Patent Application
20240102385
The invention relates to the technical field of tunnel construction blasting, and in particular to a blast hole arrangement structure used for blasting for a rheological soft-weak surrounding rock tunnel and a construction method for the rheological soft-weak surrounding rock tunnel.
Soft-weak surrounding rock generally refers to surrounding rock with soft-weak rock, low bearing capacity, developed joints and fissures, and broken structure, where rheological soft-weak surrounding rock refers to soft rock (similar to flowing mud) with media which are mainly rheological, and the rheological property is also known as viscosity. The rheological property of the soft rock includes elastic aftereffect, flowing, closure of structural surfaces, and slip deformation. The rheological property is mainly manifested in creep property and relaxation property of the soft rock, and attenuation property of flowing limit of the soft rock.
The surrounding rock tunnel can be excavated carefully only under the safety condition that curtain grouting reinforcement guarantees no collapse, no wall caving, no floor heave, no mud gushing, and no water permeation, and with an emergency plan at the same time. However, after grouting reinforcement, manual excavation and mechanical excavation can not be carried out in most cases, and a careful loose blasting method can only be adopted; however, vibration is difficultly controlled when the loose blasting method is adopted, potential safety hazards such as wall caving and collapse occur after blasting, and moreover, the blasting footage is small and the construction progress is slow.
The invention provides a blast hole arrangement structure used for blasting for a rheological soft-weak surrounding rock tunnel. A tunnel section subjected to grouting reinforcement is divided into two parts, that is, an upper half section and a lower half section, cutting vibration reduction holes used in coordination with cutting holes are formed in the upper half section, and the cutting vibration reduction holes are not charged and are filled with water bags only.
On the basis of the above solution, a plurality of first-layer vibration isolation holes are formed in a tunnel excavation contour line of the upper half section, and the first-layer vibration isolation holes are filled with soft mud.
On the basis of the above solution, a plurality of second-layer vibration isolation holes are formed in one side, close to the lower half section, of the first-layer vibration isolation holes, and the second-layer vibration isolation holes are filled with soft mud.
On the basis of the above solution, the upper half section is divided into a middle area, a left heading area and a right heading area which are used for separate divisional blasting; and the cutting holes and the cutting vibration reduction holes used in coordination with the cutting holes are respectively formed in the middle area, the left heading area and the right heading area.
On the basis of the above solution, a plurality of side vibration isolation holes are formed in the junction of the middle area and the left heading area and in the junction of the middle area and the right heading area, and the side vibration isolation holes are empty holes and are not filled inside.
On the basis of the above solution, the middle area is provided with a row of cutting holes vertically in both sides of the center line of the tunnel, and a row of cutting vibration reduction holes is formed vertically in the both sides of the center line of the tunnel and between the two rows of cutting holes.
On the basis of the above solution, a charging manner for the cutting holes in the middle area is that the adjacent cutting holes are charged at intervals in a manner of 3 rolls to 2 rolls to the bottoms of the holes, and the remainders of the blast holes are filled with stemming.
According to the blast hole arrangement structure used for blasting for the rheological soft-weak surrounding rock tunnel of the invention, a cutting vibration reduction hole filled with a water bag is provided at a place next to each cutting hole, so that a cutting blasting effect is improved, and moreover, excess energy is emptied and absorbed, propagation of shock waves and stress waves around is reduced, and vibration is reduced; and according to the invention, the plurality of first-layer vibration isolation holes are formed in a tunnel excavation contour line of the upper half section, second-layer vibration isolation holes are formed within the tunnel excavation contour line (referring to one side, close to the tunnel section, of an outer contour line of the tunnel); the vibration isolation holes are filled with soft mud; and the purpose is to prevent, absorb, reflect and refract the propagation of the blasting shock waves, stress waves and seismic waves. On the one hand, rock between every two holes is broken by tensile stress due to reflection and refraction of different interfaces and different media; on the other hand, part of excess parameters are emptied, the vibration is reduced, and stress is prevented from continuing to propagate outside the excavation contour line, so that a loose circle of blasting is controlled, a grouting effect outside an excavation boundary is protected from damage, and collapse after excavation is prevented. According to the invention, side vibration isolation holes are formed in the junction of the middle area and the left heading area and in the junction of the middle area and the right heading area of the upper half section, and the purpose is to effectively prevent, absorb, reflect and refract the propagation of the blasting shock waves, stress waves and seismic waves, prevent or reduce vibration and damage to a primary support, and prevent instability of the primary support. According to the blast hole arrangement structure and the blasting method of the invention, loose rock breaking is realized for whole section blasting, the throwing distance is very small, and the primary support is protected from collapse. The technical solution of the invention is applicable to construction for various tunnels and chambers in highways, railways, mines, subways and other similar stratum geologies (rheological soft-weak surrounding rocks).
The present invention will be further elaborated with reference to the following drawings and embodiments. It is to be pointed out that the following embodiments are intended to facilitate the understanding of the present invention, but have no limiting effect thereon.
A blast hole arrangement structure used for blasting for a rheological soft-weak surrounding rock tunnel, where a tunnel section subjected to grouting reinforcement is divided into two parts, that is, an upper half section 1 and a lower half section 2, cutting vibration reduction holes 1-2 used in coordination with cutting holes 1-1 are formed in the upper half section 1, and the cutting vibration reduction holes 1-2 are not charged and are filled with water bags only. During construction, the upper half section 1 is constructed at first, and then the lower half section 2 is constructed.
Since the charging quantity of simultaneous blasting of the cutting holes 1-1 is the largest, after detonating, a detonator drives explosive to complete blasting in a very short time, a large amount of gas is generated and a large amount of heat energy is released, the high-temperature and high-pressure gas breaks surrounding rocks and generates shock waves in media, part of the energy continues to break the rocks for work, and part of the energy is converted into stress waves and then converted into seismic waves. When each cutting hole is equipped with a cutting vibration reduction hole filled with a water bag, a free surface is added to help the cutting hole to break the rocks as much as possible, the excess energy may be emptied and absorbed, and the propagation of the shock waves and stress waves around is reduced.
On the basis of the above technical solution, as shown in
After the upper half section 1 is excavated in a blasting manner, a lot of machines pass through a slope of the lower half section 2 during muck removal, primary support and other steps, so that a rock mass of the lower half section 2 is disturbed for many times, and therefore, the lower half section 2 may generally be excavated by adopting manual pneumatic picks; if hardness of local parts of the lower half section 2 is large, hard blocks are chiseled away by using a breaking hammer, and then excavation is carried out by using an excavator; if the hardness of the lower half section 2 is too large, blasting may be carried out in a manner of conventional loose blasting, since the upper half section 1 is constructed, and the lower half section 2 is provided with vertical and horizontal free surfaces, the blasting effect is great; and therefore, the construction for the lower half section 2 will not be described too much in the patent.
As a specific solution for arrangement of the cutting holes 1-1 and the cutting vibration reduction holes 1-2 during blasting on the upper half section 1, as shown in
In order to reduce disturbance to the rock mass during separate blasting in the three areas, as shown in
Specifically, the hole depth of the first-layer vibration isolation holes 1-7 and the second-layer vibration isolation holes 1-8 is larger than that of all the blast holes. The specific quantity can be referred to in
In the above technical solution, an overall solution for the blast hole arrangement structure used for the blasting for the rheological soft-weak surrounding rock tunnel is already given, that is, the cutting holes are coordinated with the cutting vibration reduction holes and the vibration isolation holes, a good blasting effect is realized, and excessive interference to the rock mass is avoided. As a specific implementation solution, as shown in
In addition to the cutting holes 1-1 and the cutting vibration reduction holes 1-2, reaming holes 1-3, auxiliary holes 1-4, peripheral holes 1-5 and bottom holes 1-6 are further formed in the middle area 11. As a specific implementation solution, a plurality of reaming holes 1-3 are respectively formed vertically in one side, away from the center line of the tunnel, of the cutting holes 1-1; and preferably, three rows of the reaming holes 1-3 are respectively formed in one side of the center line of the tunnel. The reaming holes 1-3 are charged at intervals in a manner of 2 rolls to 1 roll. (Charging at intervals in a manner of 2 rolls to 1 roll means that the charging quantity of the reaming holes adjacent to the reaming holes charged with 2 rolls is 1 roll, or in other word, the charging quantity of the reaming holes adjacent to the reaming holes charged with 1 roll is 2 rolls, taking
A plurality of auxiliary holes 1-4 are formed between the cutting holes 1-1 and the tunnel excavation contour line of the upper half section. Specifically, three layers of the auxiliary holes 1-4 are formed, and respectively are first-layer auxiliary holes 1-41, second-layer auxiliary holes 1-42 and third-layer auxiliary holes 1-43, and on the tunnel section, connection lines among the center points of the auxiliary holes in each layer are arc-shaped, which is specifically shown in
A plurality of peripheral holes 1-5 are formed between the outermost-layer auxiliary holes 1-4 and the tunnel excavation contour line of the upper half section (or between the outermost-layer auxiliary holes 1-4 and the second layer of vibration isolation holes 1-8); the peripheral holes 1-5 are charged with 0.5 roll every other hole, and the openings of the charged peripheral holes are sealed with water stemming of 200 mm to 300 mm; and the uncharged peripheral holes 1-5 are fully filled with stemming.
A plurality of bottom holes 1-6 are formed in the junction of the middle area 11 and the lower half section 2, and the bottom holes 1-6 are charged at intervals in a manner of 2 rolls to 1 roll, (charging at intervals in a manner of 2 rolls to 1 roll means that the charging quantity of the bottom holes adjacent to the bottom holes charged with 2 rolls is 1 roll, or in other word, the charging quantity of the bottom holes adjacent to the bottom holes charged with 1 roll is 2 rolls, taking
Referring to Table 1 for the depths, inclination angles, detonating sequences and other blasting parameters of the cutting holes, the cutting vibration reduction holes, the reaming holes, the auxiliary holes, the peripheral holes, the bottom holes and the vibration isolation holes that are not described in detail in the embodiment, and the blasting parameters will not be described one by one here in detail.
On the basis of the blasting parameters in Table 1, the inclination angle between the first-layer vibration isolation holes 1-7 and a tunnel face, the inclination angle between the second-layer vibration isolation holes 1-8 and the tunnel face, and the inclination angle between the side vibration isolation holes 1-9 and the tunnel face are 90 degrees, the hole depth of the side vibration isolation holes 1-9 is 1.6 m, and the hole depth of the first-layer vibration isolation holes 1-7 and the hole depth of the second-layer vibration isolation holes 1-8 are 1.9 m.
The formation manners for the blast holes in the left heading area 12 and the right heading area 13 are illustrated by taking
In addition to the cutting holes 1-1 and the cutting vibration reduction holes 1-2, auxiliary holes 1-4, peripheral holes 1-5 and bottom holes 1-6 are further formed in the right heading area 13. Specifically,
The auxiliary holes 1-4 (as shown by F1 to F9 in
The peripheral holes 1-5 (as shown by Z1 to Z19 in
The bottom holes 1-6 (as shown by D1 to D11 in
The “explosive” in the patent refers to explosive, and in the patent, the explosive is emulsified explosive rolls with a specification of Phi 18 mm*300 mm*300 g.
The connection lines among the blast holes in
As shown in
S1: dividing a tunnel section subjected to grouting reinforcement into two parts, that is, an upper half section 1 and a lower half section 2, and carrying out blasting construction on the upper half section 1 at first; and
S2: dividing the upper half section 1 into a middle area 1, a left heading area 2 and a right heading area 3, blasting the left heading area 2 and completing primary support at first, then blasting the middle area 1 and completing primary support, and finally blasting the right heading area 3 and completing primary support. The primary support means supporting in the initial stage, for example, the primary support is carried out according to the following sequence: initial shotcreting, reinforcement mesh installation, steel arch frame erection, anchor rod installation, feet-lock anchor rod installation, and re-shotcreting. The excavation progress of the left heading area 2 is 5 m to 10 m in front of the middle area 1, and the excavation progress of the middle area 1 is 5 m to 10 m in front of the right heading area 3.
S3: After excavation and primary support for the upper half section 1 are completed, excavating the lower half section 2; and also carrying out reinforcement after the excavation is completed (the reinforcement manner is the same as that in step S2).
S4: after each cycle is completed, detaching a steel arch frame in the middle, and carrying out reinforcement construction for a secondary lining.
As a specific implementation solution, in step S1, a conventional grouting reinforcement manner may be adopted for the grouting reinforcement. In the invention, a multi-cycle full-section curtain grouting method adopting a large pipe shed with a diameter of Phi 108 is adopted, for example, an implementation length of first-circle grouting is 25 m, an implementation length of second-circle grouting is 30 m, an implementation length of third-circle grouting is 40 m, and so on; the grouting range is that reinforcement is carried out within 5.0 m to 6.0 m from top to bottom and left to right around the tunnel; the grouting manner is that backward segmented grouting is adopted, a segmenting length of grouting in the holes is determined according to the geological conditions of the drilled holes, and 3 m is preferred; and the grouting sequence is from outside to inside, and from top to bottom.
Referring to the example 1 and
Use Case
During construction for an undersea tunnel, the geologies of construction strata are completely weathered granodiorite (argillaceous medium-coarse sand), brown yellow in color, with gray white spots, and medium-coarse grain structures, most of the construction strata are plastic soil, and in a flowing plastic shape; and some of the construction strata are in a block structure, with hard rocks and well-developed fissure water, the hydrogeology is that a water inflow is 0.7 L/min·m to 2.0 L/min·m, and the construction strata are in a water-rich state and belong to rheological soft-weak surrounding rocks, as shown in
During construction, the construction method of the embodiments of the invention is adopted, and the arrangement structure of the embodiment 1 is adopted for blast hole formation in the upper half section 1, as shown in
The above descriptions are merely preferred embodiments of the present disclosure rather than limitations to the present disclosure in any form. Although the present disclosure has been disclosed in preferred embodiments, it is not intended to limit the invention. Anyone skilled in the art can make some changes or modifications to equivalent embodiments by using the above disclosed technical content without departing from the scope of the technical solution of the present disclosure. Any simple amendments, equivalent changes or modifications made to the above embodiments according to the technical essence of the present disclosure should fall in the scope of the technical solution of the present disclosure, without departing from the content of the technical solution of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202211159671.3 | Sep 2022 | CN | national |
