As mentioned in the background section, current tunnel construction methods are mostly designed for straight tunnel sections, typically arranging support piles with fixed external angles, fixed pile lengths, and fixed circumferential spacing. However, when the tunnel line enters a curve, the path lengths, offsets, and overlap relationships between adjacent construction cycles change along the inner and outer contour lines of the tunnel. If the uniform pile length and drilling direction of the straight section are still used, problems such as insufficient coverage of the outer piles, overly dense inner piles or local cutting into the preceding piles, uneven overlap between adjacent cycles, and difficulty in verifying the circumferential interlocking width can easily occur, thus creating weak support zones.

[0092] Based on this, one embodiment of this application provides a support design method adapted to tunnel curves, the support design method comprising the following steps:

[0093] S110: Obtain the design parameters for the tunnel's turning section;

[0094] Specifically, such as Figure 4 , Figure 5 as well as Figure 6As shown, in some embodiments, the design parameters for the turning section include the tunnel diameter D, the turning radius R, the turning angle α, the effective radius r of the high-pressure jet grouting pile, the maximum effective construction length Lmax, the minimum longitudinal overlap length Xj of adjacent construction cycles, the minimum circumferential interlocking width w, and the central angle γ corresponding to the support section. Here, the effective radius r of the high-pressure jet grouting pile is also the radius of the constructed support pile; the maximum effective construction length Lmax is also the maximum pile length of the constructed support pile; the minimum longitudinal overlap length Xj of adjacent construction cycles is also the overlap length between two adjacent support piles along the tunnel axis; the minimum circumferential interlocking width w is also the interlocking width between adjacent support piles along the tunnel circumferentially. The central angle γ corresponding to the support section refers to the central angle corresponding to the envelope curve of the arched tunnel crown.

[0095] S120: Based on the design parameters of the turning section, determine the turning angle θ and the number of construction cycles N for a single construction cycle;

[0096] Specifically, such as Figure 6 As shown, a polar or rectangular coordinate system can be established in the plane with the center of the tunnel turning circle as the reference. Let R be the radius of the tunnel centerline; then the outer design control radius is denoted as Ro = R + D / 2 + e, and the inner design control radius is denoted as Ri = RD / 2 - e. Ro and Ri can be used to calculate the geometric boundaries of the outer long piles and the inner short piles, respectively; e is the maximum allowable linear over-excavation or profile offset. When the project requires control only based on the outward expansion of the pile core, e can be taken as the effective radius r of the high-pressure jet grouting pile or as the design allowable value.

[0097] like Figure 6 As shown, further, the turning angle θ of a single construction cycle refers to the central angle corresponding to the tunnel profile that can be covered by the support piles constructed in one cycle. Once the turning angle θ of a single construction cycle is determined, the number of construction cycles N = α / θ required to complete the support structure of the entire tunnel turning section can be obtained according to geometric relationships.

[0098] S130: Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xc and outward inclination angle φc of the outer pile 12.

[0099] like Figure 7 As shown, outer pile 12 refers to the support pile located on the outer vertical wall of the tunnel bend section. The outward inclination angle φc of outer pile 12 refers to the angle between outer pile 12 and the outer vertical wall of the tunnel.

[0100] S140: Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xd and the outward inclination angle φd of the inner pile 11;

[0101] like Figure 8As shown, inner pile 11 refers to the support pile located on the inner vertical wall of the tunnel bend section. The outward inclination angle φd of inner pile 11 refers to the angle between inner pile 11 and the inner vertical wall of the tunnel.

[0102] S150: Based on the pile length Xc and outward inclination angle φc of the outer pile 12 and the pile length Xd and outward inclination angle φd of the inner pile 11, calculate the pile length Xi and outward inclination angle φi of the remaining support piles located between the outer pile 12 and the inner pile 11.

[0103] like Figure 4 As shown, the remaining support piles located between the outer pile 12 and the inner pile 11 refer to the support piles located on the envelope curve of the arched tunnel, that is, the support piles within the range of the central angle γ corresponding to the support section.

[0104] S160: Determine the number n of support piles required in the support section.

[0105] Specifically, the number of support piles within the central angle γ range corresponding to the main support section can be determined based on the minimum circumferential interlocking width w.

[0106] The aforementioned support design method for tunnel curves utilizes the design parameters of the tunnel curve to calculate the pile lengths and outward inclination angles of the inner pile 11 and outer pile 12, respectively. Based on this, the pile lengths and outward inclination angles of other support piles within the same support section are derived, and the final number of support piles required in the support section is determined. Compared to traditional uniform parameter construction methods, the support design method of this application fully considers the differences in pile lengths and outward inclination angles of all support piles within the support section, achieving parameterized construction for each pile. This solves the problems of gaps and uneven overlaps in support during curve tunnel curves. Simultaneously considering key parameters such as the parameters of the inner pile 11, the parameters of the outer pile 12, and the turning angle θ of a single construction cycle, the design results can be directly used for on-site layout and drilling control.

[0107] See Figure 6 In some embodiments, step S120: Based on the design parameters of the turning segment, determining the turning angle θ and the number of construction cycles N for a single construction cycle specifically includes the following steps:

[0108] S121: Calculate the theoretical rotation angle θ1 for a single construction cycle, where the theoretical rotation angle θ1 for a single construction cycle satisfies:

[0109] tanθ1=(Lmax-Xj) / (R+D / 2);

[0110] Specifically, the theoretical angle θ1 for a single construction cycle is first determined by the maximum theoretical pile length Lmax of the support pile and the minimum overlap length of adjacent support piles.

[0111] S122: Determine whether the outer pile 12 meets the straight driving condition;

[0112] Specifically, for the outer control position of the turning section, the parameters of the outer pile 12 are calculated based on the outer design control radius Ro. If the turning angle θ of a single construction cycle is small, and the lateral deviation value Δo=Ro·(1-cosθ) generated by the outer control radius at this turning angle is not greater than the allowable coverage margin of the pile, then the outer long pile can be treated as an approximately straight driving condition; otherwise, it needs to be driven at an angle.

[0113] S123a: When (Lmax-Xj) / sinθ1-(R+D / 2)≥2r, the outer pile 12 is determined to meet the straight driving condition. At this time, the rotation angle θ of a single construction cycle satisfies:

[0114] tanθ=tanθ1=(Lmax-Xj) / (R+D / 2);

[0115] S1223b: When (Lmax-Xj) / sinθ1-(R+D / 2)<2r, it is determined that the outer pile 12 does not meet the straight driving condition. At this time, the rotation angle θ of a single construction cycle satisfies:

[0116] ;

[0117] S123: Determine the number of construction cycles N, where N is a positive integer obtained by rounding up the value of α / (θ-J1), and J1 is the compensation angle on the outer pile control circle obtained by converting the longitudinal overlap length Xj. The compensation angle J1 satisfies:

[0118] .

[0119] Specifically, the θ calculated above is often not an integer multiple of α. To reduce the pile length of horizontal jet grouting piles and shorten working hours, we can divide α into segments equal to the number of cycles N without changing the number of cycles. Rounding α / (θ-J1) up to the nearest integer gives N, and then recalibrating the rotation angle θ of a single construction cycle yields (θ-J1) = α / N. By optimizing the rotation angle θ and the number of construction cycles N for a single construction cycle, the number of construction cycles can be reduced while maintaining the maximum construction length and support continuity, which helps to reduce the construction period and cost.

[0120] Furthermore, the number of construction cycles N is the smallest positive integer that satisfies the following conditions: the pile length Xc of the outer pile 12 is not greater than Lmax; the pile length Xd of the outer pile 12 is not greater than Lmax; the effective overlap length between adjacent construction cycles is not less than Xj; and the effective interlocking width between adjacent piles within the same support section is not less than w. The reasonableness of the number of construction cycles N can be verified based on this number of cycles.

[0121] See Figure 7 In some embodiments, step S130: Based on the design parameters of the turning segment and the turning angle θ of a single construction cycle, calculate the pile length Xc and outward inclination angle φc of the outer pile 12, specifically including the following steps:

[0122] S131a: When the outer pile 12 meets the straight-drive condition, that is, (Lmax-Xj) / sinθ1-(R+D / 2)≥2r, the pile length Xc and outward inclination angle φc of the outer pile 12 satisfy:

[0123] φc=0°, .

[0124] S131b: When the outer pile 12 does not meet the straight driving condition, that is, when (Lmax-Xj) / sinθ1-(R+D / 2)≥2r, the outward inclination angle φc satisfies:

[0125] φc = C1 - 90°, where C1 is the outer geometric auxiliary angle, satisfying:

[0126]

[0127] At this time, the pile length Xc of the outer pile 12 satisfies:

[0128]

[0129]

[0130] .

[0131] See Figure 8 Step S140: Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xd and the outward inclination angle φd of the inner pile 11, specifically including the following steps:

[0132] S141: Convert the longitudinal lap length Xj into the compensation angle J2 on the inner pile control circle:

[0133] ;

[0134] S142: Determine whether a controlled trimming zone should be set up on the inner pile 11;

[0135] Specifically, a controlled trim zone is used to allow limited overlap or cutting between the current drilling path and the end of the pile in the previous cycle, provided that the limited overlap or cutting does not cause the effective overlap length between adjacent construction cycles to be less than Xj. In other words, a controlled trim zone can be set up provided that the effective overlap length is not less than Xj. The controlled trim zone is used to allow limited overlap or cutting between the current drilling path and the end of the pile in the previous cycle, rather than unrestrained destruction of the preceding support structure. The length or angle of the controlled trim zone should be less than a preset limit and should be checked using the safety margin of Xj. Understandably, a controlled trim zone may not be set up depending on the actual needs of the project.

[0136] S143a: When a controlled trimming zone is not set in the inner pile 11, the pile length Xd and the outward inclination angle φd of the inner pile 11 satisfy the following relationship:

[0137] ;

[0138] ;

[0139] φd = 90° - C2;

[0140] Let C2 be the inner geometric auxiliary angle, in which case C2 satisfies:

[0141] ;

[0142] S143b: When a controlled trimming zone is set for the inner pile 11, the pile length Xd and the outward inclination angle φd of the inner pile 11 satisfy the following relationship:

[0143] ;

[0144] φd = 90° - C2;

[0145] At this point, C2 satisfies:

[0146] .

[0147] See Figure 4 In some embodiments, step S150: calculating the pile length Xi and outward inclination angle φi of the remaining support piles located between the outer pile 12 and the inner pile 11 based on the pile length Xc and outward inclination angle φc of the outer pile 12 and the pile length Xd and outward inclination angle φd of the inner pile 11 includes:

[0148] S151: Number all the support piles of the support section sequentially from the inside to the outside.

[0149] Specifically, in this embodiment, all the support piles of the support section refer to the number of support piles within the central angle γ corresponding to the support section. They are numbered sequentially from the inside to the outside, with the first pile being the inner pile 11 and the last pile being the outer pile 12.

[0150] S151: If there are n support piles in the support section, then the pile length Xi and outward inclination angle φi of the i-th support pile from the inside to the outside satisfy:

[0151] Xi=Xd+(i-1)(Xc-Xd) / (n-1), φi=φd-(i-1)(φd-φc) / (n-1);

[0152] Where i = 1, 2, ..., n.

[0153] Specifically, after obtaining the parameters (Xd, φd) of the inner pile 11 and the parameters (Xc, φc) of the outer pile 12, the pile length Xi and outward inclination angle φi of the remaining support piles can be determined by linear interpolation or target curve interpolation according to the pile number on the support section. This ensures that the center point of the tail of each support pile is located within a continuous envelope curve or its allowable deviation zone, thereby enabling the support piles to form a support shell that smoothly transitions with the tunnel's curves in space.

[0154] It is worth noting that in a more precise implementation, the target points at the tail of each pile can be discretized on the target envelope curve corresponding to the support section first, and then Xi and φi can be directly calculated from the vector from the starting point of each borehole to the corresponding target point. This method can be used for tunnel sections with non-circular curves, transition curves, or composite curves, and will not be elaborated here.

[0155] See Figure 4 as well as Figure 5 In some embodiments, step S160: determining the number of support piles required in the support section includes:

[0156] S161: Calculate the radius Rd of the circle containing the tail of the inner stake 11 and its corresponding interlocking central angle α. d :

[0157] , ;

[0158] S162: Calculate the radius Rc of the circle containing the tail of the outer stake 12 and its corresponding interlocking central angle α. c :

[0159] , ;

[0160] S163: Compare the interlocking central angle αd of the inner post 11 with the interlocking central angle αc of the outer post 12, and take the smaller one as αmin;

[0161] S164: The required number of support piles n in the support section is: n = ceil(γ / αmin); where ceil() represents the rounding function. Specifically, the upper limit S of the center-to-center distance between adjacent support piles is determined based on the effective radius r of the high-pressure jet grouting pile and the minimum circumferential interlocking width w. max =2r-w. For the target envelope curve where the center point of the pile tail lies, calculate the chord length or arc length between adjacent target points at the pile tail, and ensure that it is no greater than S. max .

[0162] Furthermore, when using the circular arc approximation, it can be calculated as Δβmax = 2·arcsin(S max The maximum allowable central angle between adjacent piles is calculated using (2ρmin), where ρmin is the minimum equivalent radius of the target curve at the tail of the pile in that section. The number of support piles, n, should satisfy n≥ceil(γ / Δβmax)+1 (where γ is the central angle corresponding to the tunnel arch support range, and ceil() represents the rounding function). Simultaneously, if the design specifies a maximum pile center distance or support density requirement, the number of piles obtained according to this requirement should be compared with the number of piles obtained according to the interlocking requirement, and the larger value should be taken as the final number of piles.

[0163] By using the above dual-constraint verification, the problem of insufficient pile count caused by inferring only from the local interlocking angle can be avoided, and the calculation results can simultaneously meet the requirements of theoretical interlocking and engineering support density.

[0164] It is worth noting that the above calculation method for the number of support piles n only calculates the number of support piles within the range of the central angle γ corresponding to the support section. The number of outer piles can be calculated based on the height of the outer wall of the tunnel, the radius r of the outer pile, and the minimum circumferential interlocking width w. The method is relatively simple and will not be elaborated here. Similarly, the number of inner piles can be calculated based on the height of the inner wall of the tunnel, the radius r of the inner pile, and the minimum circumferential interlocking width w. This will not be elaborated here.

[0165] Based on the above calculations, the number of cycles N, the rotation angle θ of a single cycle, the parameters of the inner pile 11, the parameters of the outer pile 12, the parameters of each pile in the entire cross section, and the minimum number of piles n can form the same closed calculation chain, which can be directly used for subsequent construction layout and verification.

[0166] One embodiment of this application also provides a support construction method adapted to the curve section of a tunnel. The support construction method of one embodiment includes the following steps:

[0167] S210: Design each support pile according to the support design method of any of the above embodiments;

[0168] S220: Drilling is performed based on the parameters of each support pile;

[0169] S230: High-pressure jet grouting is performed after drilling to complete the construction of the support piles in one construction cycle;

[0170] S240: Perform excavation and initial support according to the corresponding advance;

[0171] S250: Proceed to the next construction cycle until the support for the tunnel bend is completed.

[0172] In the aforementioned support construction method adapted to tunnel curves, each support pile is first designed using the aforementioned support design method. In this method, the pile lengths and outward inclination angles of the inner pile 11 and outer pile 12 within the curve are calculated using the design parameters of the tunnel curve. Based on this, the pile lengths and outward inclination angles of other support piles within the same support section are derived, and finally, the required number of support piles in the support section is calculated and determined. Compared to the traditional uniform parameter construction method, the support design method of this application fully considers the differences in pile lengths and outward inclination angles of all support piles within the support section, achieving parameterized construction pile by pile. This solves the problems of gaps and uneven overlaps in the support of curved tunnel curves. Simultaneously, key parameters such as the parameters of the inner pile 11, the parameters of the outer pile 12, and the turning angle θ of a single construction cycle are considered, enabling the design results to be directly used for on-site layout and drilling control.

[0173] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0174] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A support design method adapted to tunnel curves, characterized in that, Includes the following steps: Obtain the design parameters for the tunnel's turning section; Based on the design parameters of the turning section, determine the turning angle θ and the number of construction cycles N for a single construction cycle; Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xc and the outward inclination angle φc of the outer pile. Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, calculate the pile length Xd and the outward inclination angle φd of the inner pile. Based on the pile length Xc and outward inclination angle φc of the outer pile and the pile length Xd and outward inclination angle φd of the inner pile, calculate the pile length Xi and outward inclination angle φi of the remaining support piles located between the outer pile and the inner pile. Determine the number of support piles required in the support section.

2. The support design method for tunnel curves according to claim 1, characterized in that, The design parameters for obtaining the turning section of the tunnel include the tunnel diameter D, the turning radius R of the turning section, the turning angle α of the turning section, the effective radius r of the high-pressure jet grouting pile, the maximum effective construction length Lmax, the minimum longitudinal overlap length Xj of adjacent construction cycles, the minimum circumferential interlocking width w, and the central angle γ corresponding to the support section.

3. The support design method for tunnel curves according to claim 2, characterized in that, The steps of determining the turning angle θ and the number of construction cycles N for a single construction cycle based on the design parameters of the turning segment include: Calculate the theoretical rotation angle θ1 for a single construction cycle, where the theoretical rotation angle θ1 for a single construction cycle satisfies: tanθ1=(Lmax-Xj) / (R+D / 2); Determine whether the outer piles meet the requirements for straight driving. When (Lmax-Xj) / sinθ1-(R+D / 2)≥2r, the outer pile is determined to meet the straight driving condition. At this time, the rotation angle θ of a single construction cycle satisfies: tanθ=tanθ1=(Lmax-Xj) / (R+D / 2); When (Lmax-Xj) / sinθ1-(R+D / 2)<2r, the outer pile is determined not to meet the straight driving condition. At this time, the rotation angle θ of a single construction cycle satisfies: ； Determine the number of construction cycles N, where N is a positive integer obtained by rounding up the value of α / (θ-J1), and J1 is the compensation angle on the outer pile control circle, calculated from the longitudinal overlap length Xj. The compensation angle J1 satisfies: 。 4. The support design method for tunnel curves according to claim 3, characterized in that, The number of construction cycles N is the smallest positive integer that satisfies the following conditions: the pile length Xc of the outer pile is not greater than Lmax, the pile length Xd of the outer pile is not greater than Lmax, the effective overlap length between adjacent construction cycles is not less than Xj, and the effective interlocking width of adjacent piles within the same support section is not less than w.

5. The support design method for tunnel curves according to claim 3, characterized in that, Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, the steps for calculating the pile length Xc and outward inclination angle φc of the outer pile include: When the outer pile meets the straight-drive condition, the pile length Xc and outward inclination angle φc of the outer pile satisfy the following: φc=0°, 。 6. The support design method for tunnel curves according to claim 3, characterized in that, Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, the steps for calculating the pile length Xc and outward inclination angle φc of the outer pile include: When the outer pile does not meet the straight-drive condition, the outward inclination angle φc satisfies: φc = C1 - 90°, where C1 is the outer geometric auxiliary angle, satisfying: The pile length Xc of the outer pile satisfies: 。 7. The support design method for tunnel curves according to claim 2, characterized in that, Based on the design parameters of the turning section and the turning angle θ of a single construction cycle, the steps for calculating the pile length Xd and the outward inclination angle φd of the inner pile include: Convert the longitudinal lap length Xj into the compensation angle J2 on the inner pile control circle: ； Determine whether a controlled trimming zone is set on the inner pile, wherein the controlled trimming zone is used to allow limited overlap or cutting between the current cycle drilling path and the end of the pile body in the previous cycle, and the limited overlap or cutting does not make the effective overlap length between adjacent construction cycles less than Xj; When no controlled trimming zone is set, the pile length Xd and the outward inclination angle φd of the inner pile satisfy the following relationship: ； ； φd = 90° - C2; Let C2 be the inner geometric auxiliary angle, in which case C2 satisfies: ； When the inner pile is provided with a controlled trimming zone, the pile length Xd and the outward inclination angle φd of the inner pile satisfy the following relationship: ； φd = 90° - C2; At this point, C2 satisfies: 。 8. The support design method for tunnel curves according to claim 7, characterized in that, The steps for calculating the pile length Xi and outward inclination angle φi of the remaining support piles located between the outer pile and the inner pile, based on the pile length Xc and outward inclination angle φc of the outer pile and the pile length Xd and outward inclination angle φd of the inner pile, include: Number all the support piles of the support section sequentially from the inside to the outside. If there are n support piles in the support section, then the pile length Xi and outward inclination angle φi of the i-th support pile from the inside to the outside satisfy: Xi=Xd+(i-1)(Xc-Xd) / (n-1), φi=φd-(i-1)(φd-φc) / (n-1); Where i = 1, 2, ..., n.

9. The support design method for tunnel curves according to claim 2, characterized in that, The steps for determining the number of support piles required in the support section include: Calculate the radius Rd of the circle containing the tail of the inner pile and its corresponding interlocking central angle α. d : ， ； Calculate the radius Rc of the circle containing the tail of the outer stake and its corresponding interlocking central angle α. c : ， ； Compare the interlocking central angle α of the inner stakes d The interlocking central angle α with the outer stake c Let the smaller one be denoted as α. min ; The number of support piles n required in the support section is: n = ceil(γ / α) min ); where ceil() represents the floor function.

10. A support construction method adapted to tunnel curves, characterized in that, Includes the following steps: Design each support pile according to the support design method according to any one of claims 1-9; Drilling is performed based on the parameters of each support pile; After drilling, high-pressure jet grouting is carried out to complete the construction of the support piles in one construction cycle; Carry out the corresponding excavation and initial support; Proceed to the next construction cycle until the support for the tunnel's turning section is completed.

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