CN114737973B - Construction method for vertical shaft construction to penetrate through hectometer-level structural fracture zone stratum - Google Patents

Construction method for vertical shaft construction to penetrate through hectometer-level structural fracture zone stratum Download PDF

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CN114737973B
CN114737973B CN202210417823.9A CN202210417823A CN114737973B CN 114737973 B CN114737973 B CN 114737973B CN 202210417823 A CN202210417823 A CN 202210417823A CN 114737973 B CN114737973 B CN 114737973B
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vertical shaft
construction
displacement
concrete
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CN114737973A (en
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胡彦博
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Nanjing Tech University
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Nanjing Tech University
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D1/00—Sinking shafts
    • E21D1/08—Sinking shafts while moving the lining downwards
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D20/00—Setting anchoring-bolts
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/0006—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by the bolt material
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D5/00—Lining shafts; Linings therefor
    • E21D5/11—Lining shafts; Linings therefor with combinations of different materials, e.g. wood, metal, concrete
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D5/00—Lining shafts; Linings therefor
    • E21D5/12—Accessories for making shaft linings, e.g. suspended cradles, shutterings
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D7/00—Shaft equipment, e.g. timbering within the shaft
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/20—Hydro energy

Abstract

The invention provides a construction method for penetrating through hectometer-level structural fractured zone strata in vertical shaft construction, which is a mechanism based on mutual coordination of three factors, namely surrounding rock displacement control, support parameter adjustment and process time control, and firstly, the displacement rate of the surrounding rock of an excavated fractured zone is obtained based on methods such as analog analysis, preset excavation section height, in-situ test and the like; secondly, theoretical analysis and support parameter adjustment are utilized to establish a mathematical model of a tunneling system when the vertical shaft passes through a deep ultra-thick structural broken zone; and finally, decomposing the construction data fusion relation by combining procedures under special conditions, and constructing the construction method of the vertical shaft when the construction of the bedrock section passes through the stratum of the huge thick structure crushed zone. The invention can effectively solve the problem of safe tunneling when a broken zone is constructed in a long distance in the coal mine vertical shaft construction.

Description

Construction method for vertical shaft construction to penetrate through hectometer-level structural fracture zone stratum
Technical Field
The invention belongs to the field of mineral engineering, and particularly relates to a construction method for penetrating through a hundred-meter-level structural broken zone stratum in vertical shaft construction.
Background
Coal will be in leading position in the energy structure of China for a long time in the present stage and 50 years from now on. The invention mainly relates to the technical field of coal mine vertical shaft construction, in particular to a method for preventing the horizontal displacement of a tunneling section from appearing after excavation due to the coupling effect of surrounding rock crushing and deep crustal stress when a huge thick fault crushing zone is encountered below 400 m (a bedrock section) in the vertical depth in the coal mine vertical shaft construction process, so that the phenomenon of uncontrollable phenomenon can be caused, normal supporting cannot be realized, and the integral falling of the upper well wall can be caused if forced tunneling, so that catastrophic major accidents can be caused. Therefore, the construction method for penetrating through the hectometer-level structural fractured zone stratum in the vertical shaft construction is summarized and invented based on the actual engineering case, and has an important guiding function on the mining construction engineering in China.
In the prior art, the construction equipment and the construction process of a vertical shaft are mainly researched and modified, and no relevant report is provided for a treatment method under the condition of special tectonic geology (deep hundred-meter-level fault fracture zone).
Disclosure of Invention
The invention aims to provide a construction method for vertical shaft construction to penetrate through a hundred-meter-level structural broken zone stratum, which can ensure high-quality safe vertical shaft construction under the condition that the horizontal displacement rate is overlarge when the vertical shaft construction encounters a huge thick structural broken zone, and provide scientific guarantee for safe tunneling under the condition that a coal mine vertical shaft is developed to penetrate through a special geological background. In order to realize the purpose, the invention adopts the following technical scheme:
a construction method for penetrating through a hundred-meter-level structural fracture zone stratum in vertical shaft construction comprises the following steps:
step (1), controlling displacement of broken surrounding rocks of a well wall during vertical shaft excavation, and providing a physical environment for measuring the maximum displacement speed of the surrounding rocks of the well wall, so that the maximum displacement speed of the surrounding rocks in four directions of the well wall is finally obtainedvThe method specifically comprises the following steps:
(11) Setting a displacement control factor, comprising: the height of an excavation supporting cycle section is reduced, and effective temporary supporting is realized;
(12) According to the displacement control factor, monitoring the displacement of the wall surrounding rock after excavation, the concrete steps include:
(121) Reducing the height of a circulating tunneling section, and setting the height of the circulating tunneling section to be half of the height of a normal excavation section in a displacement monitoring stage;
(122) After temporary support, displacement sensors are arranged at four directions of the well wall, and a full-automatic total station is arranged at the center of the well wall for testing to obtain the maximum displacement speed of the surrounding rock in four directions of the well wallv；
Step (2), establishing a tunneling system mathematical model:
establishing a mathematical model of a tunneling system:
Figure DEST_PATH_IMAGE001
wherein:
xthe radius increment of the vertical shaft excavation is mm, and the value range is 0-800 mm;
y-circularly advancing in the vertical shaft by mm;
v-maximum displacement speed of the surrounding rock in four directions of the well wall, mm/h;
h 1 -thickness of polyethylene cushion, mm; the range of the initial preset value is 50-120 mm;
T 1 -an incremental excavation radius ofxThe circulating footage for vertical shaft tunneling isyThe output value of the time function required by the vertical well section is an empirical value,h；
T 2 increment of radius ofxThe circulating footage for vertical shaft tunneling isyThe output value of the time function of the temporary support of the vertical shaft section is an experimental value,h；
T 3 -the vertical shaft driving cycle footage isyThe output value of the vertical shaft tunneling section template positioning time function is an experimental value,h；
T 4 -a concrete placement time function, the output value of which is an empirical value,h；
f T -a process engineering time fusion function expression, the output value of which is a verified value;
step (3) based on the tunneling system mathematical model, variable y and variableh 1 Solving design factors of the vertical shaft supporting material; the adjustable design factors of the vertical shaft supporting material comprise: temporary support design parameters, concrete initial setting control time and polyethylene cushion pad size;
wherein the temporary support design parameters are solved as
Figure 100002_DEST_PATH_IMAGE002
In, removex、Other influencing factors than y; wherein the content of the first and second substances,xfor is to
Figure 751034DEST_PATH_IMAGE002
、
Figure DEST_PATH_IMAGE003
Has negligible influenceSlightly disregarding;
solving the initial setting control time of the concrete as
Figure 100002_DEST_PATH_IMAGE004
In, removex、Other influencing factors than y; in (1),xto pair
Figure 714180DEST_PATH_IMAGE004
Have a negligible effect;
the thickness of the polyethylene cushion pad is determined ash 1 The empirical value of (a) of (b),h 1 experienced value of- v= buffer compression timet 2 ；
The method comprises the following specific steps:
(31) Solving the design parameters of temporary support: according to the mathematical model of the tunneling system, obtaining the optimal solution of temporary support time to control the construction time of the temporary support; the temporary supporting time is the sum of anchor rod construction time and metal mesh supporting construction time;
(32) Solving the initial setting control time of the concrete: the concrete strength grade of the vertical shaft construction is C50, the C50 concrete is upgraded in proportion, the accelerator is added, and the initial setting strength is adjusted to reach 2.00 MPa within two hours;
(33) Solving for polyethylene cushion size: adding a polyethylene buffer cushion on the huge thick structure crushing belt;
the polyethylene cushion is designed into a rectangular plate, the long edge is the high length of the tunneling circulation section, and the width is properly adjusted according to the excavation radius of a shaft and is less than 1.00 m;
the thickness of the polyethylene cushion is solved according to the mathematical model of the tunneling system and the variable y to ensure the allowable displacement time (t) In the method, the concrete well wall is poured to reach the requirement of initial setting of 2.00 MPa;
and (4) acquiring an empirical value of each process time function based on different values of the step (3), the step (2) and the vertical shaft tunneling circulating footage y, and acquiring buffering compression resisting time based on the step (3)t 2 And each stepEmpirical value of time function, buffer compression timet 2 According to the followingf T Carrying out fusion and connection:
the time experience value of the tunneling construction process of the vertical shaft passing through the hectometer-level structural broken zone comprises the following steps: the method comprises the following steps of (1) obtaining a shaft excavation tunneling time empirical value, a temporary support and permanent support time empirical value, a template positioning time empirical value, a concrete pouring time empirical value and a concrete initial setting time empirical value;
(41) Shaft excavation and tunneling time: the time from the beginning of excavating the next section of height after the last section of height is formed by pouring concrete to the time from the time of excavating to the time of designing the adjusted size (the adjusted height of the circulating section and the size of the excavating radius);
(42) Temporary support and permanent support time: after the vertical shaft is excavated to the design size, temporary support can be constructed, and the temporary support comprises a resin anchor rod, a metal net and a polyethylene cushion; the permanent support at the present stage is a double-layer steel bar binding fixed support;
combining actual production industrial and mining and personnel organization conditions, and obtaining the length of time used for supporting in a shaft stage according to a class comparison method;
(43) Template positioning time: after the binding and fixing of the reinforcing steel bars are finished, the bottom cleaning and leveling of the edge angles of the template are needed, the cylindrical steel template is poured into the concrete below, the size of the center line is positioned, the template is fixed, and the pouring of the concrete is waited; the process can be estimated by a similarity method;
(44) Concrete pouring time: calculating according to the amount of concrete used for pouring;
(45) Initial setting time of concrete: obtained by step (32);
(46) The process is fused and linked: according to the followingf T Adjusting the cross-over time of the process to obtain the necessary timet x ；
Step (5) according to the maximum allowable displacement timet max And necessary timet x Iterating to solve for the optimal allowed displacement timet o ：
According to the mathematical model of the tunneling system, the method can be transformed into the following steps:
Figure DEST_PATH_IMAGE005
；
wherein, the allowable displacement time t includes: maximum allowable displacement time t max And an optimum allowable displacement time t o (ii) a Optimal allowable displacement timet o =x/v(ii) a Maximum allowable displacement timet max =
Figure 100002_DEST_PATH_IMAGE006
/
Figure DEST_PATH_IMAGE007
(ii) a Necessary time of dayt x =
Figure 100002_DEST_PATH_IMAGE008
；
When the necessary time is neededt x = maximum allowed displacement timet max At the time of needt x Taking the maximum value, and obtaining the maximum value of the vertical shaft excavation radius increment x;
when the necessary time is neededt x = optimal allowable displacement timet o ≦ maximum allowed displacement timet max Then, allowing the displacement time t to obtain an optimal solution, and obtaining the minimum value of the vertical shaft excavation radius increment x;
Figure DEST_PATH_IMAGE009
；
wherein, the first and the second end of the pipe are connected with each other,xthe optimal solution = the product of the actual excavation time and the displacement speed of the broken surrounding rock = the optimal allowable displacement timet o The product of the displacement speed of the broken surrounding rock;
when allowing the displacement timet< time necessaryt x And (2) readjusting the maximum displacement speed of the surrounding rock in the vertical shaft tunneling circulating footage y and the shaft wall in the step (1) in four directionsvAnd (4) designing factors of the well support material in the step (3), and then performing the steps (4) - (5) until necessary timet x = optimum allowable displacementBetweent o 。
Preferably, in step (11), the effective temporary support specifically includes: according to the height of the construction circulation section, the length of the resin anchor rod and the size of the metal mesh can be correspondingly adjusted.
Preferably, step (11) further comprises: grouting transformation and surrounding rock disturbance reduction;
wherein, slip casting transformation specifically includes: carrying out concrete bottom sealing on the construction working face of the vertical shaft, and carrying out grouting transformation on the surrounding rock at the bottom of the vertical shaft which is not constructed by utilizing cement grout or chemical grout in a segmented manner;
reducing the disturbance of the surrounding rock specifically comprises: when the temporary anchor rod is used for supporting, a hole needs to be drilled, and the direction of hole forming and blanking is changed to a pneumatic coal drill or an electric coal drill to do spiral tangent movement along the well wall.
Preferably, in step (122), the four orientations of the borehole wall include N0 ° W, N90 ° E, S0 ° W, N90 ° W.
Preferably, in the step (2),h 1 is 70mm.
Preferably, in step (33), the concrete step of solving the thickness of the polyethylene cushion according to the tunneling system mathematical model and the variable y comprises the following steps:
the polyethylene cushion pad may be sized to satisfy the following conditions:
the thickness Z of the polyethylene cushion is less than or equal to the optimal solution X of the vertical shaft excavation radius increment;
and (3) the height L of the polyethylene cushion = the adjusted vertical shaft tunneling circulation footage y.
Preferably, in step (31), the specific step of obtaining the optimal solution of the temporary support time according to the mathematical model of the tunneling system comprises the following steps:
and comprehensively determining the length of the anchor rod and the size of the metal mesh according to the adjusted vertical shaft tunneling circulation footage y and the optimal solution X of the vertical shaft excavation radius increment so as to reduce the construction time of temporary support.
Compared with the prior art, the invention has the advantages that:
(1) And reversely setting the mutual coordination time among the material adjusting process and the time control process and inside according to the displacement rate after the surrounding rock is excavated.
(2) The time necessary for the vertical shaft construction process is prolonged by adding a polyethylene buffer zone.
Therefore, when the deep construction of the vertical shaft meets the stratum of the broken zone with a huge thick structure, the tunneling can be rapidly and safely carried out, the cost control is relatively low, and the construction quality can be effectively guaranteed.
Drawings
FIG. 1 is a flow chart of a method embodying the present invention;
FIG. 2 is a diagram of a process decomposition construction data fusion relation case;
fig. 3 is a case diagram of a well wall supporting system for a vertical shaft construction penetrating through a stratum with a huge thick crushing zone.
Detailed Description
The present invention will now be described in more detail with reference to the accompanying schematic drawings, in which preferred embodiments of the invention are shown, it being understood that one skilled in the art may modify the invention herein described while still achieving the advantageous effects of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.
As shown in figure 1, the construction method for penetrating through a hectometer-level structural broken zone stratum in vertical shaft construction is a system method for vertical shaft tunneling formed on the basis of three aspects of excavation surrounding rock displacement control, support material size adjustment, process time fusion control and the like, and can effectively solve the problem of safe tunneling when a broken zone is constructed in a long distance in coal mine vertical shaft construction in the global range. The specific embodiment is as follows:
(1) The displacement control of the broken surrounding rock of the shaft wall of the vertical shaft excavation provides a physical environment for measuring the maximum displacement speed of the surrounding rock of the shaft wall, thereby finally obtaining the maximum displacement speed of the surrounding rock in four directions of the shaft wallv. Specifically, the method comprises the steps (11) to (12).
(11) Setting displacement control factors, wherein the displacement control factors comprise: grouting transformation, reduction of the height of a free surface, effective temporary support and reduction of surrounding rock disturbance.
The method comprises the following specific steps:
Figure 100002_DEST_PATH_IMAGE010
grouting reconstruction: when the vertical shaft is in the condition of being incapable of effectively tunneling a huge thick structure crushing zone, concrete bottom sealing can be carried out on the vertical shaft construction working face; and (3) performing grouting transformation on the surrounding rock at the bottom of the vertical shaft which is not constructed by utilizing cement grout or chemical grout in a segmented manner (the concrete grouting length and grouting control parameters are determined according to the preference of site construction conditions).
Figure DEST_PATH_IMAGE011
Reducing the height of the free surface: the construction process is changed, the height of the excavation supporting and supporting circulating tunneling section is reduced (the height of the common vertical shaft construction circulating section is 4 m), and the monitoring data collection in the early stage is generally carried out according to half of the height of the normal section tunneling section.
Figure 100002_DEST_PATH_IMAGE012
Effective temporary support: according to the construction cycle section height, the size of the resin anchor rod and the metal mesh can be adjusted correspondingly to form a rapid supporting process, so that the purpose of rapid temporary supporting is achieved (for example, the length of the anchor rod is changed from 2.00 m to 1.50 m, and the length of the metal mesh is changed from 1.00 m to 1.00 m).
Figure DEST_PATH_IMAGE013
Reducing the disturbance of surrounding rocks: after excavation, secondary disturbance of broken wall surrounding rocks of a well wall manually is reduced as much as possible, and the method is mainly divided into two aspects, namely firstly, drilling is required to be constructed during temporary anchor rod supporting, generally, a pneumatic tool for mining is used for hole forming, and the air coal drill or the electric coal drill is used for hole forming instead, so that the disturbance of the broken surrounding rocks is reduced; on the other hand, the improvement of the blanking system is that a common blanking opening forms an included angle of 45 degrees with the well wall when concrete is poured, and certain impact acting force can be applied to the well wall when the concrete is put down, so that disturbance is caused to the broken well wall and the temporary support, and the proposal is made for the blanking systemTransformation is carried out, the direction of blanking is spiral tangential motion along the well wall as far as possible, and then the impact disturbance caused to broken surrounding rocks and temporary support is reduced.
(12) And monitoring the displacement of the wall surrounding rock after excavation according to the displacement control factor.
The method comprises the following specific steps:
(121) The height of the free surface is reduced, the height of a circulating tunneling section (a circulating footage y for vertical shaft tunneling) is reduced, and half of the height of a normal excavating section (the height of the normal excavating section is 4.00 m) is generally set in a monitoring displacement stage.
(122) After temporary support, displacement sensors are arranged on four directions of a well wall N0-degree W, N90-degree E, S0-degree W, N90-degree W and the like, and a full-automatic total station is arranged in the center of the well wall for testing. The testing aim is to obtain the maximum displacement speed of the surrounding rock in four directions of the well wallv。
(2) And (5) establishing a mathematical model of the tunneling system.
According to a construction method flow chart (figure 1) of vertical shaft construction for crossing a hundred-meter-level structure fracture zone stratum, a tunneling system mathematical model is established as shown in the following formula (1).
Figure 714757DEST_PATH_IMAGE001
（ 1 ）；
In the formula:
xthe radius increment of the vertical shaft excavation is mm, and the value range is 0-800 mm;
y-circularly advancing the vertical shaft, namely circularly advancing the section height by mm;
v-maximum displacement speed of the surrounding rock in four directions of the well wall, mm/h;
h 1 -thickness of polyethylene cushion, mm; the value range of the initial preset value is 50-120 mm;
T 1 -an excavation radius increment ofxThe circulating footage for vertical shaft tunneling isyThe output value of the time function required by the vertical well section is an experimental value,h；
T 2 -halfThe diameter increment isxThe circulating footage for vertical shaft tunneling isyThe output value of the time function of the temporary support of the vertical shaft section is an experimental value,h；
T 3 -the circulation footage of the vertical shaft driving isyThe output value of the vertical shaft tunneling section template positioning time function is an experimental value,h；
T 4 -a concrete placement time function, the output value of which is an empirical value,h；
f T -a procedure construction time fusion function expression, the output value of which is a verified value.
According to the mathematical model formula (1) of the tunneling system, the tunneling circulation footage variable (can be) of the vertical shafty) The time of each process is calculated by different values of (2) to satisfy the establishment of a mathematical model, and the time can be obtained in the subsequent step (5)xIs calculated, as shown in equation (2).
Figure 100002_DEST_PATH_IMAGE014
（ 2 ）；
(3) And (5) adjusting the design of the vertical shaft supporting material. I.e. based on the mathematical model of the tunnelling system, the variable y and the variableh 1 And solving the design factor of the vertical shaft supporting material.
The adjustable factors of the vertical shaft supporting material comprise: temporary support design parameters, concrete initial setting control time and polyethylene cushion pad size.
Wherein, the temporary support design parameters are solved as
Figure 231671DEST_PATH_IMAGE002
In, removex、Other influencing factors than y; wherein, the variable of the factor x is limited to be less than or equal to 800 mm, so that the method is carried out at the momentxTo pair
Figure 842781DEST_PATH_IMAGE002
、
Figure 524298DEST_PATH_IMAGE003
The effect of (c) is negligible.
Solving the initial setting control time of the concrete as
Figure 588069DEST_PATH_IMAGE004
In and removex、Other influencing factors than y; wherein the variable limit of the factor x is less than or equal to 800 mm,xto pair
Figure 318127DEST_PATH_IMAGE004
The effect of (c) is negligible.
The thickness of the polyethylene cushion pad is determined ash 1 Is determined based on the empirical value of (a),h 1 experienced value of- v= buffer compression timet 2 。
The method comprises the following specific steps:
(31) Solving temporary support design parameters: and (3) solving an optimal solution (anchor rod and metal mesh support construction time) of temporary support time according to the mathematical model of the tunneling system, wherein the temporary support time is the sum of the anchor rod construction time and the metal mesh support construction time, and then comprehensively determining the length of the anchor rod and the size of the metal mesh according to the optimal solution of the temporary support time so as to control the temporary support construction time. For example: the length of the anchor rod can be 1.50-1.80 m, and the length of the metal mesh can be 1.00 x 1.00 m, so that the construction time of temporary support is controlled.
The concrete steps of solving the optimal solution of the temporary support time comprise:
and comprehensively determining the length of the anchor rod (properly reducing the length of the anchor rod) and the size of the metal net according to the adjusted vertical shaft tunneling circulation footage y and the adjusted vertical shaft excavation radius increment optimal solution (X) so as to reduce the construction time of temporary support. The method can be determined according to experience values of a vertical shaft construction site. Known to mining technicians.
(32) Solving the initial setting control time of the concrete: the concrete strength grade of the vertical shaft construction is generally C50, the C50 concrete needs to be proportioned and upgraded, the accelerator is added, and the initial setting strength is adjusted to reach 2.00 MPa within two hours; the method aims to prevent the displacement of the broken belt by the initial setting of the concrete well wall in the allowable displacement time of the broken belt well wall surrounding rock without deformation and damage.
(33) Solving for polyethylene cushion size: the addition of the polyethylene buffer cushion is a core element for solving the problem of safe construction method of the vertical shaft passing through the huge-thickness structural broken belt.
The polyethylene cushion is preferably a rectangular plate in design size, the long edge is preferably the height and the length of a tunneling circulation section, the width can be properly adjusted according to the shaft excavation radius, and the design size is not more than 1.00 m (the transportation and the field laying are convenient). And the shaft excavation radius = the actual excavation radius after the designed excavation radius is increased by X.
The thickness of the polyethylene cushion is solved according to the mathematical model of the tunneling system and the variable y to ensure the allowable displacement time (t) And the concrete well wall is poured to reach the initial setting requirement of 2.00 MPa.
Polyethylene cushions have a major role:
Figure 580481DEST_PATH_IMAGE010
buffering the extrusion stress: the polyethylene cushion pad has high compressibility, plays a role in buffering broken surrounding rocks of a well wall, avoids the increase of horizontal stress, avoids the displacement of the broken surrounding rocks from exceeding the limit, and generates extrusion stress on an unformed concrete well wall, so that the concrete well wall deforms, and the thickness of the concrete well wall cannot reach the standard.
Figure 370583DEST_PATH_IMAGE011
Buffering impact power: the polyethylene cushion pads are laid on the temporary supports, the broken belt well wall surrounding rocks after the temporary supports are physically separated from the concrete well wall, and after the templates are positioned, when the concrete well wall is poured, impact disturbance of concrete on the broken belt surrounding rocks during blanking can be reduced.
The thickness solving method of the polyethylene cushion pad comprises the following specific steps of:
the polyethylene cushion pad may be sized to satisfy the following condition:
the thickness (Z) of the polyethylene cushion is less than or equal to the optimal solution (X) of the radius increment of the vertical shaft excavation;
polyethylene cushion height (L) = adjusted vertical shaft driving circulation footage y.
(4) And (5) controlling the process time. Namely acquiring empirical values of time functions of all working procedures based on different values of the step (3), the step (2) and the vertical shaft tunneling circulation footage y, and acquiring buffering pressure-resistant time based on the step (3)t 2 And the empirical value of each procedure time function and the buffering compression-resistant time are usedt 2 According tof T And performing fusion splicing.
The time experience value of the tunneling construction process of the vertical shaft passing through the hundred-meter-level structural crushing zone comprises the following steps: the method comprises the following steps of obtaining a shaft excavation tunneling time empirical value, a temporary support and permanent support time empirical value, a template positioning time empirical value, a concrete pouring time empirical value and a concrete initial setting time empirical value. The analysis was specific according to case (A).
(41) Shaft excavation and tunneling time: and (3) the time from the beginning of excavating the next section of height after the last section of height cast concrete is formed to the time from the beginning of excavating to the time from the design of the adjusted size (the adjusted height of the circulating section and the size of the excavating radius).
Case (a):
the Liuzhuang air shaft of the three river sharp coal mine is located in Peipin county in Xuzhou city of Jiangsu province, 90km away from Xuzhou city area in south China, the transportation is convenient, and the coordinate of the Liuzhuang air shaft is X =3861458.000, Y =39479645.000; the diameter of the shaft of the air shaft is 6.00 m, the elevation of the shaft mouth is plus 37.50 m, and the elevation of the shaft bottom is minus 792.50 m. The Liuzhu air shaft coordinate is near the abundant fracture structure zone and is influenced by the large fracture structure of the area, and a huge fault fracture zone of a shaft appears in a chalk system stratum and a Jurassic system stratum, so that great difficulty appears in the vertical shaft construction process.
Case (A) is adjusted according to a mathematical model of the tunneling system:
the height of the circular excavation section is 2.20m; the shaft excavation and tunneling time is 2.50 h. Namely, the height of the circular excavation section is 2.20m, and the excavation can be finished after 2.50 h is measured by analogy analysis according to actual construction condition scenes.
(42) Temporary support and permanent support time: after the vertical shaft is excavated to the design size, a temporary support can be constructed, and the temporary support comprises a resin anchor rod, a metal mesh and a polyethylene cushion pad; the permanent support at the present stage is a double-layer steel bar binding fixed support (figure 3).
Case (a): the length of the anchor rod in the temporary support is adjusted to 1.50 m, the length of the metal net is 1.00 x 1.00 m, and the size of the polyethylene cushion pad is 70mm. The permanent supporting double-layer steel bars are unchanged according to the original design, namely the vertical bars have the diameter of 16 mm and the distance of 300 mm; the diameter of the horizontal rib is 18 mm, and the distance between the horizontal ribs is 300 mm; the connecting ribs are 8mm in diameter and 600 mm in spacing, as shown in figure 3.
And combining actual production industrial and mining and personnel organization conditions, and obtaining the length of time for supporting in the shaft stage with the required completion section height of 2.20m by a class-comparison method, wherein the length of time is 2.00 h.
(43) Template positioning time: and after the reinforcement is fixed, the edge of the template is leveled by cleaning the bottom of the vertical shaft, the cylindrical steel template is poured by the concrete below, the central line is positioned and sized, and the template is fixed to wait for pouring the concrete. The process can be estimated by using a similarity method.
In case (A), the time for positioning the template was 0.30 hours.
(44) And (3) concrete pouring time: before the previous process is completed by binding and fixing the reinforcing steel bar support under the well, the concrete pump truck is required to be completely standby at the well mouth in the ground dispatching. And a blanking system is formed immediately after the double-layer steel bar support is finished, and the blanking system is not interrupted in the concrete conveying process. The time required for this process can be estimated based on the amount of concrete used in the placement.
Case (a): the concrete pouring time is 2.00 h.
(45) Initial setting time of concrete: obtained by step (32); the initial setting time needs to be increased by adding an accelerating agent for proportioning again, and the initial setting time reaches 2.00 h and 2.00 MPa while the strength reaches the design requirement.
(46) The process is fused and linked: according to the followingf T Adjusting the cross-over time of the process to obtain the necessary timet x 。
In actual construction, cross synchronous construction is not generally carried out under normal conditions, but in order to safely and quickly pass through extreme stratum conditions under the condition of encountering special geological background, the cross time of the working procedures is properly adjusted under the condition of application and filing examination and approval, so that safe tunneling is realized.
Case (a): the process fusion splice is shown in FIG. 2.
(5) According to maximum allowable displacement time: (t max ) And necessary time (t x ) Iterate to solve for the optimal allowed displacement time (t o ）。
According to the mathematical model of the tunneling system, the deformation can be as follows:
Figure 921650DEST_PATH_IMAGE005
；
wherein, the allowable displacement time t comprises: maximum allowable displacement time t max And an optimal allowable displacement time t o (ii) a Optimal allowable displacement timet o =x/v(ii) a Maximum allowable displacement timet max =
Figure 455399DEST_PATH_IMAGE006
/
Figure 778452DEST_PATH_IMAGE007
(ii) a Necessary time of dayt x =
Figure 739455DEST_PATH_IMAGE008
；
When the necessary time is neededt x = maximum allowed displacement timet max Time, necessary time (a)t x ) Taking the maximum value, and obtaining the maximum value of the vertical shaft excavation radius increment (x);
when the necessary time is neededt x = optimal allowable displacement timet o ≦ maximum allowed displacement timet max And then, allowing the displacement time (t) to obtain an optimal solution, and obtaining the minimum value (optimal solution) of the vertical shaft excavation radius increment x:
Figure 100002_DEST_PATH_IMAGE016
wherein the content of the first and second substances,xthe optimal solution = the product of the actual excavation time and the displacement speed of the broken surrounding rock = the optimal allowable displacement timet o And the product of the displacement velocity of the broken surrounding rock.
When allowing the displacement timet< time necessaryt x And (2) readjusting the maximum displacement speed of the surrounding rock in the circulating tunneling section in the step (1) in the height y direction and the wall of the well in four directionsvAnd (4) designing factors of the well support material in the step (3), and then performing the steps (4) - (5) until necessary timet x = optimal allowable displacement timet o 。
In conclusion, based on the steps (1) to (5) and in combination with the case (a), as shown in fig. 2 to 3, the solving process of the excavation radius 3678mm is as follows:
presetting the height of a circulation section: assuming a reduction in segment height to the normal segment height, typically 2.00 m.
The known data are as follows: when the height of the excavation section is 2.00 m, the maximum displacement speed of the well wall (in-situ test); the normal commercial polyethylene cushion is typically 70mm (other thicknesses may be customized), with a pre-selected thickness of 70 mm; the method comprises the following steps that 1.50 m of anchor rods are preset in temporary support, the spacing between rows is 700 x 700 mm, and 1.00 x 1.00 m of metal nets are preset; the original design of the double-layer reinforcing steel bar is unchanged;
data can be obtained (field techniques should know the item): minimum excavation radius (original design excavation radius size) and buffering compression-resisting timet 2 The method comprises the following steps of excavating a circulation section, supporting time, template positioning time, concrete pouring and initial setting time.
Figure 308976DEST_PATH_IMAGE010
Monitoring that the displacement rate in the N90-degree W direction is the maximum, wherein the maximum displacement speed is 12mm/h;
Figure 380837DEST_PATH_IMAGE011
optimal allowable displacement timet o Calculating the displacement of the inner broken surrounding rock:
Figure 100002_DEST_PATH_IMAGE018
wherein: 6.50 Is a necessary time (process matching time: (t 1 ) + buffer compression resistance time (a)t 2 ) I.e. fusion time), i.e.: allowable displacement time (t）。
Figure 352205DEST_PATH_IMAGE012
The wall is excavated to the radius size as shown in figure 3.
Excavation radius = original design excavation radius size + optimal allowable displacement timet o The displacement of the inner broken surrounding rock =3600 + 78 = 3678 (mm).
Wherein: the original design excavation radius size is 3600 mm.
The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. A construction method for penetrating through a hundred-meter-level structural fractured zone stratum in vertical shaft construction is characterized by comprising the following steps of:
step (1), controlling displacement of broken surrounding rocks of a well wall during vertical shaft excavation, and providing a physical environment for measuring the maximum displacement speed of the surrounding rocks of the well wall, so that the maximum displacement speed of the surrounding rocks in four directions of the well wall is finally obtainedvThe method specifically comprises the following steps:
(11) Setting a displacement control factor, comprising: the height of an excavation supporting circulation section is reduced, and temporary supporting is effectively realized;
(12) According to the displacement control factor, monitoring the displacement of the wall surrounding rock after excavation, the concrete steps include:
(121) The height of a circulating tunneling section is reduced, and half of the height of a normal excavation section of the circulating tunneling section is set in a monitoring displacement stage;
(122) After temporary support, displacement sensors are arranged at four directions of the well wall, and a full-automatic total station is arranged at the center of the well wall for testing to obtain the maximum displacement speed of the surrounding rock in four directions of the well wallv；
Step (2), establishing a mathematical model of the tunneling system:
establishing a mathematical model of a tunneling system:
Figure DEST_PATH_IMAGE002
wherein:
xthe excavation radius increment of the vertical shaft is mm, and the value range is 0-800 mm;
y-circularly advancing in the vertical shaft by mm;
v-maximum displacement speed of the surrounding rock in four directions of the well wall, mm/h;
h 1 -thickness of polyethylene cushion, mm; the range of the initial preset value is 50-120 mm;
T 1 -an excavation radius increment ofxThe circulating footage for vertical shaft tunneling isyThe output value of the time function required by the vertical well section is an experimental value,h；
T 2 increment of radius ofxThe circulating footage for vertical shaft tunneling isyThe output value of the time function of the temporary support of the vertical shaft section is an experience value,h；
T 3 -the circulation footage of the vertical shaft driving isyThe output value of the vertical shaft tunneling section template positioning time function is an experimental value,h；
T 4 concrete placement time function, the output value of which is a testValue of a step of,h；
f T -a process engineering time fusion function expression, the output value of which is an empirical value;
step (3) based on a tunneling system mathematical model, variable y and variableh 1 Solving a design factor of a vertical shaft supporting material; the adjustable design factors of the vertical shaft supporting material comprise: temporary support design parameters, concrete initial setting control time and polyethylene cushion pad size;
wherein, the temporary support design parameters are solved as
Figure DEST_PATH_IMAGE004
In and removex、Other influencing factors than y;xto pair
Figure 445797DEST_PATH_IMAGE004
、
Figure DEST_PATH_IMAGE006
Neglecting the influence of (2);
solving the initial setting control time of the concrete as
Figure DEST_PATH_IMAGE008
In and removex、Other influencing factors than y;xto pair
Figure 441566DEST_PATH_IMAGE008
The influence of (2) is ignored;
the thickness of the polyethylene cushion pad is determined ash 1 The empirical value of (a) of (b),h 1 is greater than or equal to v= buffer compression timet 2 ；
The method comprises the following specific steps:
(31) Solving temporary support design parameters: according to a mathematical model of a tunneling system, solving an optimal solution of temporary support time to control the construction time of temporary support; wherein the temporary supporting time is the sum of the construction time of the anchor rod and the construction time of the metal mesh support,
(32) Solving the initial setting control time of the concrete: the concrete strength grade selected for the vertical shaft construction is C50, the proportion of the C50 concrete is upgraded, the accelerator is added, and the initial setting strength is adjusted to reach 2.00 MPa within two hours;
(33) Solving for polyethylene cushion size: adding a polyethylene buffer cushion on the huge thick structure crushing belt;
the polyethylene cushion is designed into a rectangular plate, the long edge is the height of a tunneling circulation section, and the width is adjusted according to the excavation radius of a shaft and is less than 1.00 m;
the thickness of the polyethylene cushion is solved according to the mathematical model of the tunneling system and the variable y to ensure the allowable displacement time (t) In the method, the concrete well wall is poured to reach the requirement of initial setting of 2.00 MPa;
and (4) acquiring an empirical value of each process time function based on different values of the step (3), the step (2) and the vertical shaft tunneling circulating footage y, and acquiring buffering compression resisting time based on the step (3)t 2 And the empirical value and the buffering compression time of each procedure time function are usedt 2 According to the followingf T Carrying out fusion and connection:
the time experience value of the tunneling construction process of the vertical shaft passing through the hectometer-level structural crushing zone comprises the following steps: the method comprises the following steps of (1) excavating and tunneling time empirical value of a shaft, temporary support and permanent support time empirical value, template positioning time empirical value, concrete pouring time empirical value and concrete initial setting time empirical value;
(41) Shaft excavation and tunneling time: the time from the beginning of excavating the next section of height after the last section of height is formed by pouring concrete to the time for adjusting the height and the excavating radius of the circulation section after the excavation is finished;
(42) Temporary support and permanent support time: after the vertical shaft is excavated to the design size, a temporary support can be constructed, and the temporary support comprises a resin anchor rod, a metal mesh and a polyethylene cushion pad; the permanent support at the present stage is a double-layer steel bar binding fixed support;
obtaining the length of time used for supporting in a shaft stage according to a class comparison method by combining actual production industrial and mining and personnel organization conditions;
(43) Template positioning time: after the binding and fixing of the steel bars are finished, the bottom cleaning of the vertical shaft is needed to level the edge angles of the template, the cylindrical steel template is poured with concrete below, the size of the center line is located, the template is fixed, and the concrete is waited to be poured; the process can be estimated by a similarity method;
(44) Concrete pouring time: calculating according to the amount of concrete used for pouring;
(45) Initial setting time of concrete: obtained by step (32);
(46) The process is fused and linked: according tof T Adjusting the cross-over time of the process to obtain the necessary timet x ；
Step (5) according to the maximum allowable displacement timet max And necessary timet x Iterate to solve for the optimal allowed displacement timet o ：
According to the mathematical model of the tunneling system, the deformation can be as follows:
Figure DEST_PATH_IMAGE010
；
wherein the allowable displacement time t includes: maximum allowable displacement time t max And an optimum allowable displacement time t o (ii) a Optimal allowable displacement timet o = x/v(ii) a Maximum allowable displacement timet max =
Figure DEST_PATH_IMAGE012
/
Figure DEST_PATH_IMAGE014
(ii) a Necessary time of dayt x =
Figure DEST_PATH_IMAGE016
；
When the necessary time is neededt x = maximum allowed displacement timet max When it is necessary tot x Taking the maximum value, and obtaining the maximum value of x;
when the necessary time is neededt x = optimal allowable displacement timet o ≦ maximum allowed displacement timet max Allowing the displacement time t to obtain an optimal solution, and obtaining the minimum value of x;
Figure DEST_PATH_IMAGE018
；
wherein the content of the first and second substances,xthe optimal solution = the product of the actual excavation time and the displacement speed of the broken surrounding rock = the optimal allowable displacement timet o The product of the displacement velocity of the broken surrounding rock;
when allowing the displacement timet< time necessaryt x In the process, the maximum displacement speed of the surrounding rock in the four directions of the vertical shaft circular driving footage y and the well wall in the step (1) is readjustedvAnd (4) designing factors of the well support material in the step (3), and then performing the steps (4) - (5) until necessary timet x = optimal allowable displacement timet o 。
2. The construction method for penetrating through hundred-meter-level structural fractured zone stratum in vertical shaft construction according to claim 1, wherein in the step (11), the effective temporary support specifically comprises the following steps: according to the height of the construction circulation section, the length of the resin anchor rod and the size of the metal mesh can be correspondingly adjusted.
3. A construction method for traversing hectometer-level fractured zone ground layer in vertical shaft construction according to claim 1, wherein the step (11) further comprises: grouting transformation and surrounding rock disturbance reduction;
wherein, slip casting transformation specifically includes: carrying out concrete bottom sealing on the construction working face of the vertical shaft, and carrying out grouting transformation on the surrounding rock at the bottom of the vertical shaft which is not constructed by utilizing cement grout or chemical grout in a segmented manner;
the method for reducing the surrounding rock disturbance specifically comprises the following steps: during temporary anchor rod support, drilling is required to be constructed, and the direction of hole forming and discharging is changed to be spiral tangential motion along the well wall by using a pneumatic coal drill or an electric coal drill.
4. A method as claimed in claim 1, wherein the four orientations of the borehole wall in step (122) comprise N0 ° W, N90 ° E, S0 ° W, N90 ° W.
5. The construction method for penetrating through a hundred-meter-scale structure fractured zone stratum in vertical shaft construction according to claim 1, wherein in the step (2),h 1 is 70mm.
6. The construction method for traversing hundred-meter-scale formation of fractured zone formation in vertical shaft construction according to claim 1, wherein the concrete step of solving the thickness of the polyethylene cushion according to the mathematical model of the tunneling system and the variable y in the step (33) comprises the following steps:
the polyethylene cushion pad may be sized to satisfy the following conditions:
the thickness Z of the polyethylene cushion is less than or equal to the optimal solution X of the vertical shaft excavation radius increment;
and (3) the height L of the polyethylene cushion = the adjusted vertical shaft tunneling circulation footage y.
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