A synchronous double slurry mixing ratio comprehensive optimization method for waste mud

Abstract

The application relates to the technical field of shield tunnel construction, and discloses a comprehensive optimization method for a synchronous double-liquid slurry mixing ratio of waste mud, which comprises the following steps: testing the performance indexes of cement-soil slurry-water glass double-liquid slurry based on target factors, determining economic indexes; determining fitting formulas of the performance indexes and the economic indexes about the target factors; determining the value range of the performance indexes and the mud specific gravity; solving all target factor combinations meeting the synchronous grouting performance indexes and the tunneling mud requirements; calculating the comprehensive evaluation indexes of each target factor combination based on the comprehensive performance index measurement index, the economic index measurement index and the performance index comprehensive anti-interference ability measurement index; and determining the mud, cement, retarder and water glass mass based on the value of the target factors in the best target factor combination, so that the mixing ratio of the synchronous double-liquid slurry of the waste mud is obtained. The application realizes comprehensive optimization of the mixing ratio, and improves the scientificity and rationality of the mixing ratio design.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel construction technology, and more specifically, to a method for comprehensively optimizing the mix proportion of waste mud with two liquid slurry. Background Technology

[0002] Because the outer diameter of the tunnel boring machine (TBM) shield is larger than the outer diameter of the tunnel segments, a gap exists between the segments and the ground after the segments exit the shield tail. As the TBM advances, grouting must be performed simultaneously to fill this gap, preventing ground deformation and tunnel displacement. Traditional single-component inert grout and single-component rigid grout are not effective in controlling segment uplift. In recent years, large-diameter shield tunnels have widely adopted cement-water glass dual-component grout as the simultaneous grouting material. Its rapid gelation characteristic effectively inhibits segment uplift and reduces surface settlement. The cement-water glass dual-component grout used in simultaneous grouting includes cement slurry (component A) and water glass solution (component B). Component A mainly consists of cement, bentonite, retarder, and water.

[0003] In existing engineering practices, the conventional method for preparing cement-water glass two-component grout is to determine the range of values ​​for indicators such as the bleeding rate of component A and the gel time and strength of the mixture of components A and B, based on relevant standards for synchronous grouting, the requirements of the construction unit, or on-site testing. Then, the mixing ratio of the two-component grout is controlled using key parameters such as the water-cement ratio, the retarder dosage, the bentonite dosage, and the volume ratio of component A to component B, to obtain a synchronous grout that meets construction requirements. This method has been applied to several large-diameter shield tunnels and has proven effective.

[0004] In addition, shield tunnel construction generates a large amount of construction waste or waste slurry. For slurry shield tunnels, the slurry discharged from the slurry pipe, even after slurry-water separation, is still a huge quantity. Re-mixing it for reuse as tunneling slurry cannot completely eliminate the waste, and the remaining slurry is discarded, requiring dewatering into excavated soil before transportation. This process is complex, time-consuming, and costly. However, the soil particles in the slurry after slurry-water separation are smaller and can be used to prepare the A-liquid of the simultaneous two-liquid slurry. Current research has verified the feasibility of using soil particles from the slurry after slurry-water separation to replace the bentonite in the simultaneous two-liquid slurry, but its practical application in engineering is almost nonexistent.

[0005] Previously, the preparation of simultaneous grouting slurry using waste mud or slag was more commonly applied to single-liquid slurries because single-liquid slurries contain sand and bentonite, and have lower requirements for waste mud. However, methods for preparing simultaneous two-liquid slurries are still immature. The current technical approach often involves processing waste mud into slag or mud cakes, then adding water to prepare the slurry, directly providing the mass of each material component of the simultaneous grouting slurry. This existing technology still has the following shortcomings:

[0006] 1) The biggest characteristic of waste mud is its unstable properties. The mud obtained from different projects, different strata and different treatment methods varies greatly. If the existing component ratios are used directly, the performance of the slurry cannot be guaranteed. In addition, the existing mixing ratios are basically for single-liquid slurries. The material composition of two-liquid slurries is quite different from that of single-liquid slurries.

[0007] 2) The current synchronous two-liquid grout mix ratio is controlled by the water-cement ratio, the amount of retarder, and the volume ratio of liquid A and liquid B. However, the above parameters are easily disturbed during construction, resulting in a large deviation between the actual value and the design value, which affects the quality of synchronous grouting.

[0008] 3) Existing methods for designing the mix proportion of waste mud synchronous grouting materials mainly rely on orthogonal experiments, empirical design, or single performance indicators to determine the mix proportion. They usually take meeting the grout performance requirements or minimizing material costs as the optimization goal, and lack a comprehensive evaluation of the impact of grout performance, economy, and fluctuations in key parameters during construction.

[0009] 4) Current materials are not only complex in composition and expensive, but also have a low proportion of waste mud, so the effect on saving costs in waste mud treatment and simultaneous grouting is not significant.

[0010] Therefore, this invention addresses the problems of unstable waste mud properties, difficulty in accurately controlling construction parameters, single basis for determining mix proportions, and low mud utilization rate by proposing a comprehensive optimization method for the mix proportion of waste mud in a simultaneous two-liquid slurry process. Summary of the Invention

[0011] To address the problems in related technologies, this invention proposes a comprehensive optimization method for the proportion of waste mud in a simultaneous two-liquid mixture, in order to overcome the aforementioned technical problems existing in the existing related technologies.

[0012] Therefore, the specific technical solution adopted by the present invention is as follows:

[0013] A method for comprehensive optimization of the mix proportion of waste mud using a simultaneous two-liquid slurry method includes:

[0014] Based on the target factors, the performance indicators of cement-soil slurry-water glass two-liquid slurry were tested by orthogonal experiment, and the economic indicators were determined. The target factors were slurry specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio.

[0015] Multiple regression fitting was performed on the orthogonal test results to obtain the fitting formulas for the performance and economic indicators of cement-soil grout-water glass double liquid grout with respect to the target factors.

[0016] Based on industry standards and project grouting requirements, the range of values ​​for the performance indicators of cement-soil grout-water glass dual-liquid grout was determined, and the range of values ​​for the grout specific gravity was determined based on the geological characteristics.

[0017] Using the range of performance indicators and mud specific gravity as constraints, and combining the fitting formula, we solve for all the target factor combinations that meet the performance indicators of synchronous grouting and the requirements of tunneling mud.

[0018] Based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, calculate the comprehensive evaluation index of each target factor combination in the target factor combination set.

[0019] The optimal combination of target factors is determined based on the calculation results of the comprehensive evaluation index. Based on the values ​​of the target factors in the optimal combination of target factors, the quality of mud, cement, retarder and water glass is determined, and the mix proportion of waste mud synchronous two-liquid slurry is obtained.

[0020] Among them, based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, the comprehensive evaluation index of each target factor combination in the target factor combination set is calculated, including:

[0021] Based on the target factor combination set obtained by the solution, the extreme values ​​of the range of each performance index and economic index are determined, and the fluctuation values ​​of mud specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio during the construction process are determined.

[0022] Each performance index in each group of target factors is converted to the corresponding extreme value of the range without dimension, and the performance index of each performance index in the target factor combination is determined. The comprehensive performance index of cement-soil slurry-water glass double liquid slurry is obtained by weighted summation in combination with preset performance weights.

[0023] The economic indicators and their corresponding extreme values ​​in each group of target factors are converted into dimensionless values ​​to obtain the economic index of cement-soil slurry-water glass double liquid slurry.

[0024] The deviation of each performance index is calculated by using the fitting formula when each target factor fluctuates positively and negatively at the preset fluctuation amplitude. The sensitivity of each performance index to construction disturbance is determined based on the deviation. After the sensitivity is converted into a dimensionless value in reverse, it is weighted and summed according to the preset performance weight to obtain the comprehensive anti-interference ability index of the cement-soil slurry-water glass dual liquid slurry.

[0025] Based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, the comprehensive evaluation index of each target factor combination is obtained by weighting and summing the indexes according to the preset index weights.

[0026] The optimal combination of target factors is determined based on the calculation results of the comprehensive evaluation index. Based on the values ​​of the target factors in the optimal combination, the quality of mud, cement, retarder, and water glass is determined, resulting in the mix proportion of the waste mud for simultaneous two-liquid slurry production.

[0027] Based on the calculation results of the comprehensive evaluation index of each target factor combination in the target factor combination set, the target factor combination with the largest comprehensive evaluation index is selected as the optimal target factor combination.

[0028] The specific gravity of the mud, the water-cement ratio, the dosage of retarder and the alkali-cement ratio are determined based on the optimal combination of target factors. The setting time of the cement-soil slurry in the optimal combination of target factors is verified. When the setting time does not meet the preset time threshold, the determined dosage of retarder is adjusted.

[0029] Based on the determined mud specific gravity, water-cement ratio, alkali-cement ratio, and adjusted retarder dosage, combined with the pre-determined mass of soil particles and water in the mud, the mass of mud, cement, retarder, and water glass to be added is calculated, and the mix proportion of waste mud synchronous two-liquid slurry is obtained.

[0030] The beneficial effects of this invention are as follows:

[0031] 1) This invention establishes a comprehensive evaluation index, which no longer determines the mix proportion based solely on a single performance or economic indicator, but comprehensively considers the slurry performance, economy and anti-fluctuation ability, thereby achieving comprehensive optimization of the mix proportion and improving the scientificity and rationality of the mix proportion design. This method can also be simplified and extended to ordinary cement-water glass two-liquid slurry.

[0032] 2) This invention fully considers the impact of fluctuations in target factors on slurry performance during construction. Taking the most unfavorable working condition in which four target factors simultaneously deviate in the same direction as the evaluation benchmark, it proposes a comprehensive anti-interference ability measurement index for performance indicators. Based on the actual technical level of the construction unit, it can select a mix ratio with better construction adaptability and improve the reliability of synchronous dual-liquid slurry construction.

[0033] 3) This invention takes into account the adjustment and changes of mud parameters in different strata, and can quickly adjust the mix ratio according to the changes in strata to ensure the stable performance of cement-soil slurry-water glass dual-liquid slurry, which can improve the construction quality of synchronous grouting and avoid problems such as segment floating and ground settlement caused by the deterioration of slurry performance.

[0034] 4) The cement-soil slurry-water glass dual-liquid slurry material of the present invention uses tunneling mud as the main raw material. The mud accounts for more than 70% of the total mass of the dual-liquid slurry, and the amount of cement and water glass used is reduced accordingly. This can reduce the amount of mud waste, save the cost of waste slurry dewatering and transportation, and directly reduce the cost of cement and water glass. Compared with conventional cement-water glass dual-liquid slurry, the overall cost savings can exceed 50%.

[0035] 5) The soil particle content in the cement-soil slurry-water glass dual-liquid slurry of the present invention is much higher than the bentonite content in conventional cement-water glass dual-liquid slurry, which can more fully fill the micropores formed by the reaction products of cement and water glass, thereby improving the density of the product and enhancing its durability without weakening the performance of the synchronous grouting slurry.

[0036] 6) The raw material of the mud of the present invention can be obtained by processing existing and necessary mud-water separation equipment. It can be used for shield tunneling and preparation of synchronous dual-liquid slurry at the same time, realizing dual use of one slurry. No additional process or equipment is required. It has good construction convenience and economy, and is easy to promote and use. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a flowchart of a method for comprehensive optimization of the mix proportion of waste mud in a simultaneous two-liquid slurry process according to an embodiment of the present invention;

[0039] Figure 2 This is a mud particle size distribution curve diagram according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the solution code according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of a pre-screening device according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of a cyclone device according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of sludge entering the sedimentation tank according to an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the slurry in the slurry mixing tank according to an embodiment of the present invention;

[0045] Figure 8 This is a comparison diagram of the durability of cement-soil grout-water glass dual-liquid grout and cement-water glass dual-liquid grout according to embodiments of the present invention. Detailed Implementation

[0046] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0047] Example 1

[0048] like Figure 1 As shown, a method for comprehensive optimization of the mix proportion of waste mud using a simultaneous two-liquid slurry method includes:

[0049] S1. Based on the target factors (i.e. key factors), the performance indicators of cement-soil slurry-water glass double-liquid slurry were tested by orthogonal experiments, and the economic indicators were determined. Among them, the target factors are slurry specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio.

[0050] The cement-soil slurry includes mud, cement, and retarder. The mud is the excavation mud obtained by separating the slag-carrying mud generated by the slurry-water balance shield tunneling. The proportion of particles with a diameter greater than 100μm in the excavation mud is less than or equal to 5%. The reason is that when the soil particles are large, they are prone to sedimentation, which leads to water bleeding in the cement-soil slurry. Therefore, the proportion is controlled to not exceed 5% under the premise of considering the actual capacity of the mud-water separation equipment.

[0051] Specifically, the performance indicators that must be measured in orthogonal experiments include the 3-hour bleeding rate of cement-soil slurry, the gel time of cement-soil slurry mixed with water glass, the 1-day unconfined compressive strength, and the 28-day unconfined compressive strength. These can be tested according to the methods in the standards, such as the "Technical Specification for Application of Synchronous Grouting Materials in Shield Tunneling" (CECS 563-2018).

[0052] The economic indicator is the combined cost-saving ratio of simultaneous grouting and waste mud treatment. Specifically, it represents the cost savings compared to using conventional cement-water glass dual-liquid grout, after deducting the reduced waste mud treatment cost, when injecting the same volume of simultaneous grout using the simultaneous two-liquid grout material of this invention. This indicator measures the cost-saving ratio of the technology used in this invention; a higher value indicates better economic efficiency.

[0053] Because mud specific gravity is the most critical indicator in tunnel boring machine (TBM) specifications, and based on existing tests, it has the most significant impact on the bleeding rate of cement-soil slurry-water glass dual-liquid slurry, and also has a certain influence on the 1-day and 28-day unconfined compressive strength, this indicator is chosen to control mud raw materials. The mud specific gravity value should cover the applicable range for different geological formations in the project. Generally, the usable range for mud specific gravity is... .

[0054] The water-cement ratio is the ratio of the mass of water to the mass of cementitious material in cement slurry. Cement is the most commonly used cementitious material. If no additional water is added, the mass of water is the same as the mass of water contained in the slurry; otherwise, the mass of additional water must be added. Based on existing experiments, the water-cement ratio has the greatest impact on the 28-day unconfined compressive strength, and also affects the 1-day unconfined compressive strength and bleeding rate. Lowering the water-cement ratio is beneficial for improving performance indicators, but it increases costs. The water-cement ratio can be selected in the range of 2.5 to 4.0.

[0055] The retarder dosage is the ratio of the retarder's mass to the mass of the cementitious material. Since there are many different types of retarders with varying dosages, the retarder dosage should be determined by the manufacturer's recommendations or after conducting preliminary tests.

[0056] The alkali-cement ratio is the ratio of the mass of water glass to the mass of the cementitious material. Based on existing experiments, the alkali-cement ratio has a significant impact on the gel time of the cement paste mixed with water glass solution, as well as the unconfined compressive strength at 1 day and 28 days. A lower alkali-cement ratio results in a shorter gel time and lower compressive strength. However, since the unconfined compressive strength can be simultaneously controlled by other parameters, determining the alkali-cement ratio hinges on the gel time. It is recommended that the alkali-cement ratio be selected between 0.25 and 0.55.

[0057] S2. Perform multiple regression fitting on the orthogonal test results to obtain the fitting formulas for the performance and economic indicators of cement-soil slurry-water glass double liquid slurry with respect to the target factors.

[0058] Specifically, fitting analysis can be performed using data analysis software such as Origin, SPSS, and Excel. When fitting multiple regressions, multiple linear polynomials are preferred, and the coefficient of determination is... Linear fitting can be used when the coefficient of determination is greater than or equal to 0.7, and greater than 0.9 is preferred; when the coefficient of determination is... When the coefficient of determination is less than 0.7, a multivariate nonlinear quadratic polynomial can be used for fitting, and the coefficient of determination must be satisfied. Not less than 0.7.

[0059] Specifically, the fitting formulas for the performance and economic indicators with respect to the target factors are as follows:

[0060] ;

[0061] ;

[0062] ;

[0063] ;

[0064] ;

[0065] In the formula, The water bleeding rate of cement-soil slurry after 3 hours; The gelation time of the mixture of cement slurry and water glass is expressed in seconds. The unconfined compressive strength over 1 day is expressed in MPa. The unconfined compressive strength at 28 days is expressed in MPa. The ratio of the combined costs of simultaneous grouting and waste mud treatment to savings; This refers to the specific gravity of the mud, in units of... ; This refers to the water-to-binder ratio; This refers to the dosage of retarder; The alkali-to-gum ratio is... These are fitting functions for the 3-hour bleeding rate of cement-soil grout, the gel time of cement-soil grout mixed with water glass, the 1-day unconfined compressive strength, the 28-day unconfined compressive strength, and the ratio of the saved cost of simultaneous grouting to the comprehensive cost of waste mud treatment.

[0066] S3. Based on industry standards and project grouting requirements, determine the range of values ​​for the performance indicators of cement-soil grout-water glass dual-liquid grout, and determine the range of values ​​for the grout specific gravity based on the geological characteristics.

[0067] The grouting requirements for the project include the requirements of the construction unit and the design unit, as well as the characteristics of the grouting equipment used by the construction unit.

[0068] Specifically, the 3-hour bleeding rate of cement slurry should not exceed 10%, based on standards and experience.

[0069] The gelation time of cement slurry and water glass mixture depends on the length of the grouting pipeline after mixing. If the grouting pipeline is about 8m long, it is generally required to be 15s to 21s based on experience. If the shield tail mixing is used, it is required to be within 10s.

[0070] The unconfined compressive strength at 1 day and 28 days is generally required to be no less than 0.2 MPa and 1.0 MPa, respectively.

[0071] The above indicators are all derived from engineering practice experience and existing standards. The actual values ​​shall be based on the specific project requirements.

[0072] The usable range of mud specific gravity is: Because clay soil strata contain many clay particles, if the excavation mud has a high specific gravity, the discharged mud will also have a high specific gravity, making pumping difficult. Therefore, a smaller value is used for clay soil strata. On the other hand, gravel and hard rock strata require mud with a higher specific gravity to carry gravel and sand. If the specific gravity is too low, it cannot be carried out. Therefore, a larger value is used for gravel and hard rock strata.

[0073] S4. Using the range of performance indicators and mud specific gravity as constraints, and combining the fitting formula, solve for all the target factor combinations that meet the synchronous grouting performance indicators and tunneling mud requirements.

[0074] S5. Based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, calculate the comprehensive evaluation index of each target factor combination in the target factor combination set.

[0075] Among them, based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, the comprehensive evaluation index of each target factor combination in the target factor combination set is calculated, including:

[0076] S51. Based on the target factor combination set obtained from the solution, determine the extreme values ​​of the range of each performance index and economic index, and determine the fluctuation values ​​of mud specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio during the construction process.

[0077] S52. Dimensionlessly convert each performance index in each target factor combination to its corresponding extreme value range, determine the merit score of each performance index in the target factor combination, and obtain the comprehensive performance index of cement-soil slurry-water glass dual-liquid slurry by weighted summation in combination with preset performance weights.

[0078] Specifically, the performance index is determined in terms of its merits or demerits within the combination of target factors, including:

[0079] 1) The score for the 3-hour bleeding rate of cement slurry is determined by dividing the difference between the maximum and minimum bleeding rates in the target factor combination by the difference between the maximum and minimum bleeding rates; the calculation formula is:

[0080] ;

[0081] In the formula, This is the index for measuring the 3-hour bleeding rate of cement-soil slurry under the i-th combination of target factors, i.e., the score for the quality of the 3-hour bleeding rate of cement-soil slurry. The 3-hour bleeding rate of cement-soil slurry under the i-th combination of target factors. The calculation results For all combinations The maximum and minimum values ​​of the calculation results.

[0082] 2) The score for the gel time of the cement slurry mixed with water glass is determined by dividing the smaller of the distances from the minimum gel time and the maximum gel time in the target factor combination by the average of the minimum and maximum gel times; the calculation formula is:

[0083] ;

[0084] In the formula, This is an index measuring the gel time of the cement-soil slurry mixed with water glass under the i-th combination of target factors, i.e., a score indicating the quality of the gel time of the cement-soil slurry mixed with water glass. The gelation time of the cement-soil mixture and water glass under the i-th combination of target factors. The calculation results For all combinations The maximum and minimum values ​​of the calculation results.

[0085] 3) The score for 1-day unconfined compressive strength is determined by dividing the difference between the strength value and the minimum strength value in the target factor combination by the difference between the maximum strength value and the minimum strength value; the calculation formula is:

[0086] ;

[0087] In the formula, This is the index for measuring 1-day unconfined compressive strength under the i-th combination of target factors, i.e., the score for the quality of 1-day unconfined compressive strength. The 1-day unconfined compressive strength under the i-th combination of target factors The calculation results For all combinations The maximum and minimum values ​​of the calculation results.

[0088] 4) The score for the 28-day unconfined compressive strength is determined by dividing the difference between the strength value and the minimum strength value in the target factor combination by the difference between the maximum strength value and the minimum strength value; the calculation formula is:

[0089] ;

[0090] In the formula, This is the index for measuring 28-day unconfined compressive strength under the i-th combination of target factors, i.e., the score for the quality of 28-day unconfined compressive strength. The 28-day unconfined compressive strength under the i-th combination of target factors The calculation results For all combinations The maximum and minimum values ​​of the calculation results.

[0091] The formula for calculating the comprehensive performance index of cement-soil grout-water glass two-component grout is as follows:

[0092] ;

[0093] In the formula, It is a comprehensive performance index for cement-soil grout-water glass two-component grout, and The value is between 0 and 1. The weights for the following factors are respectively: 3-hour bleeding rate of cement-soil slurry; gel time of cement-soil slurry mixed with water glass; 1-day unconfined compressive strength; and 28-day unconfined compressive strength. .

[0094] in, The selection principle is as follows: Unless there are special circumstances, a balanced approach can be taken, with all values ​​taking 1 / 4. The 3-hour bleeding rate of cement-soil slurry is mainly used to ensure the quality of the slurry during storage. If the slurry needs to be stored for a long time after mixing, then... The gel time should be appropriately increased to 0.3-0.4. Since the gel time is significantly affected by various target factors, and this parameter has a very large impact on construction, if it is too small, it is easy to clog the pipe; if it is too large, it is easy to reduce the quality of synchronous grouting. This is especially important when there are high requirements for controlling the rise of the pipe segments or when the groundwater flow velocity is high (greater than 100 km / h). When environmental protection requirements are high, its corresponding The value should be increased to 0.3~0.4; the long-term strength of cement-soil grout-water glass double-liquid grout mainly affects durability. If the surrounding environment is highly corrosive, the value can be appropriately increased. The value is between 0.3 and 0.4; other coefficients are between 0.15 and 0.25.

[0095] S53. Perform dimensionless conversion on the economic indicators and corresponding extreme values ​​of each group of target factors to obtain the economic index of cement-soil slurry-water glass dual-liquid slurry; the calculation formula is:

[0096] ;

[0097] In the formula, The economic indicator for cement-soil grout-water glass two-component grout is... For the i-th group of target factors Calculation results The ratio of the combined costs of simultaneous grouting and waste mud treatment to savings; For all combinations The maximum and minimum values ​​of the calculation results.

[0098] S54. Using the fitting formula, calculate the deviation of each performance index when each target factor simultaneously fluctuates positively (i.e., the four target factors are simultaneously added to their respective fluctuation amplitudes) and negatively (i.e., the four target factors are simultaneously subtracted from their respective fluctuation amplitudes) under the preset fluctuation amplitude. Based on the deviation, determine the sensitivity of each performance index to construction disturbance. After performing a reverse dimensionless conversion on the sensitivity, sum the values ​​according to the preset performance weights to obtain the comprehensive anti-interference ability measurement index of the cement-soil slurry-water glass dual-liquid slurry performance index.

[0099] Specifically, the deviation of each performance index is calculated using a fitting formula when each target factor simultaneously fluctuates positively and negatively within a preset fluctuation amplitude. Based on the deviation, the sensitivity of each performance index to construction disturbance is determined. After inverse dimensionless conversion of the sensitivity, it is weighted and summed according to preset performance weights to obtain a comprehensive anti-interference ability index for the performance indicators of cement-soil slurry-water glass dual-liquid slurry, including:

[0100] 1) Calculate the original fitted values ​​of the target factor combination on each performance index according to the fitting formula of each performance index;

[0101] 2) Based on the fitting formulas for each performance index, and combined with the target factors and their corresponding preset fluctuation amplitudes, calculate the fitting values ​​of each performance index under positive and negative fluctuations. Specifically, add the corresponding preset fluctuation amplitudes to the four target factors—slurry specific gravity, water-cement ratio, retarder dosage, and alkali-cement ratio—to calculate the fitting values ​​of each performance index under positive fluctuations. Subtract the corresponding preset fluctuation amplitudes from the four target factors to calculate the fitting values ​​of each performance index under negative fluctuations. The calculation formulas are as follows:

[0102] ;

[0103] ;

[0104] ;

[0105] ;

[0106] ;

[0107] ;

[0108] ;

[0109] ;

[0110] In the formula, , These are the fitted values ​​of the 3-hour bleeding rate of cement-soil slurry under positive and negative fluctuations, respectively, for the i-th group of target factor combinations. , , respectively, are the fitted values ​​of the gelation time of the cement-soil mixture and water glass under positive and negative fluctuations for the i-th group of target factor combinations. , Let be the fitted values ​​of the 1-day unconfined compressive strength under the positive and negative fluctuations, respectively, for the i-th group of target factor combinations. , These are the fitted values ​​of the 28-day unconfined compressive strength under positive and negative fluctuations, respectively, for the i-th group of target factor combinations. These correspond to the values ​​of mud specific gravity, water-cement ratio, retarder dosage, and alkali-cement ratio in the i-th group of target factor combinations, respectively. These represent the fluctuation amplitudes of mud specific gravity, water-cement ratio, retarder dosage, and alkali-cement ratio, respectively. Values ​​greater than 0 are used in this embodiment. The values ​​are respectively 0.05, 0.1%, 0.02. The above positive fluctuations refer to the simultaneous addition of their respective fluctuation amplitudes to the four target factors, while negative fluctuations refer to the simultaneous subtraction of their respective fluctuation amplitudes from the four target factors, in order to simulate the most unfavorable working condition in which all parameters simultaneously deviate in the same direction during construction.

[0111] 3) Calculate the rate of change of the positively fluctuating fitted value relative to the original fitted value and the rate of change of the negatively fluctuating fitted value relative to the original fitted value (i.e., calculate the absolute value of the relative rate of change of the positively fluctuating fitted value relative to the original fitted value and the absolute value of the relative rate of change of the negatively fluctuating fitted value relative to the original fitted value), and use the larger rate of change in the calculation results as the sensitivity value of the performance index to the fluctuation of the target factor; the calculation formula is:

[0112] ;

[0113] ;

[0114] ;

[0115] ;

[0116] In the formula, These represent the variation ranges of the following parameters when the target factors in the i-th group fluctuate: 3-hour bleeding rate of cement slurry, gel time after mixing cement slurry and water glass, 1-day unconfined compressive strength, and 28-day unconfined compressive strength. These are the sensitivity values ​​of the performance indicators to fluctuations in the target factors.

[0117] 4) Perform reverse dimensionless conversion on the sensitivity values ​​of performance indicators to fluctuations of target factors to obtain the individual scores of anti-interference ability for each performance indicator, and combine them with preset performance weights to perform weighted summation, and use the summation result as the comprehensive anti-interference ability measurement index of the performance indicators.

[0118] Specifically, the sensitivity values ​​of performance indicators to fluctuations in target factors are converted into dimensionless values ​​in reverse to obtain individual scores for the anti-interference ability of each performance indicator, including:

[0119] The difference between the maximum sensitivity value and the minimum sensitivity value of each performance index in the target factor combination to the fluctuation of the target factor is used as the score for the anti-interference ability of each performance index. The calculation formula is:

[0120] ;

[0121] ;

[0122] ;

[0123] ;

[0124] In the formula, These are the anti-interference ability indexes for the 3-hour bleeding rate of cement-soil slurry, the gelation time of cement-soil slurry mixed with water glass, the 1-day unconfined compressive strength, and the 28-day unconfined compressive strength under the i-th group of target factor combinations. The values ​​range from 0 to 1. In this embodiment, the anti-interference ability index is used as the individual score for anti-interference ability. These represent the maximum and minimum values ​​of the 3-hour bleeding rate of the cement-soil slurry for all combinations. These represent the maximum and minimum gel times for the mixture of cement slurry and water glass in all combinations. These represent the maximum and minimum values ​​of the 1-day unconfined compressive strength for all combinations. These represent the maximum and minimum values ​​of the 28-day unconfined compressive strength for all combinations.

[0125] The formula for calculating the comprehensive anti-interference ability index of cement-soil grout-water glass two-component grout is as follows:

[0126] ;

[0127] In the formula, It is a comprehensive anti-interference ability index for the performance indicators of cement-soil slurry-water glass dual-liquid slurry.

[0128] S55. Based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil grout-water glass double liquid grout, the comprehensive evaluation index of each target factor combination is obtained by weighting and summing the indexes according to the preset index weights.

[0129] Specifically, the formula for calculating the comprehensive evaluation index is as follows:

[0130] ;

[0131] In the formula, i represents the sequence number of the target factor combination. If there are n combinations in the target factor combination set in S4, then the value of i ranges from 1 to n. is the comprehensive evaluation index for the i-th group of target factors; The comprehensive performance index of the cement-soil slurry-water glass dual-liquid slurry for the i-th group of target factors is used to measure its performance. The economic index for the i-th group of target factors combination of cement-soil slurry-water glass double liquid slurry is used to measure its value. This is the comprehensive anti-interference capability index for performance indicators under the i-th group of target factor combinations; They are respectively The weighting coefficients, .

[0132] The values ​​are all between 0 and 1. The larger the value, the better the overall evaluation, the better the performance of the cement-soil slurry-water glass dual-liquid slurry, the better the economy, and the stronger the resistance to the interference of target factor fluctuations.

[0133] Since S3 has already selected combinations that meet the construction requirements, then regardless of... Regardless of the value chosen, the minimum performance requirements can be met. The value should be determined by comprehensively considering factors such as the hydrogeological conditions of the tunnel location, the surrounding environment, cost control needs, and the level of construction technology. Since different projects have different requirements, the mix proportion can be adjusted accordingly. For high performance requirements, increase the proportion of performance; for high cost control requirements, increase the proportion of economic indicators; for large errors in raw materials or processes, increase the proportion of anti-interference.

[0134] The principle is as follows: Unless there are special circumstances (i.e., the tunnel shield grouting construction is under normal operating conditions), a balanced approach is taken, with each factor representing 1 / 3. If the project is located in an area with high groundwater flow velocity (velocity greater than...), ... For environments with corrosive conditions such as seawater (i.e., groundwater corrosivity exceeding preset levels), or where segment uplift control requirements are high (uplift within 3mm) (i.e., segment uplift control level reaches preset levels), or where the tunnel is located in an area with high environmental protection requirements, α should be appropriately increased to 0.4~0.5 to improve synchronous grouting performance; if there is a strong demand for construction cost control (when the construction cost budget is lower than the preset cost threshold), then β should be taken as 0.4~0.5; if the quality of raw materials is unstable or the weighing error is large during the grouting process (the raw material measurement error exceeds the preset allowable range), then γ should be appropriately increased to 0.4~0.5; the remaining coefficients should be taken between 0.2 and 0.3.

[0135] S6. Determine the optimal combination of target factors based on the calculation results of the comprehensive evaluation index. Based on the values ​​of the target factors in the optimal combination of target factors, determine the quality of mud, cement, retarder and water glass, and obtain the mix ratio of waste mud synchronous two-liquid slurry.

[0136] The optimal combination of target factors is determined based on the calculation results of the comprehensive evaluation index. Based on the values ​​of the target factors in the optimal combination, the quality of mud, cement, retarder, and water glass is determined, resulting in the mix proportion of the waste mud for simultaneous two-liquid slurry production.

[0137] S61. Based on the calculation results of the comprehensive evaluation index of each target factor combination in the target factor combination set, select the target factor combination with the largest comprehensive evaluation index as the optimal target factor combination.

[0138] S62. Determine the mud specific gravity, water-cement ratio, retarder dosage, and alkali-cement ratio based on the optimal combination of target factors, and verify the setting time of cement-soil slurry in the optimal combination of target factors. If the setting time does not meet the preset time threshold, adjust the determined retarder dosage.

[0139] Specifically, because the setting time of cement slurry is very long, it is difficult to measure the precise setting time. Therefore, it is sufficient to verify that the setting time of the optimal combination exceeds 72 hours. If the setting time does not reach 72 hours, the dosage of retarder can be appropriately increased until the requirement is met. According to the tests conducted, the dosage of retarder has a relatively small impact on other performance indicators; therefore, appropriate adjustments will not have a significant effect.

[0140] In this embodiment, the gel time is the time from the start of mixing liquid A and liquid B until they lose their fluidity, and the solidification time is the time from the start of mixing liquid A and liquid B until they solidify and harden.

[0141] S63. Based on the determined mud specific gravity, water-cement ratio, alkali-cement ratio and adjusted retarder dosage, combined with the pre-determined mass of soil particles and water in the mud, calculate the mass of mud, cement, retarder and water glass to be added, and obtain the mix proportion of waste mud synchronous two-liquid slurry.

[0142] Specifically, when calculating the mass, it is necessary to test the water content of the mud at different specific gravities in advance, so as to calculate the mass of soil particles and water in the mud, which is used to estimate the mass of cement, retarder and water glass (that is, the mass of water in the mud is obtained by the water content and the mass of the mud, the corresponding mass of cement is obtained according to the water-cement ratio, and the corresponding mass of retarder and water glass is obtained according to the retarder dosage and alkali-cement ratio respectively).

[0143] Example 2

[0144] A waste mud synchronous dual-liquid slurry, using shield tunneling mud as the main raw material, comprises two parts: cement-soil slurry and water glass, with cement-soil slurry replacing conventional cement slurry.

[0145] The essential components of cement-soil slurry are mud, cement, and retarder. Specifically, the mud is the excavation mud obtained by separating the slag-carrying mud generated during slurry-water balance shield tunneling. This mud simultaneously meets the requirements of shield tunneling and the preparation of synchronous dual-liquid slurry. Based on construction experience and test results, the proportion of particles larger than 100μm in the mud should not exceed 5%.

[0146] The selection of cement, retarder, and water glass is the same as that for ordinary cement-water glass two-liquid slurry. Ordinary Portland cement with a strength of 42.5 MPa can be used as cement. Common types of hydroxycarboxylic acids and their salts, sugar compounds, etc., can be used as retarder. The water glass can be selected according to the current "Industrial Sodium Silicate" (GB / T 4209) type L-280-41.

[0147] Example 3

[0148] A method for preparing a simultaneous two-liquid slurry from waste mud includes:

[0149] 1) Preparation of mud raw materials

[0150] The mud is treated by screening to remove soil and debris carried in the mud, controlling the particle size of soil particles in the mud to ensure that the proportion of particles larger than 100μm does not exceed 5%. The treatment equipment can be selected to sequentially pass through pre-screening, primary hydrocyclone, and secondary hydrocyclone equipment to remove larger soil particles, clods, or impurities, resulting in mud containing smaller particles. The hydrocyclone size, inlet pressure, and inlet flow rate are finalized through commissioning before construction.

[0151] The specific gravity of the mud is controlled during the mud conditioning stage. The mud, after being treated by mud-water separation, is pumped from the sedimentation tank into the mud conditioning tank. An appropriate amount of water is added to make the specific gravity of the mud meet the requirements. If necessary, bentonite and admixtures (such as flocculants, carboxymethyl cellulose, quicklime, etc.) can be added according to the tunneling requirements.

[0152] 2) Preparation of cement slurry

[0153] Procedure: Take an appropriate amount of mud and stir it evenly (at 800 rpm to 1000 rpm for no less than 1 minute), then add the retarder according to the mix ratio and stir evenly (at 800 rpm to 1000 rpm for no less than 1 minute), and finally add cement according to the mix ratio determined in Example 1 and stir evenly (at 800 rpm to 1000 rpm for no less than 3 minutes).

[0154] 3) Mixing cement slurry with water glass solution

[0155] The prepared cement slurry and water glass solution were transported to the grouting pipeline for synchronous grouting according to the mixing ratio determined in Example 1. The two slurries were then mixed and injected into the shield tail gap.

[0156] Furthermore, to better understand the above-mentioned technical solution of the present invention, a specific example is provided below:

[0157] I. Synchronous dual-liquid slurry material with shield tunneling mud as the main raw material.

[0158] The cement-soil grout-water glass two-component grout consists of two parts: cement-soil grout and water glass.

[0159] Cement-soil slurry consists of mud, cement, and a retarder. The mud used is from shield tunneling. Particle size distribution testing shows that particles larger than 100μm account for approximately 3% to no more than 5%. Figure 2 As shown. The cement used is ordinary Portland cement with a strength of 42.5 MPa. The retarder is a product of a certain company used in the project. The water glass is a product of a certain company used in the project, with a modulus of 3.1 and a Baume degree of 40.

[0160] II. Comprehensive Optimization Method for the Mix Proportion of Simultaneous Two-Liquid Slurry in Waste Mud

[0161] Step 1: Using mud specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio as target factors, and setting no less than three levels for each factor, conduct orthogonal experiments to test the performance indicators of cement-soil slurry-water glass two-liquid slurry and calculate the economic indicators (i.e., conduct performance testing experiments and calculate economic indicators).

[0162] Four levels were set with mud specific gravity, water-cement ratio, retarder dosage, and alkali-cement ratio as target factors, as shown in Table 1.

[0163] Table 1. Factors and levels in orthogonal experiments

[0164] The levels of the above factors are not fixed, but the values ​​in the table above cover the commonly used range in engineering and are of strong reference value.

[0165] The test results of the performance indicators and the calculation results of the economic indicators of the cement-soil grout-water glass two-component grout are shown in Table 2.

[0166] Table 2. List of Orthogonal Experiments and Results

[0167] The cost savings ratio is calculated as follows: when injecting the same volume of synchronous grout, the cost of using the synchronous two-component grout material invented in this invention, minus the reduced waste mud treatment cost, is the cost savings compared to using conventional cement-water glass two-component grout. Based on actual project prices: cement 342 yuan / t, retarder 3.87 yuan / kg, bentonite 760 yuan / t, tap water 5.29 yuan / t, water glass 800 yuan / t, and mud treatment cost... Taking number 2 as an example, the specific gravity of the mud... The water content in the mud was measured to be 85.5%, meaning that 1000 kg of mud contains 855 kg of water. Based on a water-cement ratio of 2.9, a retarder dosage of 0.4%, and an alkali-cement ratio of 0.35, it can be calculated that 294.81 kg of cement and 1.18 kg of retarder are added to every 1000 kg of mud, corresponding to 103.18 kg of water glass. The specific gravity of the cement-soil slurry obtained by mixing mud, cement, and retarder is... Therefore, the volume of the cement-soil slurry obtained from the above quality is The specific gravity of the water glass used is Therefore, the volume of water glass is That is, the volume of the cement-soil slurry-water glass two-component slurry is Based on the above unit price, it can be calculated that... The cost of the grouting material (cement, retarder, and water glass only) is 187.94 yuan. The calculated savings in grout treatment costs are 63.64 yuan. Therefore, The comprehensive cost of the grouting body is 124.30 yuan, so the cost per cubic meter is 116.34 yuan. The conventional cement-water glass two-liquid grout used in the project, composed of cement, retarder, bentonite, tap water, and water glass, contains 280 kg of cement, 2.8 kg of retarder, 30 kg of bentonite, 830 kg of tap water, and 105.4 kg of water glass per cubic meter of grouting body, resulting in a calculated cost of 218.11 yuan per cubic meter. Therefore, mix designation 2 saves 46.7% of the comprehensive cost. The remaining mix designs are calculated using the same method.

[0168] Furthermore, since price systems vary across different regions and projects, the economic indicators in this embodiment can be recalculated and fitted based on the price parameters of different projects to enhance the versatility of the method.

[0169] Step 2: Perform multiple regression fitting on the orthogonal test results to obtain the fitting formulas of the performance index and economic index of cement-soil slurry-water glass dual-liquid slurry with respect to the target factors (i.e., fitting the performance index and economic index calculation formulas).

[0170] The results in Table 2 were fitted using SPSS software, and the fitting formula is as follows:

[0171] ;

[0172] ; ;

[0173] ;

[0174] ;

[0175] In the formula, The water bleeding rate of cement-soil slurry after 3 hours; The gelation time of the mixture of cement slurry and water glass is expressed in seconds. The unconfined compressive strength over 1 day is expressed in MPa. The unconfined compressive strength at 28 days is expressed in MPa. The ratio of the combined costs of simultaneous grouting and waste mud treatment to savings; This refers to the specific gravity of the mud, in units of... ; This refers to the water-to-binder ratio; This refers to the dosage of retarder; This refers to the alkali-to-gum ratio.

[0176] The above The coefficient of determination of the fitting formula The values ​​are 0.968, 0.977, 0.987, 0.950, and 0.933, respectively, indicating an excellent fit and that the formula almost perfectly replicates the data patterns.

[0177] Step 3: Based on industry standards and project grouting requirements, determine the range of values ​​for the performance indicators of cement-soil grout-water glass dual-liquid grout, and based on the geological conditions, determine the range of values ​​for the mud slurry specific gravity (i.e., determine the range of values ​​for the performance indicators and the mud slurry specific gravity).

[0178] Condition 1: Generally, the bleeding rate of cement-soil grout within 3 hours should be controlled to not exceed 5%; if the project uses an 8m long grouting pipeline, the gel time after mixing the cement-soil grout with water glass should be controlled between 15s and 21s; the unconfined compressive strength at 1 day and 28 days should not be less than 0.2MPa and 1.0MPa respectively, therefore, The constraints can be determined using the fitting formula.

[0179] ;

[0180] At this point, if the tunnel boring machine is located in a clay stratum, it is limited .

[0181] Condition 2: Based on the project characteristics, the requirements for some indicators are appropriately increased, such as a bleeding rate not exceeding 3% and an unconfined compressive strength of not less than 0.5 MPa per day. The constraints can be determined using the fitting formula.

[0182] ;

[0183] At this point, if the tunnel boring machine is located in a permeable sand layer, it is limited .

[0184] Step 4: Using the value range of Step 3 as a constraint, solve for all the target factor combinations that meet the synchronous grouting performance index and tunneling mud requirements according to the fitting formula of Step 2 (i.e., solve for the target factor combinations that meet the performance requirements).

[0185] Solve the problem using Excel based on the constraints in step 3, and limit the range of performance indicators. And considering the limitations of the requirements for mud during shield tunneling. The range of values ​​is used to solve for the combination set of target factors: mud specific gravity, water-cement ratio, retarder dosage, and alkali-cement ratio.

[0186] When using Excel for iterative calculations and solutions, code can be written to achieve this (see...). Figure 3 ), The step size is set to 0.01. The step size can be 0.1. The step size can be 0.1%. The step size can be 0.01.

[0187] When operating under condition 1, the mud specific gravity is set according to the clay stratum. This yields 1083 sets of target factor combinations that meet the requirements. Some of these target factor combinations, along with their performance and economic indicators, are listed in Table 3.

[0188] Table 3 Target Factor Combination Set 1

[0189] When operating under condition 2, the mud specific gravity is set according to the permeable sand layer. This yields 7316 sets of target factor combinations that meet the requirements. Some of these target factor combinations, along with their performance and economic indicators, are listed in Table 4.

[0190] Table 4 Target Factor Combination Set 2

[0191] Step 5: Establish a comprehensive evaluation index that considers performance indicators, economic indicators and reliability. Select the combination with the largest comprehensive evaluation index from the set of target factor combinations obtained in Step 4 (i.e., establish and calculate the comprehensive evaluation index of each combination to obtain the optimal combination).

[0192] For the target factor combination set 1 in Table 3:

[0193] There are 1083 combinations in total. First, find the results from the first 1083 combinations. , , , , The results are shown in Table 5. Then, the calculations for each group were performed. Results, and each group Results. Assuming the slurry needs to be stored for a long time and the control of segment float is extremely stringent, The values ​​were 0.3, 0.4, 0.15, and 0.15, and the results for each group were calculated. result.

[0194] Table 5 Extreme values ​​of target factor combination set 1

[0195] Next, set They are respectively 0.05, 0.1%, 0.02, calculated to obtain , Then calculate to get and the calculated And so on, the calculation yields... Then calculate to get result.

[0196] Based on the above conditions, and considering the strong need for construction cost control while maintaining a high level of construction technology to ensure stable control of target factors, values ​​of α, β, and γ are set to 0.3, 0.5, and 0.2, respectively. Finally, the calculations yield... Results: The largest value among the 1083 groups was selected. The result was 0.576, as shown in Table 6. The corresponding target factor combination was mud specific gravity. The optimal combination is a water-cement ratio of 3.1, a retarder dosage of 0, and an alkali-cement ratio of 0.38. It can be seen that the economic indicator index C value is relatively high, and the overall cost saving ratio is 0.518, which means a further reduction of 51.8% in expenses compared to the current cost.

[0197] Table 6 Optimal Combination 1

[0198] For the target factor combination set 2 in Table 4:

[0199] There are 7316 combinations in total. From the results of combinations 1 to 7316, first find... , , , , The results are shown in Table 7. Then, the calculations for each group were performed. Results, and each group Result. Assuming no special circumstances, The values ​​are all 1 / 4, and the calculations for each group are as follows. result.

[0200] Table 7 Extreme values ​​of the target factor combination set 2

[0201] Next, set They are respectively 0.05, 0.1%, 0.02, calculated to obtain , Then calculate to get and the calculated And so on, the calculation yields... Then calculate to get result.

[0202] Based on the above conditions, assuming a high groundwater ion concentration environment, high performance requirements such as strength, and due to insufficient precision in controlling the target factors, it is necessary to improve the resistance to fluctuations in these factors. This can reduce economic requirements, so values ​​of α, β, and γ are set to 0.4, 0.2, and 0.4, respectively. Finally, the calculations yield... Results: The largest value among 7316 groups was selected. The result was 0.592, as shown in Table 8. The corresponding target factor combination was mud specific gravity. The optimal combination is defined as follows: water-cement ratio 2.6, retarder dosage 0, and alkali-cement ratio 0.52. It can be seen that the specimens with this combination exhibit very high strength, far exceeding that of conventional cement-water glass grout, and a very low bleeding rate. Furthermore, the overall performance index R-value, which measures resistance to interference, is high, indicating better long-term service performance in corrosive environments and reduced impact from fluctuations in target factors.

[0203] Table 8 Optimal Combination 2

[0204] Step 6: Verify the setting time. If the setting time does not meet the construction requirements, increase the amount of retarder appropriately (i.e., verify the setting time and adjust the amount of retarder as needed).

[0205] Since the retarder dosage in the optimal mix proportion is 0%, the cement slurry setting time is less than 72 hours, which does not meet the construction requirements. After increasing the retarder dosage to 1%, the setting time exceeds 72 hours. Therefore, the final retarder dosage is 1%.

[0206] By determining the specific gravity of the mud, the water-cement ratio, the dosage of the retarder, and the alkali-cement ratio, the mass of the added mud, cement, retarder, and water glass is calculated, thus obtaining the mix proportion.

[0207] To calculate the mass, it is necessary to test the water content of the mud at different specific gravities in advance, so as to calculate the mass of soil particles and water in the mud, which is then used to estimate the mass of cement, retarder and water glass.

[0208] For specific gravity for The mud slurry was measured to have a water content (the proportion of water to mud mass) of 80.8%, indicating that 100 kg of mud slurry contains 19.2 kg of soil particles and 80.8 kg of water. Next, based on the water-cement ratio... =3.1, resulting in a cement mass of 26.06 kg. Based on the retarder dosage... =1%, yielding a retarder mass of 0.26 kg, based on the alkali-to-binder ratio. =0.38, yielding a water glass mass of 9.90 kg. Therefore, mix proportion 1 consists of 100 kg of mud, 26.06 kg of cement, 0.26 kg of retarder, and 9.90 kg of water glass. The mud accounts for 79.2% of the cement-soil slurry mass and 73.4% of the total mass of the two-component slurry.

[0209] For specific gravity for The mud slurry was measured to have a water content of 73.4% (the proportion of water to mud mass), indicating that 100 kg of mud slurry contains 26.6 kg of soil particles and 73.4 kg of water. Next, based on the water-cement ratio... =2.6, yielding a cement mass of 28.23 kg. Based on the retarder dosage... =1%, yielding a retarder mass of 0.28 kg, based on the alkali-to-binder ratio. =0.52, yielding a water glass mass of 14.68 kg. Therefore, mix proportion 2 is 100 kg of mud, 28.23 kg of cement, 0.28 kg of retarder, and 14.68 kg of water glass. The mud accounts for 77.8% of the cement-soil slurry mass and 69.8% of the total mass of the two-component slurry.

[0210] III. Preparation method of simultaneous two-liquid slurry for waste mud

[0211] (1) Preparation of mud raw materials

[0212] After preliminary screening ( Figure 4 ) and first- and second-order vortices ( Figure 5 The mud in the discharge pipe is treated. The particle size distribution of the treated mud is as follows: Figure 2 The proportion of particles larger than 100μm does not exceed 5%. The resulting slurry enters a sedimentation tank, see... Figure 6 When preparing the mud slurry, the mud slurry in the sedimentation tank is pumped to the mixing tank. Water is added to adjust the mud slurry specific gravity to the optimal combination, thus obtaining the raw material for the mud slurry. (See...) Figure 7 .

[0213] (2) Preparation of cement slurry

[0214] When preparing mix proportions 1 and 2, the raw materials are added in proportion and order according to the mass of the mud, retarder, and cement obtained above. First, add an appropriate amount of mud and stir at 900 rpm for 1 minute. Then, add the retarder according to the mass proportion and continue stirring at the same speed for 1 minute. Finally, add the cement according to the mass proportion and stir at the same speed for 3 minutes to obtain cement-soil slurry.

[0215] (3) Mixing cement slurry with water glass solution

[0216] The prepared cement slurry and water glass solution are transported separately to the grouting pipeline for synchronous grouting according to the mass ratio. The two slurries are then mixed and injected into the shield tail gap.

[0217] Comparing the obtained grouting bodies, after being placed in the environment for the same period of time, from Figure 8 (The two basins above are cement-water glass double-liquid slurry, and the one below is cement-soil slurry-water glass double-liquid slurry.) It can be seen that the cement-soil slurry-water glass double-liquid slurry structure in this invention is still dense, while the cement-water glass double-liquid slurry has lost water and cracked. It can be seen that the slurry of this invention has better durability.

[0218] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for comprehensively optimizing the mix proportion of waste mud using a simultaneous two-liquid slurry method, characterized in that, include: Based on the target factors, the performance indicators of cement-soil slurry-water glass two-liquid slurry were tested by orthogonal experiment, and the economic indicators were determined. The target factors were slurry specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio. Multiple regression fitting was performed on the orthogonal test results to obtain the fitting formulas for the performance and economic indicators of cement-soil grout-water glass double liquid grout with respect to the target factors. Based on industry standards and project grouting requirements, the range of values ​​for the performance indicators of cement-soil grout-water glass dual-liquid grout was determined, and the range of values ​​for the grout specific gravity was determined based on the geological characteristics. Using the range of performance indicators and mud specific gravity as constraints, and combining the fitting formula, we solve for all the target factor combinations that meet the performance indicators of synchronous grouting and the requirements of tunneling mud. Based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, calculate the comprehensive evaluation index of each target factor combination in the target factor combination set. The optimal combination of target factors is determined based on the calculation results of the comprehensive evaluation index. Based on the values ​​of the target factors in the optimal combination of target factors, the quality of mud, cement, retarder and water glass is determined, and the mix proportion of waste mud synchronous two-liquid slurry is obtained.

2. The method for comprehensive optimization of the proportion of simultaneous two-liquid slurry in waste mud according to claim 1, characterized in that, The cement-soil slurry includes mud, cement and retarder, and the mud is the excavation mud obtained by separating the slag-carrying mud generated by the mud-water balance shield tunneling and then re-obtaining it, and the proportion of particles with a diameter greater than 100μm in the excavation mud is less than or equal to 5%.

3. The method for comprehensive optimization of the proportion of simultaneous two-liquid slurry in waste mud according to claim 1, characterized in that, Economic indicators are determined based on the combined cost savings from simultaneous grouting and waste mud treatment. The performance indicators of the cement-soil slurry-water glass two-component slurry include: the 3-hour bleeding rate of the cement-soil slurry, the gel time after mixing the cement-soil slurry and water glass, the 1-day unconfined compressive strength, and the 28-day unconfined compressive strength.

4. The method for comprehensive optimization of the proportion of simultaneous two-liquid slurry in waste mud according to claim 1, characterized in that, When fitting multiple regressions, if the coefficient of determination is greater than or equal to a preset threshold, a multiple linear polynomial is used for fitting; if the coefficient of determination is less than the preset threshold, a multiple nonlinear quadratic polynomial is used for fitting.

5. The method for comprehensively optimizing the mix proportion of simultaneous two-liquid slurry in waste mud according to claim 1, characterized in that, The comprehensive performance index, economic index, and comprehensive anti-interference ability index of the cement-soil slurry-water glass dual-liquid slurry are used to calculate the comprehensive evaluation index of each target factor combination in the target factor combination set, including: Based on the target factor combination set obtained by the solution, the extreme values ​​of the range of each performance index and economic index are determined, and the fluctuation values ​​of mud specific gravity, water-cement ratio, retarder dosage and alkali-cement ratio during the construction process are determined. Each performance index in each group of target factors is converted to the corresponding extreme value of the range without dimension, and the performance index of each performance index in the target factor combination is determined. The comprehensive performance index of cement-soil slurry-water glass double liquid slurry is obtained by weighted summation in combination with preset performance weights. The economic indicators and their corresponding extreme values ​​in each group of target factors are converted into dimensionless values ​​to obtain the economic index of cement-soil slurry-water glass double liquid slurry. The deviation of each performance index is calculated by using the fitting formula when each target factor fluctuates positively and negatively at the preset fluctuation amplitude. The sensitivity of each performance index to construction disturbance is determined based on the deviation. After the sensitivity is converted into a dimensionless value in reverse, it is weighted and summed according to the preset performance weight to obtain the comprehensive anti-interference ability index of the cement-soil slurry-water glass dual liquid slurry. Based on the comprehensive performance index, economic index, and comprehensive anti-interference ability index of cement-soil slurry-water glass dual-liquid slurry, the comprehensive evaluation index of each target factor combination is obtained by weighting and summing the indexes according to the preset index weights.

6. The method for comprehensive optimization of the proportion of simultaneous two-liquid slurry in waste mud according to claim 5, characterized in that, The determination of the performance index's merit score within the target factor combination includes: The score for the 3-hour bleeding rate of cement slurry is determined by dividing the difference between the maximum and minimum bleeding rates in the target factor combination by the difference between the maximum and minimum bleeding rates. The quality score of the gel time of the cement slurry mixed with water glass is determined by dividing the smaller of the distance from the minimum gel time and the distance from the maximum gel time in the target factor combination by the average of the minimum gel time and the maximum gel time. The score for the 1d unconfined compressive strength is determined by dividing the difference between the strength value and the minimum strength value in the target factor combination by the difference between the maximum strength value and the minimum strength value. The score for the 28-day unconfined compressive strength is determined by dividing the difference between the strength value and the minimum strength value in the target factor combination by the difference between the maximum strength value and the minimum strength value.

7. The method for comprehensive optimization of the proportion of simultaneous two-liquid slurry in waste mud according to claim 5, characterized in that, The process involves using a fitting formula to calculate the deviation of each performance index when each target factor simultaneously fluctuates positively and negatively within a preset fluctuation amplitude. Based on the deviation, the sensitivity of each performance index to construction disturbances is determined. After inverse dimensionless conversion of the sensitivity, a weighted sum is calculated according to preset performance weights to obtain a comprehensive anti-interference capability index for the performance indicators of the cement-soil slurry-water glass dual-liquid slurry, including: Based on the fitting formulas for each performance index, calculate the original fitted values ​​of the target factor combination on each performance index; Based on the fitting formulas of each performance index, combined with the target factors and their corresponding preset fluctuation amplitudes, the fitting values ​​of each performance index under positive and negative fluctuations are calculated. Calculate the rate of change of the fitted value with positive fluctuation relative to the original fitted value and the rate of change of the fitted value with negative fluctuation relative to the original fitted value, and take the larger rate of change in the calculation results as the sensitivity value of the performance index to the fluctuation of the target factor. The sensitivity values ​​of performance indicators to fluctuations in target factors are converted into dimensionless values ​​in reverse to obtain the individual scores of anti-interference ability for each performance indicator. These scores are then combined with preset performance weights and summed. The summation result is used as the comprehensive anti-interference ability index of the performance indicators.

8. The method for comprehensive optimization of the mix proportion of simultaneous two-liquid slurry in waste mud according to claim 7, characterized in that, The sensitivity values ​​of performance indicators to fluctuations in target factors are converted into dimensionless values ​​in reverse to obtain individual scores for the anti-interference ability of each performance indicator, including: The difference between the maximum sensitivity of each performance index to the fluctuation of the target factor and the sensitivity value is divided by the difference between the maximum and minimum sensitivity values. The result is used as the individual score for the anti-interference ability of each performance index.

9. The method for comprehensively optimizing the mix proportion of simultaneous two-liquid slurry in waste mud according to claim 1, characterized in that, The determination of the index weights for the comprehensive performance index, the economic index, and the comprehensive anti-interference capability index includes: When the tunnel shield synchronous grouting construction is under normal working conditions, the three are equal; When the groundwater corrosivity index exceeds the preset index or the segment uplift control level reaches the preset level, the weight of the comprehensive performance index is greater than the other two. When the construction cost budget is lower than the preset cost threshold, the weight of the economic indicator measurement index is greater than the other two. When the measurement error of raw materials exceeds the preset allowable range, the weight of the comprehensive anti-interference ability measurement index of performance indicators is greater than the other two.

10. The method for comprehensive optimization of the proportion of simultaneous two-liquid slurry in waste mud according to claim 1, characterized in that, The optimal combination of target factors is determined based on the calculation results of the comprehensive evaluation index. Based on the values ​​of the target factors in the optimal combination, the quality of mud, cement, retarder, and water glass is determined to obtain the mix proportion of the waste mud for simultaneous two-liquid slurry production, including: Based on the calculation results of the comprehensive evaluation index of each target factor combination in the target factor combination set, the target factor combination with the largest comprehensive evaluation index is selected as the optimal target factor combination. The specific gravity of the mud, the water-cement ratio, the dosage of retarder and the alkali-cement ratio are determined based on the optimal combination of target factors. The setting time of the cement-soil slurry in the optimal combination of target factors is verified. When the setting time does not meet the preset time threshold, the determined dosage of retarder is adjusted. Based on the determined mud specific gravity, water-cement ratio, alkali-cement ratio, and adjusted retarder dosage, combined with the pre-determined mass of soil particles and water in the mud, the mass of mud, cement, retarder, and water glass to be added is calculated, and the mix proportion of waste mud synchronous two-liquid slurry is obtained.

Images