CN117781796A - Accurate blasting construction method for mud interlayer surrounding rock tunnel - Google Patents
Accurate blasting construction method for mud interlayer surrounding rock tunnel Download PDFInfo
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- 238000005422 blasting Methods 0.000 title claims abstract description 89
- 239000011435 rock Substances 0.000 title claims abstract description 74
- 239000011229 interlayer Substances 0.000 title claims abstract description 46
- 238000010276 construction Methods 0.000 title claims abstract description 38
- 238000009412 basement excavation Methods 0.000 claims abstract description 44
- 230000002093 peripheral effect Effects 0.000 claims abstract description 43
- 238000000034 method Methods 0.000 claims abstract description 32
- 238000005474 detonation Methods 0.000 claims abstract description 14
- 238000005553 drilling Methods 0.000 claims abstract description 11
- 239000002360 explosive Substances 0.000 claims description 40
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Abstract
The invention discloses a precise blasting construction method of a mud interlayer surrounding rock tunnel, which comprises the following steps: designing blasting blastholes according to tunnel excavation sections, wherein the blastholes comprise cut holes, auxiliary holes and peripheral holes which are sequentially arranged from the center of the excavation sections to excavation contour lines, the cut holes are provided with energy gathering hole structures, and the peripheral holes comprise charging holes and empty holes which are arranged at intervals; according to the designed blast hole, measuring and paying off the excavated section, laying hole sites and drilling construction; determining the charging parameters and charging structure of the blasthole; connecting a blasting hole charge line and a detonation network; and after detonation, checking and analyzing the blasting result, and adjusting blasting parameters according to the requirement. According to the method, the energy gathering hole structure is introduced through the slitting holes, the charging holes and the empty holes are arranged at intervals on the peripheral holes, and the blasting parameters of the peripheral holes are adjusted based on different positions of the mud interlayer relative to the tunnel excavation outline, so that the super-undermining rate and the safety risk caused by the mud interlayer can be reduced, the blasting construction efficiency is improved, and the method has wide popularization significance.
Description
Technical Field
The invention relates to the technical field of tunnel blasting construction, in particular to a precise blasting construction method for a mud interlayer surrounding rock tunnel.
Background
The rock blasting technology is an important rock breaking technology, is widely applied to various fields such as tunnel excavation, mineral exploitation, water conservancy construction, building demolition and the like, and creates huge economic and social benefits for social development and national construction. The technique sequentially arranges a cutting hole, an auxiliary hole and a peripheral hole from the proper position of the center of the excavation section to the excavation contour line, and sequentially detonates according to the sequence from inside to outside and a certain time interval. In the actual implementation of blasting, the effect is largely dependent on the blasting quality of the peripheral holes. Compared with the traditional uncontrolled blasting technology, the precise blasting technology can enable the blasting excavation surface to be smooth and flat, effectively control the phenomena of over-excavation and under-excavation of the tunnel, enhance the stability of surrounding rock and improve the efficiency and quality of tunnel construction.
The design of various parameters of blasting is also greatly different for different surrounding rock grades and rock stratum types. The blasting is carried out in surrounding rock with complete structure, joint and non-developing crack, and the blasting quality is easy to control. However, in practice, a large number of cracks, joints and interlayers exist in the tunnel surrounding rock, such as horizontal lamellar surrounding rock commonly exists in southwest areas of China, joints develop in the horizontal direction, and under the condition, the blasting is very difficult, and the overexplosion phenomenon occurs. The weak interlayer enables the propagation and attenuation rule of the stress wave after blasting to change, and simultaneously affects the rock breaking effect of the explosive gas. Therefore, the energy generated by blasting is not distributed to the expected organization and distribution and is consumed in a large amount around the eyes and in the interlayer, so that the arch profile required by the design is difficult to form after the blasting, the large block rate is high, and the phenomena of overexcavation and underexcavation are serious.
Disclosure of Invention
The invention aims at: aiming at the problem that the tunnel blasting excavation effect is difficult to control by adopting common blasting in the construction of the muded interlayer surrounding rock tunnel, the accurate blasting construction method of the muded interlayer surrounding rock tunnel is provided, the method can reduce the super-undermining rate and the safety risk caused by the muded interlayer, improves the blasting construction efficiency, and has wide popularization significance.
The invention is realized by the following technical scheme:
the invention provides a precise blasting construction method of a mud interlayer surrounding rock tunnel, which comprises the following steps:
designing blasting blastholes according to tunnel excavation sections, wherein the blastholes comprise cut holes, auxiliary holes and peripheral holes which are sequentially arranged from the center of the excavation sections to excavation contour lines, the cut holes are provided with energy gathering hole structures, and the peripheral holes comprise charging holes and empty holes which are arranged at intervals;
according to the designed blast hole, measuring and paying off the excavated section, laying hole sites and drilling construction;
determining the charging parameters and charging structure of the blasthole;
connecting a blasting hole charge line and a detonation network;
and after detonation, checking and analyzing the blasting result, and adjusting blasting parameters according to the requirement.
In some embodiments, the energy-gathering hole structure comprises two wedge bodies, a first telescopic rod, a second telescopic rod and an angle adjusting rod, wherein the two wedge body tips are oppositely arranged and extend along the axial direction of the slitting eye, the upper ends of the two wedge bodies are connected through the first telescopic rod, the second telescopic rod is axially arranged along the slitting eye, the lower ends of the second telescopic rod are connected with the first telescopic rod, and the upper ends of the second telescopic rod are connected with the angle adjusting rod.
In some embodiments, the method of cutting the hole is selected according to the geometric dimension of the tunnel excavation section, geological conditions, equipment conditions, drilling and blasting level and technical requirements of the excavation.
In some embodiments, the auxiliary eyes are interposed between the undercut eyes and the peripheral eyes, the auxiliary eyes being uniformly aligned according to tunnel surrounding rock and rock properties, the depth being the same as the blast cycle footage.
In some embodiments, the supplementary eyes are uniformly arranged at a distance of 80-90cm, and the distance between the outermost supplementary eye and the peripheral eye is determined by calculation.
In some embodiments, the charge holes and the void holes are spaced apart in parallel, and the hole spacing therebetween is determined by calculation.
In some embodiments, the void contains no explosive or a small amount of explosive at the bottom of the hole.
In some embodiments, the blasthole employs an air gap uncoupled charge structure.
In some embodiments, the borehole charge decoupling coefficient is 1.5-2.0.
In some embodiments, during blasting construction, peripheral eye blasting parameters in and near the sandwiches are adjusted according to the change in position of the sandwiches relative to the tunnel excavation contour.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. by introducing an energy gathering hole structure into the slitting hole, the energy distribution of the explosive is changed through the energy gathering hole effect, so that the explosive generates stress concentration effect along a preset direction to improve the local damage effect of the explosive, and the energy gathering direction can be adjusted according to the actual engineering requirement, thereby providing a more favorable temporary surface for subsequent blasting;
2. by arranging the empty holes among the charging holes of the peripheral holes, not only can effective guide holes be formed, the blasting forming is facilitated, but also consumable materials such as explosive, detonator, detonating cord and the like can be saved, and the purpose of reasonably excavating the agent is achieved;
3. based on different positions of the mud interlayer relative to the tunnel excavation outline, an influence area is determined, and peripheral eye blasting parameters in the influence area are changed, so that the aim of controlling the ultra-underexcavation is fulfilled.
Drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are needed in the examples will be briefly described below, it being understood that the following drawings only illustrate some examples of the present invention and therefore should not be considered as limiting the scope, and that other related drawings may be obtained from these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a flow chart of a precision blasting construction method of a mud interlayer surrounding rock tunnel in the invention;
FIG. 2 is a schematic diagram of the energy accumulating cavity structure in the present invention;
FIG. 3 is a schematic diagram of the void design principle in the present invention;
FIG. 4 is a schematic diagram of a charge structure of a blasthole in the present invention;
FIG. 5a is a schematic illustration of the present invention with the mud layer in a separated position from the tunnel excavation contour;
FIG. 5b is a schematic view of the present invention showing the sandwiches in a tangential position to the tunnel excavation contour;
FIG. 5c is a schematic view of the present invention where the argillization interlayer is at a shallow intersection with the tunnel excavation contour;
FIG. 5d is a schematic view of the present invention where the argillization interlayer is at a deep intersection with the tunnel excavation contour.
In the drawings, the reference numerals and corresponding part names:
1-wedge, 2-first telescopic link, 3-second telescopic link, 4-angle adjustment pole.
Detailed Description
For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions.
In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: there are three cases, a, B, a and B simultaneously. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
In the embodiments of the present application, the same reference numerals denote the same components, and in the interest of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, etc. dimensions of the various components in the embodiments of the present application, as well as the overall thickness, length, width, etc. dimensions of the integrated device, are illustrative only and should not be construed as limiting the present application in any way.
In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural sheets" refers to two or more (including two), unless specifically defined otherwise.
In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of describing the embodiments of the present application and for simplifying the description, rather than indicating or implying that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.
In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances.
Examples
Referring to fig. 1, the precise blasting construction method for the surrounding rock tunnel with the mud interlayer provided in the embodiment of the application includes:
designing blasting blastholes according to tunnel excavation sections, wherein the blastholes comprise cut holes, auxiliary holes and peripheral holes which are sequentially arranged from the center of the excavation sections to excavation contour lines, the cut holes are provided with energy gathering hole structures, and the peripheral holes comprise charging holes and empty holes which are arranged at intervals;
according to the designed blast hole, measuring and paying off the excavated section, laying hole sites and drilling construction;
determining the charging parameters and charging structure of the blasthole;
connecting a blasting hole charge line and a detonation network;
and after detonation, checking and analyzing the blasting result, and adjusting blasting parameters according to the requirement.
Referring to fig. 2, according to some embodiments of the present application, the energy-gathering hole structure includes two wedge bodies 1, a first telescopic rod 2, a second telescopic rod 3 and an angle adjusting rod 4, wherein the two wedge bodies 1 are oppositely arranged at the tip and extend along the axial direction of the slitting eye, the two wedge bodies 1 are connected at the upper ends thereof by the first telescopic rod 2, the second telescopic rod 3 is axially arranged along the slitting eye, the lower ends thereof are connected with the first telescopic rod 2, and the upper ends thereof are connected with the angle adjusting rod 4.
Because of the existence of the two wedges in the cut hole during charging, the medicine bag is formed with symmetrical energy gathering holes after the cut hole is charged, and the energy of the medicine bag can be released to the greatest extent. When the medicine bag has energy gathering holes, the medicine bag can locally gather in the direction of the energy gathering holes to generate ultra-normal blasting energy, effectively control the breaking direction, prevent other cracks from forming and extending, reduce the unevenness, improve the yield and provide a better blank face for auxiliary eyes. Simultaneously can drive the wedge through the angle adjustment pole and rotate, and then drive below cartridge bag rotation control angle, the size can adjust different length through first telescopic link to adapt to towards different cartridge bags, adjusts different length through the second telescopic link to adapt to towards different medicine hole depths.
When the mud interlayer is positioned at the slitting position, if the blasting direction is controlled inaccurately, the blasting energy is controlled unevenly, so that the mud layer part is damaged greatly, a good and even empty face cannot be formed, and balance is achieved by controlling the inclined direction of the explosive bag energy. The cutting hole is introduced into the energy gathering hole structure, and the energy distribution of the explosive is changed through the energy gathering hole effect, so that the explosive generates stress concentration effect along a preset direction to improve the local damage effect of the explosive. After the explosion of the common explosive package, detonation products fly around along the direction approximately perpendicular to the surface of the explosive package, and under the condition of the same spherical radius, the energy acted on the medium is approximately the same in all directions, but when the energy gathering explosive package structure is adopted, the detonation products gather towards the energy gathering hole direction to form a detonation product with high temperature, high pressure, high speed and high energy density, the acting capacity of the energy gathering hole direction is far greater than that of the common explosive package structure, and the energy gathering direction can be adjusted according to the actual engineering requirement, so that a more favorable free surface is provided for the subsequent explosion.
According to some embodiments of the application, tunnel excavation is constructed according to the new Otto principle, and different excavation methods are selected according to different surrounding rock grades, such as a full-section method, a step method, an arc pilot pit reserved core soil, a CD method, a CRD method and the like. The excavation method generally adopted by each level of surrounding rock is as follows: excavating the I and II-level surrounding rocks by adopting a full-section method and a step method; excavating III-level surrounding rock by adopting a step method; excavating IV-level surrounding rock by adopting a step method or a three-step method; and excavating the V-class surrounding rock by adopting a pilot pit reserved core soil, a double-side-wall pilot pit method, a CRD method and the like.
According to some embodiments of the present application, the undercut eye pattern is generally classified into three types of straight undercut, oblique undercut, and hybrid undercut. The selection of the cutting hole mode needs to be considered according to the geometric dimension of the tunnel excavation section, geological conditions, equipment conditions, drilling hole blasting level and the technical requirement of excavation. The straight-hole cutting is suitable for operation of a rock drilling trolley, has a small excavation section and is used for excavating a hard integral rock stratum; the drilling depth is not limited by the section. The inclined hole cutting is suitable for artificial air drills to cut holes and larger tunnels; the drilling depth is limited by the section width or height; when the cyclic footage is changed, the change of the angle of the blast hole is complex. At present, the tunnel construction basically adopts a hand-held rock drill to punch inclined holes for slitting. The mixed cutting means the mixed use of more than two cutting modes, and is generally used when the rock is particularly hard or the tunnel excavation section is large.
According to some embodiments of the present application, the auxiliary eyes are interposed between the undercut eyes and the peripheral eyes, and the auxiliary eyes are uniformly arranged according to the properties of surrounding rock and rock of the tunnel, and the depth is the same as the blasting circulation footage. Blasting cyclic footage control: generally, the circulating footage of the V-class surrounding rock is controlled to be 0.8-1.0 m; IV-level surrounding rock circulating footage is controlled to be 1.5-2.0 m; the depth of the class II and class III surrounding rock blastholes is preferably not more than 4.0m, and the handheld air drill is not more than 3.5m.
According to some embodiments of the present application, the supplementary eyes are uniformly arranged with a distance of 80-90cm, and the distance between the outermost supplementary eye and the peripheral eye is calculated as follows: d=e/M, where E is the peripheral eye spacing determined on a blast demand; m is the blast hole density coefficient, and m=0.8 is selected.
According to some embodiments of the present application, the peripheral eye parameter design is typically such that the peripheral eye spacing e=30 to 60cm, typically medium hard rock and above is 45 to 60cm and soft rock is 35 to 45cm. The relative distance m=E/V=0.5-1.0, wherein V is the minimum resisting line of the peripheral eyes. The thickness of the photoblast layer is typically determined at a value of m=0.8. The peripheral eye has an outer slope angle of not more than 3 DEG and an outer slope value of not more than 20cm, and the minimum resistance line is calculated to account for the influence value.
According to some embodiments of the present application, the charge holes and the empty holes are arranged in parallel and spaced apart, and the hole spacing therebetween is determined by calculation. The peripheral holes for realizing blasting are divided into two types, namely a charging hole and a hollow hole. The explosive charging hole is used for breaking the rock through the explosive loaded in the hole, so that the impact and explosion heat performance of the explosive is fully exerted, and the rock is broken and the rock slag is thrown under the combined action of the impact wave, the heat and the explosion gas. The explosive charging holes and the empty holes are arranged at intervals, so that the explosive performance can be fully exerted, the empty hole effect can be generated, a good blasting effect is achieved, and the consumption of a fire worker is saved.
According to some embodiments of the present application, no explosive is contained in the hollow hole or a small amount of explosive is contained at the bottom of the hole, mainly to provide a free surface for the charging hole, and the implementation of blasting adjacent to the charging hole is facilitated. And moreover, the hollow holes provide a compensation space for the breaking of the rock, and the rock generated by blasting can be extruded in the hollow holes, so that the blasting form of the peripheral outline of the tunnel is facilitated, and the better half porosity is formed.
The arrangement principle of the empty holes is shown in fig. 3, wherein A is a charging hole, B is an empty hole, point P is located at a position of a connecting line between the charging hole and the empty hole, the distance from the charging hole A is R, and the distance from the charging hole B is R. rB is the radius of the hole, θ is the included angle between any direction and the connecting line direction between the blast holes, the distance between the charging hole and the hole is E, and the specific calculation is as follows:
according to the blasting principle, at the position r away from the center of the blasthole, radial stress and tangential stress suffered by the rock mass are respectively as follows:
σ θ ＝bσ r
wherein: sigma (sigma) r Is radial stress; sigma (sigma) θ Is tangential stress; b is the ratio of tangential stress to radial stress,
v is poisson's ratio, a is stress wave attenuation index, a=2-b; t (T) b Is the radius of the blasthole; p (P) 2 Is the impact stress on the borehole wall.
The impact pressure on the wall of the blast hole is as follows:
wherein: ρ 0 Is the density of the explosive; d is the explosive explosion velocity; d, d c 、d b The diameter of the explosive roll and the diameter of the blasthole are respectively; n is the pressure increase coefficient of detonation product striking the borehole wall.
The air interval uncoupled charge is adopted, and the impact pressure on the wall of the blast hole is as follows:
wherein: l (L) a Is the air column spacing length; l (L) c For the charge length of the blasthole.
Rock tensile stress sigma in tangential direction θ Under the action, the conditions for generating the stretch-break cracks are as follows:
σ θ ≥S td
wherein: s is S td Is the dynamic tensile strength of the rock.
The rock particle damage in the area between the charge blast hole and the space hole adopts the minimum tensile stress damage criterion, and the criterion adopts the dynamic tensile strength value of the rock.
Wherein the radius T of the fracture zone K The calculation formula of the distance E between the charging hole and the empty hole is as follows:
2T b P b ＝(E-2T k )S td
wherein: p (P) a Is the detonation pressure of the gas in the gas cylinder,D i is the ideal detonation velocity of the explosive; v (V) c Is the charge volume; v (V) b Is the borehole volume; k is the adiabatic index of the agglomerated explosive and is taken as 1.4; h is the isentropic index of the condensed explosive and is taken as 3; p (P) k The critical pressure of the explosion gas expansion process is approximately 100Mpa.
When the dynamic tensile strength of the rock is consistent with the tensile strength near the empty hole, the area of the crushing area is maximum, the crack on the hole wall is fully initiated and expanded, the cracks between the empty hole and the charging hole are mutually communicated, and the explosive is most efficiently utilized. And calculating according to the formula to obtain the distance between the empty hole and the charging hole.
According to some embodiments of the present application, the blasthole employs an air gap uncoupled charge configuration, as shown in fig. 4. In order to reduce the earthquake effect generated by tunneling blasting and weaken the damage of blasting to surrounding rocks of a tunnel, each blast hole adopts uncoupled charging. If the condition of using the detonating cord exists, the peripheral holes are preferably detonated by the detonating cord, so that all the peripheral holes can be detonated simultaneously, and a better blasting effect is obtained.
According to some embodiments of the present application, the borehole charge decoupling coefficient is 1.5-2.0. The geometric diameter of the medicated roll is always selected from four specifications of phi 25, phi 32, phi 35 and phi 40. The main materials are non-electric detonating cord, no. 2 rock ammonium nitrate explosive and No. 2 rock emulsion explosive, and the explosive adopts coiled explosive with phi 25mm and phi 32 mm.
Calculating the explosive loading quantity of a blasting single hole: q=n×l×r, where Q is the single hole charge of the blasthole; n is the packing factor of the blast hole; l is the hole depth of the blast hole; r is the mass of each meter of explosive.
According to some embodiments of the application, during blasting construction, peripheral eye blasting parameters in and near the sandwiches are adjusted according to the position change of the sandwiches relative to the tunnel excavation contour line. Aiming at peripheral holes in the mud interlayer, blasting parameters different from those of the peripheral holes of the sandstone layer are taken, and the overbreak amount of the mudstone part can be effectively controlled. Based on different positions of the mud interlayer relative to the tunnel excavation outline, an influence area is determined, and peripheral eye blasting parameters in the influence area are changed, so that the aim of controlling the ultra-underexcavation is fulfilled.
The common mud interlayer penetrates through the tunnel, part of the inside of the tunnel excavation contour line can be observed through the face condition, and the area outside the tunnel contour line can be detected according to the following steps: (1) presume subsidence, convergence inhomogeneous isoptic abnormal region on the basis of monitoring the measurement data; (2) the tunnel construction environment data is effectively analyzed, and the geological structure and rock layer characteristics are basically known; (3) carrying out geophysical prospecting technology according to the actual condition of the tunnel, and interpreting the geological structure and rock layer characteristics of the tunnel environment in a layered and classified manner; (4) drilling based on the above work, focusing on exploration of geophysical prospecting abnormal zone, large water content rock zone, important paragraph and problematic surface layer structure zone; (5) sampling in situ, taking various tests around the drill hole, testing basic mechanical parameters of the rock sample, and determining the type and range of the rock stratum.
In general, the relative positions of the mud interlayer and the tunnel excavation contour line, which can be encountered in engineering, mainly have several forms of separation, tangency, shallow intersection and deep intersection, as shown in fig. 5 a-5 d. According to the relative position of the mud interlayer and the tunnel excavation contour line, the mud interlayer is divided into an influence area A, an influence area B and an influence area C, wherein the influence area A and the influence area B easily form overexcavation, and the influence area C easily forms underexcavation. The peripheral eye blasting parameter adjustment measure is based on the following reasons:
(1) Due to the low-strength characteristic of the mud interlayer, the damage degree of blast hole explosion in the interlayer to the interlayer rock mass is obviously larger than that of adjacent rock mass, and the damage range exceeds the tunnel excavation contour line so as to form overexcavation in the influence area A. Meanwhile, due to the reflection and stretching effects of the explosion stress wave on the lower layer surface of the interlayer, the explosion cracks of the influence area B extend and develop to the interlayer, so that the overexcavation of the influence area B is caused. Furthermore, the interlayer cuts off the penetration of the explosion cracks among the blast holes, and the propagation of explosion stress waves leads the rock mass influence area C on the upper side of the interlayer to have partial underexcavation.
(2) Because of the 'gas wedge' effect of the explosive gas in the interlayer, expansion cracking occurs on the lower layer surface of the interlayer, in the process, on one hand, the phenomenon of ultra-digging in the affected area A and the affected area B is aggravated, and on the other hand, the explosive gas pressure is rapidly reduced and flows to the deep of the interlayer along the open cracks to cause a great deal of energy loss, so that the surrounding rock outside the explosive layer cannot be damaged to cause undermining.
Aiming at the reason of the super-underexcavation of the mud interlayer and the different positions of the super-underexcavation relative to the tunnel photo-explosion layer, the method provides peripheral eye explosion parameter adjustment measures which are specifically as follows:
(1) Impact area a: the distance between the peripheral eyes is reduced by 10% on the basis of the original distance; the drug loading quantity of the single hole of the peripheral eye is reduced by 25% on the original basis; the peripheral eyes adopt a spaced charge structure, so that the charge quantity of the middle space is reduced to 50% of the original charge quantity, and the spacing distance is reduced accordingly.
(2) Impact zone B: the drug loading quantity of the single hole of the peripheral eye is reduced by 15% on the original basis; the peripheral eyes adopt a spaced charge structure, so that the charge quantity of the middle space is reduced to 50% of the original charge quantity, and the spacing distance is reduced accordingly.
(3) Impact zone C: the distance between the peripheral eyes is increased by 10% on the basis of the original distance; the single hole drug loading of the peripheral eye is increased by 20% on the original basis.
Through the improvement of the blasting construction method, the accurate blasting construction method suitable for the mud interlayer surrounding rock tunnel is formed, the super-underexcavation quantity is reduced, the blasting efficiency is improved, the domestic gap of blasting construction of the weak interlayer tunnel is further filled, references are provided for blasting construction of the follow-up mud interlayer surrounding rock tunnel, and the method has wide popularization significance.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. The accurate blasting construction method of the mud interlayer surrounding rock tunnel is characterized by comprising the following steps of:
designing blasting blastholes according to tunnel excavation sections, wherein the blastholes comprise cut holes, auxiliary holes and peripheral holes which are sequentially arranged from the center of the excavation sections to excavation contour lines, the cut holes are provided with energy gathering hole structures, and the peripheral holes comprise charging holes and empty holes which are arranged at intervals;
according to the designed blast hole, measuring and paying off the excavated section, laying hole sites and drilling construction;
determining the charging parameters and charging structure of the blasthole;
connecting a blasting hole charge line and a detonation network;
and after detonation, checking and analyzing the blasting result, and adjusting blasting parameters according to the requirement.
2. The method for precisely blasting construction of the mudsandwich surrounding rock tunnel according to claim 1, wherein the energy gathering hole structure comprises two wedge bodies, a first telescopic rod, a second telescopic rod and an angle adjusting rod, the tips of the two wedge bodies are oppositely arranged and extend along the axial direction of the slitting hole, the upper ends of the two wedge bodies are connected through the first telescopic rod, the second telescopic rod is axially arranged along the slitting hole, the lower end of the second telescopic rod is connected with the first telescopic rod, and the upper end of the second telescopic rod is connected with the angle adjusting rod.
3. The method for precisely blasting construction of the muded interlayer surrounding rock tunnel according to claim 1, wherein the cutting hole mode is selected according to the geometric dimension of the tunnel excavation section, geological conditions, equipment conditions, drilling hole blasting level and technical requirements of excavation.
4. The method for precisely blasting construction of a argillaceous interlayer surrounding rock tunnel according to claim 1, wherein the auxiliary eyes are arranged between the slitting eyes and the peripheral eyes, are uniformly arranged according to the properties of surrounding rock and rock of the tunnel, and have the same depth as a blasting circulation footage.
5. The method for precisely blasting construction of the mudsandwich surrounding rock tunnel according to claim 4, wherein the ring distances of the auxiliary eyes are uniformly arranged according to 80-90cm, and the ring distance between the outermost auxiliary eye and the surrounding eye is determined through calculation.
6. The method for precisely blasting construction of a muded interlayer surrounding rock tunnel according to claim 1, wherein the charging holes and the empty holes are arranged in parallel at intervals, and the hole spacing between the charging holes and the empty holes is determined through calculation.
7. The method for precisely blasting construction of the muded interlayer surrounding rock tunnel according to claim 6, wherein no explosive is filled in the hollow hole or a small amount of explosive is filled in the bottom of the hole.
8. The method for precisely blasting construction of the argillaceous interlayer surrounding rock tunnel according to claim 1, wherein the blasthole adopts an air interval uncoupled charging structure.
9. The method for precisely blasting construction of the argillized interlayer surrounding rock tunnel according to claim 8, wherein the shot hole charge uncoupling coefficient is 1.5-2.0.
10. The method for precisely blasting construction of the mudsandwich surrounding rock tunnel according to claim 1, wherein in the blasting construction process, peripheral hole blasting parameters in and near the mudsandwich are adjusted according to the position change of the mudsandwich relative to the tunnel excavation contour line.
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