Full-stratum shield muck adaptability dynamic improvement method

Abstract

The application discloses a kind of full stratum shield muck adaptability dynamic modification method, and the application belongs to the field of shield construction technology, comprising: obtaining the stratum hydrological condition of full stratum shield muck, based on stratum hydrological condition, stratum is classified, obtains several stratum classification results;Based on the stratum characteristics corresponding to several stratum classification results, different characteristic parameters are selected as several improvement scheme indexes, based on several improvement scheme indexes, set up several stratum improvement schemes;Set up the improvement scheme index threshold value corresponding to stratum classification result;Obtain the characteristic parameter value of stratum classification result, based on improvement scheme index threshold value, the characteristic parameter value is judged, based on the result of judgment, obtain the optimal stratum improvement scheme.The application avoids the problem that selection standard is not clear in traditional improvement scheme, and the adaptability to complex and changeable engineering geology hydrological condition is poor.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of shield construction process, and particularly relates to a full-stratum shield muck adaptability dynamic improvement method. BACKGROUND

[0002] Shield construction is widely used in domestic rail transit construction due to its safety, high efficiency and wide adaptability. During shield construction, due to different stratum conditions, mud cake of cutter head in high cohesive stratum, gushing in water-rich stratum, and cutter wear in high abrasion stratum may affect construction progress.

[0003] In order to improve the stratum adaptability of the shield and ensure the sustainable construction of the shield, the shield muck is often improved so as to have good fluidity, appropriate plasticity, low shear strength and adhesion strength, small permeability coefficient and certain compressibility. The traditional improvement system mainly determines the improvement scheme according to the stratum information through experience, but this improvement system has certain limitations, the selection standard is not clear, and the adaptability to complex and variable engineering geological and hydrological conditions is poor. SUMMARY

[0004] The application provides a full-stratum shield muck adaptability dynamic improvement method to solve the technical problems in the prior art.

[0005] To achieve the above purpose, the application provides a full-stratum shield muck adaptability dynamic improvement method, which comprises the following steps:

[0006] Obtaining stratum hydrological conditions of full-stratum shield muck, classifying stratum based on the stratum hydrological conditions to obtain a plurality of stratum classification results;

[0007] Based on stratum characteristics corresponding to the plurality of stratum classification results, selecting different characteristic parameters as a plurality of improvement scheme indexes, and setting a plurality of stratum improvement schemes based on the plurality of improvement scheme indexes;

[0008] Setting an improvement scheme index threshold value corresponding to the stratum classification result;

[0009] Obtaining a characteristic parameter value of the stratum classification result, judging the characteristic parameter value based on the improvement scheme index threshold value, and obtaining an optimal stratum improvement scheme based on the judgment result.

[0010] Preferably, the process of obtaining a plurality of stratum classification results comprises the following steps:

[0011] Obtaining geological survey data of a shield construction site, obtaining stratum hydrological conditions based on the geological survey data, and classifying stratum into sandy stratum, cohesive stratum and high abrasion stratum based on the stratum hydrological conditions.

[0012] Preferably, the process of selecting different characteristic parameters as several improvement scheme indicators comprises:

[0013] Based on the formation characteristics of the sandy formation, the formation permeability coefficient is selected as the first improvement scheme indicator;

[0014] Based on the formation characteristics of the cohesive formation, the formation consistency index is selected as the second improvement scheme indicator;

[0015] Based on the formation characteristics of the high abrasion formation, the rock abrasion index is selected as the third improvement scheme indicator.

[0016] Preferably, the process of setting the improvement scheme indicator threshold corresponding to the formation classification result comprises:

[0017] Based on the sandy formation, the first fixed value of the formation permeability coefficient is set as the first improvement scheme indicator threshold;

[0018] Based on the cohesive formation, the second fixed value of the formation consistency index is set as the second improvement scheme indicator threshold;

[0019] Based on the high abrasion formation, the third fixed value of the rock abrasion index is set as the third improvement scheme indicator threshold.

[0020] Preferably, the process of obtaining the optimal formation improvement scheme in the sandy formation comprises:

[0021] Based on the first fixed value of the formation permeability coefficient, the characteristic parameter value is judged;

[0022] If the characteristic parameter value is greater than or equal to the first fixed value, the improvement scheme of mixing bentonite with a gushing prevention agent is selected;

[0023] If the characteristic parameter value is less than the first fixed value, the improvement scheme of mixing non-ionic foaming agent with a gushing prevention agent is selected.

[0024] Preferably, the process of obtaining the optimal formation improvement scheme in the cohesive formation comprises:

[0025] Based on the second fixed value of the formation consistency index, the characteristic parameter value is judged;

[0026] If the characteristic parameter value is less than or equal to the second fixed value, the improvement scheme of non-ionic foaming agent is selected;

[0027] If the characteristic parameter value is greater than the second fixed value, the improvement scheme of mixing high molecular anti-sticking agent with non-ionic foaming agent is selected.

[0028] Preferably, the process of obtaining the optimal formation improvement scheme in the high abrasion formation comprises:

[0029] judging the value of the characteristic parameter based on a third fixed value of the rock abrasion index;

[0030] if the value of the characteristic parameter is less than or equal to the third fixed value, selecting a modified scheme of using a high-molecular wear-resistant agent and a spray-preventing agent in combination;

[0031] if the value of the characteristic parameter is greater than the third fixed value, selecting a modified scheme of using a high-molecular wear-resistant agent, bentonite and a spray-preventing agent in combination.

[0032] Compared with the prior art, the application has the following advantages and technical effects:

[0033] The application provides a full-stratum shield muck adaptability dynamic improvement method, first, obtaining stratum hydrological conditions of full-stratum shield muck, based on the stratum hydrological conditions, classifying the stratum to obtain a stratum classification result; second, based on stratum characteristics of the stratum classification result, selecting a characteristic parameter as an improvement scheme index, based on the improvement scheme index, setting a stratum improvement scheme; at the same time, setting an improvement scheme index threshold corresponding to the stratum classification result; finally, obtaining a value of the characteristic parameter of the stratum classification result, based on the improvement scheme index threshold, judging the value of the characteristic parameter, based on a judgment result, obtaining a stratum improvement scheme. The application classifies the stratum according to corresponding indexes of stratum property characteristics, dynamically selects an improvement scheme according to different property characteristics, and avoids the problems of unclear selection standard and poor adaptability to complex and changeable engineering geology and hydrology conditions in the traditional improvement scheme. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of this application and their description together with the drawings serve to explain the application. In the drawings:

[0035] Fig. 1 A full-stratum shield muck adaptability dynamic improvement method flow chart of the embodiments of the application;

[0036] Fig. 2 A full-stratum shield muck adaptability dynamic improvement schematic diagram of the embodiments of the application. DETAILED DESCRIPTION

[0037] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0038] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0039] Embodiment one

[0040] As Figs. 1-2 shown, the embodiment provides a full stratum shield muck adaptability dynamic improvement method, comprising:

[0041] Obtaining the stratum hydrological condition of the full stratum shield muck, classifying the stratum based on the stratum hydrological condition, and obtaining the stratum classification result;

[0042] Based on the stratum characteristics of the stratum classification result, selecting a characteristic parameter as an improvement scheme index, and setting the stratum improvement scheme based on the improvement scheme index;

[0043] Setting an improvement scheme index threshold corresponding to the stratum classification result;

[0044] Obtaining the characteristic parameter value of the stratum classification result, judging the characteristic parameter value based on the improvement scheme index threshold, and obtaining the stratum improvement scheme based on the judgment result.

[0045] Specifically comprising the following steps:

[0046] (1) Determine the stratum type

[0047] Determine the stratum condition through geological survey of the shield construction site. The determination of the geological hydrological condition classifies the stratum into three categories: sandy stratum, cohesive stratum, and high erosion stratum.

[0048] (2) Determine the index of improvement scheme selection

[0049] Three different strata respectively apply three different indexes to determine the use of the improvement agent. When the earth pressure balance shield tunneling is used in the sandy stratum, the stratum permeability coefficient k is preferably selected as the index of the sandy stratum improvement agent due to the high water pressure and strong permeability of the stratum, which is prone to gushing phenomenon; in the soil layer with high clay mineral content and weathered rock layer, the stratum consistency index I c is preferably selected as the index of the cohesive stratum improvement agent due to the adhesion and recompaction of the cohesive soil, and the clay particles will adhere to the metal surface of the shield machine tool, causing soil bin blockage and cutter mud cake; in the high erosion stratum such as quartz, weathered granite and sand pebble with high content of coarse particles, the rock abrasion index CAI is preferably selected as the index of the high erosion stratum improvement agent due to the serious abrasion of the shield cutter.

[0050] (3) Determine the improvement scheme

[0051] 1) Sand stratum improvement scheme

[0052] Firstly, the sand stratum is divided into intervals according to permeability, and the stratum permeability coefficient k≥10 -3 m / s is an extremely high permeability stratum, and the stratum permeability coefficient k>10 -3 m / s. -5 m / s is a high permeability stratum, and the stratum permeability coefficient k<10 -5 m / s is a general permeability stratum.

[0053] Further, the stratum permeability k of the shield construction site is determined by field measurement method. The test conditions of the field measurement method are more in line with the actual stratum permeability, and the measured permeability coefficient k is the average value of the stratum permeability coefficient in a larger range of the entire seepage area, which is a more reliable measurement method.

[0054] When k≥10 -3 m / s, the sand stratum has high permeability and is prone to gushing, and bentonite and gushing prevention agent are used for improvement of the muck. The bentonite increases the specific gravity of the fine-grained soil in the soil chamber, and a 20% concentration of bentonite is configured, mixed in the bentonite box, and then injected into the cutter head, soil chamber and other parts. Then, 10% concentration of gushing prevention agent is separately injected into the soil chamber and the screw conveyor. In this embodiment, the shield of a certain section of Jinan subway passes through a sand stratum, and there is abundant underground spring water, which is prone to gushing. By using bentonite and gushing prevention agent for improvement, the advancing speed is increased from 10 mm / min to 22 mm / min, and the effect is remarkable.

[0055] When 10 -5 m / s≤k<10 -3 m / s, the sand stratum has high permeability and is prone to gushing, and the gushing prevention agent (0.4-1.0%) and the non-ionic foaming agent (2.0-3.0%) are mixed, foamed by the foaming system, and injected into the cutter head, soil chamber, screw conveyor and other parts for muck improvement.

[0056] When k<10 -5 m / s, the sand stratum has general permeability and generally does not have strong gushing. The gushing prevention agent (0.2-0.4%) and the non-ionic foaming agent (2.0-3.0%) are mixed, foamed by the foaming system, and injected into the cutter head, soil chamber, screw conveyor and other parts for muck improvement.

[0057] 2) Clay stratum improvement scheme

[0058] Firstly, the clay stratum is divided into intervals according to the consistency index I c , and the stratum 0.5<I c ≤0.5 is a soft stratum, and the stratum 0.5<I c≤0.75 is soft ground, ground 0.75 < I c ≤1.0 is hard ground, ground I c >1.0 is hard ground;

[0059] Further, take clay samples of the ground at the shield construction site, use the LP-100 type liquid-plastic limit combined instrument to determine the cone penetration depth of the soil body, and use the combined determination results to determine the natural consistency of the soil;

[0060] When I c ≤0.5, the clayey ground has a low blocking risk, and it is preferred to use a non-ionic foaming agent (2.0-3.0%) to foam through the foaming system, and inject into the cutter head, soil bin, screw conveyor and other parts to improve the spoil.

[0061] When 0.5 < I c ≤0.75, construction in this ground is extremely prone to blocking, which seriously affects the shield tunneling speed, and traditional use of foam and bentonite for spoil improvement cannot solve the problem of mud cake in high clay ground, it is preferred to mix high molecular anti-sticking agent (1.5-2.0%) with non-ionic foaming agent (2.0-3.0%), then foam through the foaming system, and inject into the cutter head, soil bin, screw conveyor and other parts to improve the spoil. It has been successfully applied in the shield engineering of Changchun Metro Line 2 West Extension Line, solving the problem of mud cake and increasing the tunneling speed by 3 times.

[0062] When 0.75 < I c ≤1.0, the clayey ground has a high blocking risk, it is preferred to mix high molecular anti-sticking agent (1.0-1.5%) with non-ionic foaming agent (2.0-3.0%), then foam through the foaming system, and inject into the cutter head, soil bin, screw conveyor and other parts to improve the spoil.

[0063] When I c >1.0, the clayey ground has a medium blocking risk, and the effect of using only a single non-ionic foaming agent for improvement cannot meet the engineering needs, it is preferred to mix high molecular anti-sticking agent (0.5-1.0%) with non-ionic foaming agent (2.0-3.0%), then foam through the foaming system, and inject into the cutter head, soil bin, screw conveyor and other parts to improve the spoil.

[0064] 2) High abrasion ground improvement scheme

[0065] First, divide the high abrasion ground according to the rock abrasion index CAI, ground 0.3 < CAI ≤ 2.0 is a general abrasion ground, ground 2.0 < CAI ≤ 4.0 is a high abrasion ground, and ground 4.0 < CAI is an extremely strong abrasion ground;

[0066] Further, the JHC01 rock mechanics test rock abrasiveness / rock wear index (CAI value) test system detects the abrasiveness of the stratum for shield construction and determines the rock abrasion index of the stratum, and the test finds that the CAI value has a strong correlation with the quartz content, and the greater the CAI value, the higher the quartz content;

[0067] When 0.3≤CAI≤2.0, the stratum abrasiveness is high, and at the same time, it is reflected that the stratum contains a certain amount of medium and fine sand, etc., and the stratum has a certain permeability, and the high polymer wear-resistant agent is mixed with the gushing prevention agent (the ratio of the two is 1:1), then foamed by the foaming system, and injected into the cutter head, the soil bin, the screw conveyor and other parts to improve the muck.

[0068] When 2.0<CAI≤4.0, the stratum abrasiveness is high, and at the same time, it is reflected that the stratum contains a certain amount of coarse sand, gravel, etc., and the stratum has high permeability, and the high polymer wear-resistant agent is used in combination with bentonite, the bentonite increases the specific gravity of the fine clay in the soil bin, a 20% concentration of bentonite is configured, mixed by the bentonite box, and then injected into the cutter head, the soil bin and other parts, and then 8% concentration of high polymer wear-resistant agent and gushing prevention agent are separately injected into the soil bin and the screw conveyor.

[0069] When CAI>4.0, the stratum has strong abrasiveness, and at the same time, it is reflected that the stratum contains a large amount of coarse sand, gravel, etc., and the stratum has strong permeability, and the high polymer wear-resistant agent is used in combination with bentonite, a 20% concentration of bentonite is configured, mixed by the bentonite box, and then injected into the cutter head, the soil bin and other parts, and then 10% concentration of high polymer wear-resistant agent and gushing prevention agent are separately injected into the soil bin and the screw conveyor.

[0070] The embodiment has the following beneficial effects:

[0071] The embodiment discloses a full-stratum shield muck adaptability dynamic improvement system, and the permeability coefficient k, the consistency index I c and the rock abrasion index CAI are respectively used as indexes for selecting a sandiness, clayiness and high abrasiveness stratum improvement scheme, so that the improvement scheme has strong stratum adaptability; three kinds of strata are divided according to corresponding indexes of stratum property characteristics, and improvement schemes are dynamically selected according to different property characteristics.

[0072] The embodiment selects appropriate proportions of improvement materials according to stratum conditions, and avoids the defects of single improvement material, poor improvement effect and low utilization rate of improvement material in the traditional improvement scheme.

[0073] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for dynamically improving the adaptability of a full-stratum shield muck, characterized in that, The method comprises the following steps: obtaining stratum hydrological conditions of full-stratum shield muck, classifying strata based on the stratum hydrological conditions to obtain a plurality of stratum classification results; selecting different characteristic parameters as a plurality of improvement scheme indexes based on stratum characteristics corresponding to the plurality of stratum classification results, and setting a plurality of stratum improvement schemes based on the plurality of improvement scheme indexes; setting improvement scheme index thresholds corresponding to the stratum classification results; obtaining characteristic parameter values of the stratum classification results, judging the characteristic parameter values based on the improvement scheme index thresholds, and obtaining an optimal stratum improvement scheme based on a judgment result; the process of obtaining a plurality of stratum classification results comprises: obtaining geological survey data of a shield construction site, obtaining stratum hydrological conditions based on the geological survey data, and classifying strata into sandy strata, cohesive strata and highly eroded strata based on the stratum hydrological conditions; the process of selecting different characteristic parameters as a plurality of improvement scheme indexes comprises: selecting a stratum permeability coefficient as a first improvement scheme index based on stratum characteristics of the sandy strata; selecting a stratum consistency index as a second improvement scheme index based on stratum characteristics of the cohesive strata; selecting a rock abrasion index as a third improvement scheme index based on stratum characteristics of the highly eroded strata; the process of setting improvement scheme index thresholds corresponding to the stratum classification results comprises: setting a first fixed value of the stratum permeability coefficient as a first improvement scheme index threshold based on the sandy strata; setting a second fixed value of the stratum consistency index as a second improvement scheme index threshold based on the cohesive strata; setting a third fixed value of the rock abrasion index as a third improvement scheme index threshold based on the highly eroded strata; the process of obtaining an optimal stratum improvement scheme in the sandy strata comprises: judging the characteristic parameter values based on the first fixed value of the stratum permeability coefficient; if the characteristic parameter values are greater than or equal to the first fixed value, selecting an improvement scheme of mixing bentonite and gushing prevention agent; if the characteristic parameter values are less than the first fixed value, selecting an improvement scheme of mixing non-ionic foaming agent and gushing prevention agent; the process of obtaining an optimal stratum improvement scheme in the cohesive strata comprises: judging the characteristic parameter values based on the second fixed value of the stratum consistency index; if the characteristic parameter values are less than or equal to the second fixed value, selecting an improvement scheme of non-ionic foaming agent; if the characteristic parameter values are greater than the second fixed value, selecting an improvement scheme of mixing high-molecular anti-cohesion agent and non-ionic foaming agent; the process of obtaining an optimal stratum improvement scheme in the highly eroded strata comprises: judging the characteristic parameter values based on the third fixed value of the rock abrasion index; if the characteristic parameter values are less than or equal to the third fixed value, selecting an improvement scheme of mixing high-molecular wear-resistant agent and gushing prevention agent; if the characteristic parameter values are greater than the third fixed value, selecting an improvement scheme of jointly using high-molecular wear-resistant agent, bentonite and gushing prevention agent.

Images