Discrimination Method for Mode Conversion of Dual-mode Shield

Abstract

The present invention relates to the field of determination of mode conversion methods in tunnel construction, and particularly to a discrimination method for mode conversion of a dual-mode shield. It aims to solve the problem that the best switching in the mode conversion of the dual-mode shield in the prior art cannot be actually determined. First, through the earth pressure in the soil chamber and the rock strength during the shield tunneling process, according to the influence factors of each parameter on the tunneling speed, key parameters are selected to fit and analyze the shield tunneling rate, establish the combined relationship between the tunneling parameters and the formation parameters, predict and analyze the tunneling efficiency of the dual-mode shield under different tunneling parameters and formation factors, and determine the difference in the tunneling rate through the construction period factor, and then determine the appropriate distance for the shield mode to convert to the TBM mode. The advantages are: achieving accurate determination at the moment of mode conversion and reducing construction costs.

Description

Technical Field

[0001] The present invention relates to the field of determination of mode conversion methods in tunnel construction, and particularly to a discrimination method for mode conversion of a dual-mode shield tunneling machine. Background Art

[0002] As the strata encountered during shield tunneling become increasingly complex, shield tunneling machines will increasingly frequently encounter long-distance soft rock and long-distance hard rock interaction intervals. The traditional tunnel excavation method is to set up an excavation shaft at the interface between soft and hard rocks, and use a single shield tunneling machine and a TBM to tunnel on both sides respectively. Due to the limited space in urban areas and the low efficiency of excavation shafts, which seriously affect traffic, the setting of shafts in soft-hard interaction strata has gradually been abandoned. With technological progress, a dual-mode shield tunneling machine that is suitable for both soft rock and hard rock strata has emerged. Currently, there are mainly three types of dual-mode shield tunneling machines: slurry-earth pressure, slurry-TBM, and earth pressure-TBM. Among them, the first two types of shield tunneling machines are assembled in parallel, realizing one-key mode conversion, which greatly improves the tunneling efficiency. However, for the TBM and earth pressure dual-mode shield tunneling machine, due to the large slag discharge equipment and the limited space inside the shield tunneling machine, only one type of slag discharge equipment can be installed. Therefore, a large amount of time is required for mode conversion, and generally the mode conversion time reaches 15 days.

[0003] During mode conversion, in order to improve the efficiency of mode conversion and tunneling, traditional dual-mode shield tunneling machines usually start mode conversion about 12 m away from the soft rock stratum when converting from TBM to EPB mode, and usually start mode conversion about 15 m after the EPB enters the hard rock stratum when converting from EPB to TBM mode. Mode conversion only considers the stratum factor and fails to consider the time factor of mode conversion, resulting in an extension of the construction period after mode conversion. It is very easy to perform mode conversion in sections where mode conversion is not necessary, resulting in low construction efficiency, wasting both costs and the construction period.

[0004] In the publicly disclosed patented technologies, there are two improvement methods for this technology. One is to achieve rapid mode conversion through equipment improvement, and the other is to accurately measure the rock stratum properties to shorten the conversion time.

[0005] To solve the necessity of mode conversion, the present invention determines from the difference in tunneling rates before and after mode conversion, comprehensively considers the mode conversion time, and then calculates the economic distance of mode conversion, thereby proposing a discrimination method for the mode conversion timing of a dual-mode shield tunneling machine. Summary of the Invention

[0006] The present invention provides a method for determining the necessity of mode conversion of a dual-mode shield tunneling machine considering tunneling efficiency and economic distance, which solves the problem of determining whether it is necessary to perform mode conversion for a dual-mode shield tunneling machine. By using the difference in tunneling speed before and after mode conversion and considering the mode conversion time, the differences between the tunneling distance and economic distance of different modes are determined, so that the dual-mode shield tunneling machine can achieve the best tunneling efficiency when tunneling in soft-hard alternating strata.

[0007] The method includes determining the tunneling distance of the dual-mode shield tunneling machine in different tunneling modes through geological exploration: during the geological exploration stage, collect the geological conditions of the tunnel, obtain the rock formation conditions and groundwater conditions of each excavation section of the tunnel, and preliminarily determine the mode conversion timing and mode conversion position. In the TBM rock tunneling section, the formation hardness is greater than 15 Mpa, and the face is ensured to be self-stable, with seepage less than 25 L / (min·10 m). According to the distribution of the detection sections, form the EPB earth tunneling sections [A1, A2, A3... AN] and the TBM rock tunneling sections [B1, B2, B3... BN];

[0008] (2) In the EPB earth tunneling section: within the formation position range of [A1, A2, A3... AN], by establishing the correlation analysis of tunneling parameters, determine the strongly correlated parameters of tunneling speed, cutter head rotation speed, torque, thrust, rock strength, and soil chamber pressure, and obtain the functional representation relationship.

[0009] In the formula: represents the functional relationship between the rotation speed and speed in the earth pressure mode; :

[0010] Among them: represents the functional relationship between the rotation speed and speed in the earth pressure mode; : the functional relationship between torque and speed; : the functional relationship between thrust and speed; : the functional relationship between the uniaxial compressive strength of rock and speed; : the functional relationship between the soil chamber pressure and speed, n is a constant related to the shield tunneling machine, and the coefficients of each function can be obtained by fitting;

[0011] (3) In the TBM rock tunneling section: within the formation position range of [B1, B2, B3... BN], by establishing the correlation analysis of tunneling parameters, determine the strongly correlated parameters of tunneling speed, cutter head rotation speed, torque, thrust, and rock strength, and obtain the calculation formula for the tunneling speed in the TBM mode: ;

[0012] Among them: is the functional relationship between the rotation speed and speed; is the functional relationship between torque and speed; is the functional relationship between thrust and speed; It is a functional relationship between the uniaxial compressive strength of rock and velocity. m is a constant related to TBM tunneling, and the coefficients of each function are obtained through fitting.

[0013] (3) Analyze the tunneling speeds of EPB and TBM under different tunneling modes according to the formation conditions and groundwater conditions, introduce the mode conversion time, and determine the position and timing of mode conversion;

[0014] When tunneling in hard rock formations, it is considered that: > ,

[0015] It is obtained that:

[0016] Among them, the mode conversion time T generally takes 12 - 15 days;

[0017] (4) Judgment result: In step 3, during the mode conversion process, if the hard rock tunneling distance is less than the economic distance S, it is recommended to perform mode conversion, otherwise, do not perform mode conversion.

[0018] It can also be that in steps (2) and (3), when the distance parameters in the earth tunneling sections [A1, A2, A3... AN] and the TBM rock tunneling sections [B1, B2, B3... BN] are less than 50 meters and are distributed in an alternating and staggered manner, new sample earth tunneling sections [A1', A2', A3'... AN'] and TBM rock tunneling sections [B1', B2', B3'... BN'] are formed in the form of eliminating and supplementing to the upper - level data.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention determines the tunneling distances of the dual - mode shield under different tunneling modes through geological exploration, judges the formation lithology and groundwater conditions according to geological data, and preliminarily determines the mode conversion timing and mode conversion position. The EPB mode is selected for tunneling in sections with rich groundwater, and the TBM mode is selected in full - section hard rock formations without groundwater or with slight seepage and humidity of groundwater. Analyze the tunneling speeds of EPB and TBM under different tunneling modes according to the formation conditions and groundwater conditions, consider the mode conversion time, and determine the position and timing of mode conversion.

[0021] The present invention solves the discrimination problem of whether it is necessary to perform mode conversion for the dual - mode shield from the aspects of tunneling efficiency and construction period. Through the analysis of the economic distance, the mode conversion of the dual - mode shield has obvious economy, and greatly improves the tunneling efficiency of the dual - mode shield. Brief Description of the Drawings

[0022] Figure 1 It is a schematic flow diagram of the present invention;

[0023] Figure 2This is a schematic diagram of the principle of the present invention. Detailed implementation manners

[0024] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Embodiment 1

[0025] A method for judging the necessity of mode conversion of a dual-mode shield tunneling machine, see Figures 1 to 2 , including the following steps: (1) Determine the tunneling distance of the dual-mode shield tunneling machine in different tunneling modes through geological exploration: During the geological exploration stage, collect the geological conditions of the tunnel, obtain the rock formation conditions and groundwater conditions of each excavation section of the tunnel, preliminarily determine the mode conversion timing and mode conversion position, and form an EPB earth excavation section [A1, A2, A3... AN] and a TBM rock excavation section [B1, B2, B3... BN]. In the TBM rock excavation section, the formation hardness is greater than 15 Mpa, and the face is ensured to be self-stable, with little or no groundwater

[0026] (2) In the EPB earth excavation section: By analyzing various factors of the tunneling speed, a functional representation relationship can be obtained.

[0027] In the formula: represents the functional relationship between the rotation speed and the speed in the earth pressure mode;

[0028] (Formula 1):

[0029] In Formula 1: represents the functional relationship between the rotation speed and the speed in the earth pressure mode; : The functional relationship between torque and speed; : The functional relationship between thrust and speed; : The functional relationship between the uniaxial compressive strength of rock and speed; : The functional relationship between the earth pressure in the soil bin and speed, where n is a constant related to the shield tunneling machine;

[0030] In the TBM rock excavation section: By analyzing various factors of the tunneling speed, the calculation formula for the tunneling speed in the TBM mode is obtained: (Formula 2);

[0031] In Formula 2: is the functional relationship between the rotation speed and the speed; is the functional relationship between torque and speed; is the functional relationship between thrust and speed; is the functional relationship between the uniaxial compressive strength of rock and speed, and m is a constant related to TBM tunneling.

[0032] (3)Analyze the tunneling speed of EPB and TBM under different tunneling modes according to the formation conditions and groundwater conditions, introduce the mode conversion time, and determine the location and timing of mode conversion;

[0033] When tunneling in hard rock formations, it is considered that: > ,

[0034] It is obtained that:

[0035] Among them, the mode conversion time T is obtained through similar engineering cases, and it is taken as 12 - 15 days.

[0036] In this embodiment, according to the calculation results, it is obtained that > . Therefore, the conclusion also supports that for a double - mode shield tunneling machine under the condition of considering the mode conversion time, it is necessary to analyze the economic distance of mode conversion.

[0037] The formula in this embodiment is a self - developed formula, and the functional relationship therein is determined with reference to the functional relationship in the prior art. In the measurement step, the measurement method and tools are subject to what can be achieved by the prior art.

[0038] Comprehensively consider the effective time and ineffective time during the tunneling process of the shield / TBM.

[0039] Among them: f(N) is the functional relationship between rotational speed and speed; f(T) is the functional relationship between torque and speed; f(F) is the functional relationship between thrust and speed; f(Q) is the functional relationship between uniaxial compressive strength of rock and speed. Through parameter regression analysis, it is obtained that:

[0040] V = 2.3N + 0.006T + 0.000138F - 0.002Q + 3.67, where N (r / min); T(KN·m); F (kN); Q (MPa). In the TBM mode, the tunneling parameters are N = 2.5 - 3; T = 1500 - 2000; F = 10000 - 13000; Q = 90 - 100

[0041] It is calculated that = 19.62 - 24.164 (mm / min).

[0042]

[0043] In the formula: represents the functional relationship between rotational speed and speed in the earth pressure mode; : the functional relationship between torque and speed; : the functional relationship between thrust and speed; : Functional relationship between uniaxial compressive strength of rock and speed; : Functional relationship between chamber pressure and speed;

[0044] Through parameter regression analysis, it is obtained that:

[0045] =7.2e0.147N + 0.002T + 0.0001F - 0.002Q - 7.61σ + 8.9, where N (r / min); T (KN·m); F (kN); Q (MPa); σ (bar); During tunneling in earth pressure mode, the tunneling parameters are N = 1.8~2.0; T = 1500~2500; F = 13000~17000; Q = 90~100; σ = 1.3~1.8

[0046] Calculated: =11.38~12.52 (mm / min).

[0047] By analyzing the TBM tunneling time, it is obtained that the effective time accounts for 21% of the total calculated time. During shield tunneling, the effective time accounts for 29% of the total calculated time. The ineffective time includes the shutdown waiting time, inspection and maintenance time, and cutter changing time during the mucking process. Comprehensively consider the effective time and ineffective time during shield / TBM tunneling.

[0048] =24 (h)×60 (min)×(19.62~24.164 (mm / min))×21% / 1000 = 5.93~7.31 (m / d)

[0049] =24 (h)×60 (min)×(11.38~12.52 (mm / min))×29% / 1000 = 4.75~5.23 (m / d)

[0050] Considering the mode conversion time of 12~15 days, the economic distance of mode conversion can be calculated.

[0051] =286.45~358.05m

[0052] By comparing the economic distance with the designed tunneling distance, during the mode conversion process, if the hard rock tunneling distance is less than the economic distance, it is recommended to carry out mode conversion, otherwise it is not recommended. Therefore, during the mode conversion process, in actual engineering, due to the hard rock distance of 260m being less than the calculated economic distance, the mode conversion could not be carried out, saving about 5 days compared to the designed calculation construction period.

[0053] By determining the economic distance of mode conversion, the tunneling efficiency of the dual-mode shield can be improved and the waste of construction period can be avoided. Example 2

[0054] The working steps of this embodiment are the same as those of Embodiment 1. The specific difference is that in steps (2) and (3), when the parameters in the soil excavation sections [A1, A2, A3... AN] and the TBM rock excavation sections [B1, B2, B3... BN] are less than 50 meters and are distributed at intervals and staggered, new sample soil excavation sections [A1', A2', A3'... AN'] and TBM rock excavation sections [B1', B2', B3'... BN'] are formed in the form of eliminating and supplementing to the upper-level data.

[0055] For example, for the original sample soil excavation sections [206, 20, 60, 300] and the rock excavation sections [360, 300, 200, 50], after overall fitting, the data are soil excavation 206, rock excavation 360, soil excavation 20, rock excavation 200, soil excavation 60, rock excavation 200, soil excavation 300, rock excavation 50. Here, in order to reduce the time wasted by frequent replacement, the too-small samples are eliminated.

[0056] Updated to soil excavation 206, rock excavation 380, rock excavation 300, soil excavation 60, rock excavation 200, soil excavation 350

[0057] Resample the soil excavation sections [206, 60, 350] and the TBM rock excavation sections [680, 200]; calculate again with the data of this quantity level, and small samples can be slightly eliminated to reduce the calculation amount and construction cost.

[0058] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A discrimination method for the mode conversion of a TBM & EPB dual-mode shield, characterized in that, The steps are as follows: (1) Determine the tunneling distance of the double-mode shield in different tunneling modes through geological exploration: During the geological exploration stage, collect the geological conditions of the tunnel, obtain the rock formation conditions and groundwater conditions in each excavation section of the tunnel, preliminarily determine the mode conversion timing and position. In the TBM rock tunneling section, the formation hardness is greater than 15 Mpa, and the face is ensured to be self-stable, with seepage less than 25 L / (min·10 m). According to the distribution of the detection sections, form the EPB earth tunneling sections [A1, A2, A3... AN] and the TBM rock tunneling sections [B1, B2, B3... BN]; (2) In the EPB earth tunneling section: In the formation position range of [A1, A2, A3... AN], through establishing the correlation analysis of tunneling parameters, determine the strongly correlated parameters of tunneling speed, cutterhead rotation speed, torque, thrust, rock strength and soil chamber pressure, and obtain the functional representation relationship, In the formula: represents the functional relationship between the rotation speed and the speed in the earth pressure mode; ： Wherein: represents the functional relationship between the rotational speed and the speed under the earth pressure mode; : the functional relationship between the torque and the speed; : the functional relationship between the thrust and the speed; : the functional relationship between the uniaxial compressive strength of the rock and the speed; : the functional relationship between the chamber pressure and the speed, where n is a constant related to the shield, and the coefficients of each function can be obtained by fitting; (3) In the rock excavation section of the TBM: within the formation position range of [B1, B2, B3... BN], by establishing a correlation analysis of tunneling parameters, determine the strongly correlated parameters of tunneling speed, cutterhead rotation speed, torque, thrust, and rock strength, and obtain the calculation formula for tunneling speed under the TBM mode: ; Wherein: is the functional relationship between rotational speed and velocity; is the functional relationship between torque and velocity; is the functional relationship between thrust and velocity; is the functional relationship between the uniaxial compressive strength of rock and velocity, where m is a constant related to TBM tunneling, and the coefficients of each function are obtained by fitting; Analyze the tunneling speeds of the EPB and the TBM in different tunneling modes according to the formation conditions and groundwater conditions, introduce the mode conversion time, and determine the position and timing of the mode conversion; When tunneling in hard rock formations, it is considered that: > : ; It is concluded that: ; Among them, the mode conversion time T is generally taken as 12 - 15 days; (4) Judgment result: In step 3, during the mode conversion process, if the hard rock tunneling distance is less than the economic distance S, it is recommended to carry out the mode conversion, otherwise, do not carry out the mode conversion.

2. The discrimination method for the mode conversion of a TBM & EPB dual-mode shield according to claim 1, characterized in that: In steps (2) and (3), when the distance parameters in the earth tunneling sections [A1, A2, A3... AN] and the TBM rock tunneling sections [B1, B2, B3... BN] are less than 50 meters and are distributed in an alternating interval manner, new sample earth tunneling sections [A1', A2', A3'... AN'] and TBM rock tunneling sections [B1', B2', B3'... BN'] are formed in the form of eliminating and supplementing to the upper-level data.

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