Prestress optimization method for multiple rows of anchor cables

Abstract

The invention relates to a multi-row anchor cable pre-stress optimization method, which belongs to the technical field of anchor cable pre-stress optimization, and comprises the following steps: S1, constructing a cast-in-situ bored pile supporting structure model comprising a plurality of rows of anchor cables in numerical simulation software; s2, the standard prestress of all the anchor cables is determined in a unified mode; s3, according to the reference prestress, the corresponding optimal prestress of each row of anchor cables is obtained, and according to the corresponding optimal prestress of each row of anchor cables, the optimal bending moment of the cast-in-situ bored pile is obtained; and S4, the optimal prestress of each row of anchor cables is subjected to secondary adjustment, and the final prestress of all the anchor cables is obtained. According to the method, the optimal prestress of each row of anchor cables can be accurately determined, the stability of a cast-in-situ bored pile supporting structure can be effectively improved, and the practical value is high.

Description

Technical Field

[0001] The invention belongs to the technical field of anchor cable prestress optimization, and in particular belongs to a method for optimizing the prestress of multiple-row anchor cables. Background Art

[0002] In existing geotechnical engineering practices, bored cast-in-place pile support structures are often used in scenarios such as slope stabilization and deep foundation pit support. As a common bored cast-in-place pile reinforcement method, the prestress of anchor cables directly affects the performance of the entire support structure.

[0003] Traditional prestressing methods often use empirical estimates and lack a comprehensive optimization solution for multi-row anchor systems. Empirical estimates can lead to problems such as uneven prestressing and poor support effects. Summary of the invention

[0004] The multi-row anchor cable prestress optimization method of the present invention can comprehensively optimize the prestress of the multi-row anchor cable system.

[0005] A method for optimizing prestressing of multiple rows of anchor cables of the present invention comprises the following steps:

[0006] S1: Construct a bored pile support structure model containing multiple rows of anchor cables in numerical simulation software;

[0007] S2: Uniformly determine the reference prestress of all anchor cables;

[0008] S3: According to the reference prestress, the corresponding optimal prestress of each row of anchor cables is obtained respectively, and according to the optimal prestress corresponding to each row of anchor cables, the first optimal bending moment peak value generated by the bored pile is obtained;

[0009] S4: Secondary adjustment of the optimal prestress of each row of anchor cables to obtain the second optimal bending moment peak value generated by the bored piles;

[0010] Determine whether the second optimal bending moment peak value meets the set standard, and if so, obtain the prestress of each row of anchor cables corresponding to the second optimal bending moment peak value;

[0011] If it does not meet the requirements, the optimal prestress in S3 is adjusted three times to obtain the third optimal bending moment peak value generated by the bored pile; and whether the third optimal bending moment peak value meets the set standard is determined again.

[0012] And so on…

[0013] Assuming that the Vth optimal bending moment peak value meets the standard, the prestress of each row of anchor cables corresponding to the Vth optimal bending moment peak value is obtained.

[0014] Further, step S2 includes the following steps:

[0015] S2.1: In the numerical simulation software, all anchor cables are prestressed with P m , m∈{1,2,……,n}, prestress is applied to all anchor cables n times, and the prestress applied to all anchor cables in each prestress application is the same;

[0016] As the number of times the prestress is applied increases, m increases accordingly, and the applied prestress P m It also increases accordingly; the difference between two adjacent prestressing forces:

[0017] S2.2: When all anchor cables are subjected to a certain prestress P m When the external load and anchor cable force are combined, the bored pile will produce a corresponding peak bending moment.

[0018] The peak bending moment is expressed as follows: when all anchor cables are subjected to the same or different prestress, different bending moments will be generated at each cross section of the bored pile. Assuming there are G cross sections in total, the bored pile will generate G bending moments. The moment with the largest absolute value among the G bending moments is the peak bending moment.

[0019] When all anchor cables are subjected to n prestress P m When the prestress P of each anchor cable m Different, so the bored piles produce different peak moments; all anchor cables are added with n prestress P m , the bored pile generates n bending moment peaks; select the smallest bending moment peak among the n bending moment peaks, denoted as M o,min ;

[0020] S2.3: According to the numerical simulation software, M o,min Input into the numerical simulation software to obtain the prestress P at this time o,min ; P o,min The same prestress is used as the base prestress for all anchor cables.

[0021] Further, step S3 includes the following steps:

[0022] S3.1: Number each row of anchor cables from top to bottom, denoted by k, k∈{1,2,3,4,5};

[0023] S3.2: Apply prestress P to the anchor cable with number k = 1 j , j∈{3,4,……,n}, prestress P j As j increases, the difference in adjacent prestressing forces increases. The anchor cable with number k=1 is prestressed n-2 times. Each time the anchor cable with number k=1 is prestressed, the anchor cables with other numbers maintain the reference prestress P o,min ;

[0024] The anchor cable with number k=1 is prestressed P j , other anchor cables maintain the reference prestress P o,min When the peak bending moment of the bored pile is obtained, the anchor cable numbered k=1 is applied with n-2 prestress P j , bored piles produce a total of n-2 bending moment peaks;

[0025] Apply prestress P to the anchor cable numbered k=2 j , j∈{3,4,……,n}, prestress P j As j increases, the difference in adjacent prestressing forces increases. ; The anchor cable with number k=2 is prestressed n-2 times. Each time the anchor cable with k=2 is prestressed, the anchor cables with other numbers maintain the reference prestress P o,min ;

[0026] The anchor cable with number k=2 is prestressed P j , other anchor cables maintain the reference prestress P o,min When the peak bending moment of bored pile is obtained, the anchor cable with number k=2 is applied with n-2 prestress P j , bored piles produce a total of n-2 bending moment peaks;

[0027] And so on…

[0028] S3.3: Apply prestress P to the anchor cable with number k = 1 j When , compare the n-2 bending moment peaks and select the smallest bending moment peak among the n-2 bending moment peaks; record it as

[0029] The anchor cable with number k=2 is prestressed P j When , the bored pile generates n-2 bending moment peaks in total. Compare the n-2 bending moment peaks and select the smallest bending moment peak among the n-2 bending moment peaks; record it as

[0030] And so on…

[0031] The minimum bending moment peak values ​​of anchor cables numbered 1 to 5 are recorded as follows:

[0032]

[0033] S3.4: Enter the values ​​in the numerical simulation software Each time the above-mentioned minimum bending moment peak is input into the numerical simulation software, an optimal prestress is correspondingly outputted in the numerical simulation software;

[0034] Assume that the numerical simulation software inputs When the numerical simulation software outputs the corresponding optimal prestress

[0035] Input into numerical simulation software When the numerical simulation software outputs the corresponding optimal prestress

[0036] And so on…

[0037] The optimal prestress outputted for each of the above-mentioned minimum bending moment peaks is:

[0038]

[0039] S3.5: Input all the optimal prestresses in S3.4 into the numerical simulation software simultaneously. Corresponding to the optimal prestress applied by anchor cable No. 1, This corresponds to the optimal prestress applied to the anchor cable numbered 2; and so on..., all anchor cables with corresponding numbers are corresponding to the optimal prestress applied;

[0040] The peak bending moment generated by the bored pile at this time is obtained and set as the first optimal bending moment peak value, recorded as t=1.

[0041] Further, step S4 includes the following steps:

[0042] S4.1: Set t=1, L=2;

[0043] S4.2: Prestress the anchor cable numbered k=1. L∈{2,3,4,5,…,}, t∈{1,2,3,4,5,…,}; Assume that a total of u prestressing forces are applied, and u changes with the values ​​of L and t; the anchor cables with other numbers maintain the optimal prestressing force;

[0044] The anchor cable with number k=1 is prestressed P y When the anchor cables with other numbers maintain the optimal prestress, the anchor cable with number k=1 is given the prestress P y The peak bending moment generated by the bored pile at the time is u times; a total of u prestressing forces are applied, and the bored pile generates a total of u times of bending moment peaks, which are recorded as

[0045] Apply prestress to the anchor cable numbered k=2 L∈{2,3,4,5,…,}, t∈{1,2,3,4,5,…,}; Assume that a total of u prestressing forces are applied, and u changes with the values ​​of L and t; the anchor cables with other numbers maintain the optimal prestressing force;

[0046] The anchor cable with number k=2 is prestressed P y When , the bored pile produces the corresponding bending moment peak; a total of u prestresses are applied, and a total of u bending moment peaks are produced by the bored pile, which are recorded as ……、

[0047]

[0048] And so on…

[0049] S4.3: Select the bending moment peak with the smallest absolute value among all the bending moment peaks generated by bored piles in S4.2 and set it as the t+1th optimal bending moment peak, denoted as and obtain The final prestress of each corresponding numbered anchor cable;

[0050] S4.4: Calculate the optimum bending moment ratio using the formula:

[0051]

[0052] S4.5: If ε<5%, it meets the set parameter standard and outputs the value in S4.3. The final prestress of each corresponding numbered anchor cable;

[0053] Otherwise, it does not meet the set parameter standard; if it does not meet the set parameter standard, then simultaneously substitute t=t+1 and L=L+1 into S4.2-S4.5 for the cycle; assuming: Then the final prestress of each numbered anchor cable under the Vth optimal bending moment peak value is output.

[0054] Beneficial effects:

[0055] This scheme accurately determines the optimal prestress of each row of anchor cables, which can effectively improve the stability of the bored pile support structure and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a flow chart of this optimization method.

[0057] Figure 2 This is the bored cast-in-place pile support structure model constructed in Example 1.

[0058] Figure 3 Displacement cloud diagram and bending moment diagram of bored piles when a benchmark prestress of 400kN is uniformly applied to all anchor cables. Figure 3 a is the displacement cloud diagram of bored pile; Figure 3 b is the bending moment diagram of bored cast-in-place piles.

[0059] Figure 4Displacement nephogram and bending moment diagram of bored cast-in-place piles under optimal prestress. Figure 4 a is the displacement cloud diagram of bored pile under optimal prestress, Figure 4 b is the bending moment diagram under optimal prestress.

[0060] Figure 5 Displacement cloud diagram and bending moment diagram of bored cast-in-place piles when final prestress is applied to anchor cables of different numbers. Figure 5 a is the displacement cloud diagram of bored piles when the final prestress is applied to the anchor cables of each number; Figure 5 b is the bending moment diagram of bored piles when the final prestress is applied to the anchor cables of each number. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] See Figure 1 , a method for optimizing the prestressing of multiple rows of anchor cables, comprising the following steps:

[0063] S1: In the numerical simulation software, a bored pile support structure model containing multiple rows of anchor cables is constructed.

[0064] In this embodiment, a bored pile support structure model including five rows of anchor cables is constructed, and each row of anchor cables is supported at a different height of the model. Figure 2 This is the model of the five-row bored pile support structure constructed in S1.

[0065] S2: Uniformly determine the reference prestress of each row of anchor cables.

[0066] The specific steps include:

[0067] S2.1: In the numerical simulation software, all anchor cables are simultaneously moved from P1 to P n , the prestress is increased uniformly and gradually. In this embodiment, n=7; the applied prestresses are P1, P2, ..., P7 respectively. A total of 7 prestresses are applied.

[0068] Difference in application of adjacent prestressing forces

[0069] When all anchor cables are uniformly prestressed with P1, the peak bending moment generated by the bored pile is assumed to be M1;

[0070] When all anchor cables are uniformly prestressed with P2, the peak bending moment generated by the bored pile is assumed to be M2;

[0071] And so on…

[0072] When all anchor cables are uniformly prestressed with P7, the peak bending moment generated by the bored pile is assumed to be M7;

[0073] M1, M2, ..., M7 are obtained by simulation with numerical simulation software. For example, in the numerical simulation software, the prestress of all anchor cables is set to P1, and the numerical simulation software gives the bending moment at each cross section of the bored pile. Assuming that there are G cross sections, there are G bending moments. Comparing the G bending moments, the bending moment with the largest absolute value is the bending moment peak value M1.

[0074] In this embodiment, P1=0kN; P n =P7=600kN.

[0075]

[0076] S2.2: All anchor cables are uniformly prestressed from P1 to P n When the minimum bending moment peak value of bored pile is selected, it is recorded as M o,min ;

[0077] The formula is: M o,min =min{|M1|, |M2|, |M3|, |M4|, |M5|, |M6|, |M7|};

[0078] S2.3: According to the numerical simulation software, M o,min Input into the numerical simulation software to obtain the prestress P at this time o,min ; P o,min The same prestressing force is used as the reference prestressing force for all anchor cables.

[0079] In this embodiment, the value of the uniform prestress applied to each row of anchor cables and the corresponding peak bending moment generated by the bored piles are recorded in Table 1.

[0080] Table 1: Peak bending moment, minimum peak bending moment and reference prestress of bored piles under various prestressing conditions

[0081]

[0082]

[0083] From Table 1 we can see that:

[0084] When all anchor cables are uniformly prestressed with 0 kN, the peak bending moment M1 generated by the bored pile is 4145.598 kN·m;

[0085] When all anchor cables are uniformly prestressed with 100 kN, the peak bending moment M2 generated by the bored pile is 3169.498 kN·m;

[0086] And so on…

[0087] As shown in Table 1, when all anchor cables are uniformly prestressed with 400 kN, the peak bending moment generated by the bored pile is the smallest, and the minimum peak bending moment M o,min =M5=1125.824kN·m; at this time, the reference prestress P corresponding to M5 o,min It is 400kN.

[0088] Therefore, 400kN is uniformly used as the benchmark prestress for all anchor cables.

[0089] Figure 3 Displacement cloud diagram and bending moment diagram of bored piles when a benchmark prestress of 400kN is uniformly applied to all anchor cables. Figure 3 a is the displacement cloud diagram of bored pile; Figure 3 b is the bending moment diagram of bored cast-in-place piles.

[0090] S3: The prestress of each row of anchor cables is adjusted separately to obtain the corresponding optimal prestress of each row of anchor cables, and the first optimal bending moment peak value of the bored cast-in-place pile corresponding to the optimal prestress of each row of anchor cables is obtained.

[0091] The specific steps include:

[0092] S3.1: Number each row of anchor cables from top to bottom, denoted by k, k∈{1,2,3,4,5};

[0093] S3.2: Increase the prestress of the anchor cable numbered k=1 from P3, P4, ..., P7 step by step and evenly, and apply the difference between adjacent prestresses. Other anchor cables maintain the reference prestress P o,min ;

[0094] S3.3: The prestresses applied to the anchor cable numbered k=1 are P3, P 4、 ……, P7, other anchor cables maintain the reference prestress P o,min When the corresponding bending moment peaks generated by the bored piles are obtained, the prestressing force is applied 5 times for the anchor cable with the number k=1, and there are 5 corresponding bending moment peaks, which are recorded as Select The minimum bending moment peak value is denoted by

[0095]

[0096] The prestress of the anchor cable with number k=2 is increased gradually and evenly from P3, P4, ..., P7, and the anchor cables with other numbers maintain the reference prestress P o,min For the anchor cable with number k=2, five prestressing forces are applied, and there are five corresponding bending moment peaks, which are recorded as The minimum bending moment peak value of the anchor cable numbered k=2 is denoted as

[0097] And so on…

[0098] S3.4: Obtain the minimum peak bending moment of bored piles when all anchor cables are applied P3, P4, ..., P7, that is,

[0099] S3.5: Enter the values ​​in the numerical simulation software The minimum peak bending moment produced by each bored pile above corresponds to the optimal prestress applied by the bored pile;

[0100] Assume that the peak bending moment of bored pile is When , the optimal prestress output in the numerical simulation software is Input into numerical simulation software When the numerical simulation software outputs the corresponding optimal prestress

[0101] By analogy, the optimal prestress corresponding to the bored pile under different minimum bending moment peaks is obtained, which is recorded as The results are shown in Table 2.

[0102] Table 2 Peak bending moment of bored piles, minimum peak bending moment of bored piles and optimal prestress corresponding to minimum peak bending moment of bored piles for anchor cables of various numbers under prestress of P3, P4, ..., P7.

[0103]

[0104]

[0105] From Table 2, we know that when the anchor cable with number k=1 is subjected to 200kN prestress, the anchor cables with other numbers are subjected to the reference prestress P o,min =400kN, the peak bending moment of bored pile is 937.4796506kN·m;

[0106] For example, when the anchor cable with number k=1 is subjected to 300kN prestress, the anchor cables with other numbers are subjected to the reference prestress P o,min =400kN, the peak bending moment of bored pile is 890.9176138kN·m;

[0107] And so on…

[0108] The anchor cable with number k=1 is subjected to a prestress of 600 kN, and the anchor cables with other numbers are subjected to a reference prestress of P o,min =400kN, the peak bending moment of bored pile is 1626.10372kN·m;

[0109] According to Table 2 again, when 300 kN prestress is applied to the anchor cable with number k = 1 and the anchor cables with other numbers maintain the reference prestress, the peak bending moment of the bored pile is the smallest. The minimum peak bending moment of the bored pile is At this time, the optimal prestress corresponding to the anchor cable numbered k=1

[0110] And so on…

[0111] The optimal prestress corresponding to each numbered anchor cable is:

[0112] S3.6: Input the optimal prestress corresponding to each of the above-mentioned anchor cables into the numerical simulation software at the same time. Corresponding to the optimal prestress applied by anchor cable No. 1, Corresponding to the optimal prestress applied by anchor cable No. 2, and so on..., the first optimal bending moment peak value generated by the bored pile at this time is obtained t=1, the results are shown in Table 3.

[0113] Table 3: Bending moments of bored piles for anchor cables with different numbers under the corresponding optimal prestress.

[0114]

[0115] From Table 3, we know that

[0116] The first optimal bending moment peak value of bored piles under the optimal prestress corresponding to each numbered anchor cable It is 798.394 kN·m.

[0117] Figure 4 Displacement nephogram and bending moment diagram of bored cast-in-place piles under optimal prestress. Figure 4 a is the displacement cloud diagram of bored pile under prestress, Figure 4 b is the bending moment diagram under optimal prestress.

[0118] S4: Secondary adjustment of the optimal prestress of each row of anchor cables to obtain the final prestress of all anchor cables.

[0119] The specific steps include:

[0120] S4.1: Let t = 1; L = 2;

[0121] S4.2: Apply prestress P to the anchor cable numbered k=1 y， L∈{2,3,4,5,…,}, t∈{1,2,3,4,5,…,}; Assume that a total of u prestressing forces are applied, and u changes with the values ​​of L and t; the anchor cables with other numbers maintain the optimal prestressing force;

[0122] The anchor cable with number k=1 is prestressed P y When , the bored pile produces the corresponding bending moment peak; a total of u prestresses are applied, and a total of u bending moment peaks are produced by the bored pile, which are recorded as ……、

[0123] Apply prestress P to the anchor cable numbered k=2 y , L∈{2,3,4,5,…,}, t∈{1,2,3,4,5,…,}; Assume that a total of u prestressing forces are applied, and u changes with the values ​​of L and t; the anchor cables with other numbers maintain the optimal prestressing force;

[0124] The anchor cable with number k=2 is prestressed P y When the anchor cables with other numbers maintain the optimal prestress, the anchor cable with number k=2 is given the prestress P y The peak bending moment generated by the bored pile at the time is u times; a total of u prestressing forces are applied, and the bored pile generates a total of u times of bending moment peaks, which are recorded as

[0125] And so on…

[0126] S4.3: Select the bored pile with the smallest peak bending moment, denoted as Set as the t+1th optimal bending moment peak; and obtain The final prestress of each corresponding numbered anchor cable;

[0127] S4.4: Calculate the optimum bending moment ratio using the formula:

[0128]

[0129] S4.5: If ε<5% holds, output S4.3 t=1, the final prestress of each corresponding anchor cable;

[0130] If ε<5% does not hold, then let t=t+1, L=L+1, and repeat S4.2-S4.5 until ε<5% holds. Assumption: If it is established, the final prestress of each anchor cable at the Vth optimal bending moment peak value is output.

[0131] See Table 4 for specific data.

[0132] Table 4 Peak bending moment of each numbered anchor cable, minimum peak bending moment of bored piles and corresponding final prestress of each numbered anchor cable.

[0133]

[0134]

[0135] From Table 4, we know that

[0136] When the anchor cable numbered k=1 is subjected to a prestress of 200 kN alone and the anchor cables with other numbers are subjected to the corresponding optimal prestress, the peak bending moment of the bored pile is 852.0647338 kN·m;

[0137] When the anchor cable numbered k=1 is subjected to a prestress of 250 kN alone and the anchor cables numbered other are subjected to the corresponding optimal prestress, the peak bending moment of the bored pile is 825.6372451 kN·m;

[0138] And so on…

[0139] When t=1 is obtained, and from Table 4, when the anchor cable numbered k=4 is subjected to a prestress of 450 kN alone and the anchor cables numbered other are subjected to the corresponding optimal prestress, the minimum bending moment peak value generated by all bored piles is It is 766.8573363 kN·m, that is, the second optimal bending moment peak is 766.8573363 kN·m.

[0140] Because t=1,L=2, Therefore, the establishment conditions are met. According to Table 4, the output The corresponding final prestressing forces are, i.e., 300 kN, 300 kN, 500 kN, 450 kN, and 300 kN;

[0141] Figure 5 It is the displacement cloud diagram and bending moment diagram of bored piles when the final prestress is applied to each numbered anchor cable. Figure 5 a is the displacement cloud diagram of bored piles when the final prestress is applied to the anchor cables of each number; Figure 5 b is the bending moment diagram of bored piles when the final prestress is applied to the anchor cables of each number.

[0142] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for optimizing the prestressing of multiple rows of anchor cables, characterized in that: The following steps are involved: S1: Construct a bored pile support structure model containing multiple rows of anchor cables in numerical simulation software; S2: Uniformly determine the reference prestress of all anchor cables; S3: According to the reference prestress, the corresponding optimal prestress of each row of anchor cables is obtained respectively, and according to the optimal prestress corresponding to each row of anchor cables, the first optimal bending moment peak value generated by the bored pile is obtained; S4: Secondary adjustment of the optimal prestress of each row of anchor cables to obtain the second optimal bending moment peak value generated by the bored piles; Determine whether the second optimal bending moment peak value meets the set standard, and if so, obtain the prestress of each row of anchor cables corresponding to the second optimal bending moment peak value; If it does not meet the requirements, the optimal prestress in S3 is adjusted three times to obtain the third optimal bending moment peak value generated by the bored pile; and whether the third optimal bending moment peak value meets the set standard is determined again. And so on… Assuming that the Vth optimal bending moment peak value meets the standard, the prestress of each row of anchor cables corresponding to the Vth optimal bending moment peak value is obtained.

2. A method for optimizing prestressing of multiple rows of anchor cables according to claim 1, characterized in that: Step S2 includes the following steps: S2.1: In the numerical simulation software, all anchor cables are prestressed with P m , m∈{1,2,……,n}, prestress is applied to all anchor cables n times, and the prestress applied to all anchor cables in each prestress application is the same; As the number of times the prestress is applied increases, m increases accordingly, and the applied prestress P m It also increases accordingly; the difference between two adjacent prestressing forces: S2.2: When all anchor cables are subjected to a certain prestress P m When the external load and anchor cable force are combined, the bored pile will produce a corresponding peak bending moment. The peak bending moment is expressed as follows: when all anchor cables are subjected to the same or different prestress, different bending moments will be generated at each cross section of the bored pile. Assuming there are G cross sections in total, the bored pile will generate G bending moments. The moment with the largest absolute value among the G bending moments is the peak bending moment. When all anchor cables are subjected to n prestress P m When the prestress P of each anchor cable m Different, so the bored piles produce different peak moments; all anchor cables are added with n prestress P m , the bored pile generates n bending moment peaks; select the smallest bending moment peak among the n bending moment peaks, denoted as M o,min ; S2.3: According to the numerical simulation software, M o,min Input into the numerical simulation software to obtain the prestress P at this time o,min ; P o,min The same prestress is used as the base prestress for all anchor cables.

3. A method for optimizing prestressing of multiple rows of anchor cables according to claim 2, characterized in that: Step S3 includes the following steps: S3.1: Number each row of anchor cables from top to bottom, denoted by k, k∈{1,2,3,4,5}; S3.2: Apply prestress P to the anchor cable with number k = 1 j , j∈{3,4,……,n}, prestress P j As j increases, the difference in adjacent prestressing forces increases. The anchor cable with number k=1 is prestressed n-2 times. Each time the anchor cable with number k=1 is prestressed, the anchor cables with other numbers maintain the reference prestress P o,min ; The anchor cable with number k=1 is prestressed P j , other anchor cables maintain the reference prestress P o,min When the peak bending moment of the bored pile is obtained, the anchor cable numbered k=1 is applied with n-2 prestress P j , bored piles produce a total of n-2 bending moment peaks; Apply prestress P to the anchor cable numbered k=2 j , j∈{3,4,……,n}, prestress P j As j increases, the difference in adjacent prestressing forces increases. The anchor cable with number k=2 is prestressed n-2 times. Each time the anchor cable with number k=2 is prestressed, the anchor cables with other numbers maintain the reference prestress P o,min ; The anchor cable with number k=2 is prestressed P j , other anchor cables maintain the reference prestress P o,min When the peak bending moment of bored pile is obtained, the anchor cable with number k=2 is applied with n-2 prestress P j , bored piles produce a total of n-2 bending moment peaks; And so on… S3.3: Apply prestress P to the anchor cable with number k = 1 j When , compare the n-2 bending moment peaks and select the smallest bending moment peak among the n-2 bending moment peaks; record it as The anchor cable with number k=2 is prestressed P j When , the bored pile generates n-2 bending moment peaks in total. Compare the n-2 bending moment peaks and select the smallest bending moment peak among the n-2 bending moment peaks; record it as And so on… The minimum bending moment peak values ​​of anchor cables numbered 1 to 5 are recorded as follows: S3.4: Enter the values ​​in the numerical simulation software Each time the above-mentioned minimum bending moment peak is input into the numerical simulation software, an optimal prestress is correspondingly outputted in the numerical simulation software; Assume that the numerical simulation software inputs When the numerical simulation software outputs the corresponding optimal prestress Input into numerical simulation software When the numerical simulation software outputs the corresponding optimal prestress And so on… The optimal prestress outputted for each of the above-mentioned minimum bending moment peaks is: S3.5: Input all the optimal prestresses in S3.4 into the numerical simulation software simultaneously. Corresponding to the optimal prestress applied by anchor cable No. 1, This corresponds to the optimal prestress applied to the anchor cable numbered 2; and so on..., all anchor cables with corresponding numbers are corresponding to the optimal prestress applied; The peak bending moment generated by the bored pile at this time is obtained and set as the first optimal bending moment peak value, recorded as 4. A method for optimizing prestressing of multiple rows of anchor cables according to claim 3, characterized in that: Step S4 includes the following steps: S4.1: Set t=1, L=2; S4.2: Apply prestress P to the anchor cable numbered k=1 y， Assume that a total of u prestressing forces are applied, and u changes with the values ​​of L and t; the anchor cables with other numbers maintain the optimal prestressing force; The anchor cable with number k=1 is prestressed P y When the anchor cables with other numbers maintain the optimal prestress, the anchor cable with number k=1 is given the prestress P y The peak bending moment generated by the bored pile at the time is u times; a total of u prestressing forces are applied, and the bored pile generates a total of u times of bending moment peaks, which are recorded as Apply prestress P to the anchor cable numbered k=2 y， Assume that a total of u prestressing forces are applied, and u changes with the values ​​of L and t; the anchor cables with other numbers maintain the optimal prestressing force; The anchor cable with number k=2 is prestressed P y When , the bored pile produces the corresponding bending moment peak; a total of u prestresses are applied, and a total of u bending moment peaks are produced by the bored pile, which are recorded as And so on… S4.3: Select the bending moment peak with the smallest absolute value among all the bending moment peaks generated by bored piles in S4.2 and set it as the t+1th optimal bending moment peak, denoted as and obtain The final prestress of each corresponding numbered anchor cable; S4.4: Calculate the optimum bending moment ratio using the formula: S4.5: If ε<5%, it meets the set parameter standard and outputs the value in S4.

3. The final prestress of each corresponding numbered anchor cable; Otherwise, it does not meet the set parameter standard; if it does not meet the set parameter standard, then simultaneously substitute t=t+1 and L=L+1 into S4.2-S4.5 for the cycle; assuming: Then the final prestress of each numbered anchor cable under the Vth optimal bending moment peak value is output.

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