阅读说明：本技术 一种复杂环境下露天深孔台阶预裂孔逐孔起爆预裂***成缝的方法 (Hole-by-hole initiation presplitting blasting crack forming method for open-air deep hole step presplitting hole under complex environment ) 是由 李祥龙 张其虎 袁芝斌 侯猛 王子琛 母永烨 吴霄 张希 段应明 于 2019-09-25 设计创作，主要内容包括：本发明涉及一种复杂环境下露天深孔台阶预裂孔逐孔起爆预裂爆破成缝的方法,属于爆破技术领域。本发明沿台阶爆破的最终境界线即设计轮廓线先进行预裂爆破,预裂孔应领先于主爆孔100ms以上起爆,在主爆孔与被保护岩体之间预先炸出一条裂缝,形成预裂缝后,再起爆缓冲爆孔组和主爆孔组,预裂缝能减小主爆孔组的爆破地震效应,对周围岩体的破坏比较轻微,保护岩体的完整性,降低工作量；对周围民房、文物以及其它周围建构筑物振动小、预留岩体扰动小、稳定性好、成缝效果好等；可以获得平整光滑的岩石壁面,大大减少超挖,保持围岩的稳定性。(The invention relates to a method for initiating and presplitting blasting crack by hole for an open deep hole step presplitting hole under a complex environment, belonging to the technical field of blasting. The method carries out presplitting blasting along the final boundary line of step blasting, namely the design contour line, the presplitting hole is initiated more than 100ms before the main blasting hole, a crack is pre-blasted between the main blasting hole and the protected rock mass, after the presplitting is formed, the blasting buffer blasting hole group and the main blasting hole group are initiated, the presplitting can reduce the blasting earthquake effect of the main blasting hole group, the damage to the surrounding rock mass is slight, the integrity of the rock mass is protected, and the workload is reduced; the vibration to the surrounding civil houses, cultural relics and other surrounding building structures is small, the disturbance of the reserved rock mass is small, the stability is good, the seam forming effect is good, and the like; the smooth rock wall surface can be obtained, the overbreak is greatly reduced, and the stability of surrounding rocks is kept.)

1. A method for initiating and presplitting blasting crack formation of an open-air deep hole step presplitting hole one by one under a complex environment is characterized by comprising the following specific steps:

(1) uniformly arranging inclined pre-splitting holes on the outline of the foundation pit excavated by the open-air deep hole step in a complex design environment, and arranging axial uncoupled air spaced charging devices in the pre-splitting holes;

(2) arranging a plurality of rows of main blasting holes in a main blasting area of a foundation pit excavation surface, wherein the row spacing of the main blasting holes is equal, the hole spacing of the main blasting holes is equal, a row of buffer holes are formed between the main blasting holes and the pre-cracking holes, the direction angles of the buffer holes and the pre-cracking holes are the same, and axial uncoupled air spaced explosive devices are arranged in the buffer holes and the main blasting holes;

(3) the axial uncoupled air spaced explosive charging device in the pre-splitting hole controls accurate delay hole-by-hole detonation through a digital electronic detonator;

(4) the axial uncoupled air spaced charging device of the buffer hole controls accurate delay hole-by-hole detonation through a digital electronic detonator;

(5) the axial uncoupled air spaced explosive charging device in the main explosion hole controls accurate delay to detonate row by row and hole by hole through a digital electronic detonator; and the pre-crack hole, the buffer hole and the main explosion hole are sequentially detonated to form the pre-crack.

2. The method for hole-by-hole initiation and presplitting blasting of the open-air deep-hole step presplitting hole to form the crack under the complex environment according to claim 1, which is characterized in that: the aperture of the pre-split hole is 50-200 mm, the hole pitch of the pre-split hole is 8-12 times of the diameter of the pre-split hole, and the delay time of the digital electronic detonator of the pre-split hole is 8-12 ms; the horizontal distance between the pre-cracked holes and the orifices of the adjacent rows of main blasting holes is 3-3.5 m, and the horizontal distance between the pre-cracked holes and the bottoms of the adjacent rows of main blasting holes is 2.5-3 m.

3. The method for hole-by-hole initiation and presplitting blasting of the open-air deep-hole step presplitting hole to form the crack under the complex environment according to claim 1, which is characterized in that: the aperture of the buffer hole is 50-200 mm, the distance between the buffer hole and the pre-splitting hole is 2-4 m, and the hole pitch of the buffer hole is 4-5 m; loose slag with the height of 1-1.5 m is filled at the bottom of the buffer hole, the delay time of the pre-splitting hole and the buffer hole is 100-200 ms, and the delay time of the buffer hole and the adjacent row of main blast holes is 12-25 ms.

4. The method for hole-by-hole initiation and presplitting blasting of the open-air deep-hole step presplitting hole to form the crack under the complex environment according to claim 1, which is characterized in that: the hole spacing of each row of main blast holes is 8-12 times of the aperture of the main blast holes, the row spacing of the adjacent rows of main blast holes is 1-1.2 times of the hole spacing of the main blast holes, the inter-hole delay time of the digital electronic detonators of the main blast holes is 25-75 ms, the inter-row delay time of the digital electronic detonators of the main blast holes is 50-400 ms, the drilling inclination angle of the main blast hole row and the row is 0-30 degrees, and the drilling inclination angle of the main blast hole row and the row is the same or different.

5. The method for hole-by-hole initiation and presplitting blasting of the open-air deep-hole step presplitting hole to form the crack under the complex environment according to claim 4, which is characterized in that: the main blasting hole is a vertical deep hole.

6. The method for hole-by-hole initiation and presplitting blasting of the open-air deep-hole step presplitting hole to form the crack under the complex environment according to claim 1, which is characterized in that: the complex environment is that civil houses, cultural relics or other building structures exist within 100m around the explosion area.

Technical Field

The invention relates to a method for initiating and presplitting blasting crack by hole for an open deep hole step presplitting hole under a complex environment, belonging to the technical field of engineering blasting.

Background

During blasting operation, because the explosive can generate strong shock waves and high-pressure gas when exploding in the blast hole, the surrounding rock mass is broken and cracked. In many projects in China, such as strip mine slopes, hydraulic buildings, traffic cutting, building foundation pits, tunnels and the excavation of underground buildings, blasting boundaries need to be controlled, over excavation and under excavation do not occur, and rock mass on the excavation boundaries also need to be kept complete and stable as much as possible.

The boundary control blasting includes presplitting blasting and smooth blasting. The method comprises the steps of drilling a row of pre-splitting holes with proper hole spacing along the design contour line of an excavation boundary in advance, detonating the powder charge in the pre-splitting ore before excavating a main rock body by adopting a non-coupling powder charge structure or other special powder charge structures, and forming a pre-crack penetrating through a blast hole between an explosion area and a reserved area so as to reduce the damage to the reserved rock body and form a smoother contour surface when the main rock body is exploded, wherein the explosion technology is called pre-splitting explosion. The latter is that the smooth blasting hole is blasted after the main rock body in the designed section is blasted and collapsed, so as to form a smooth and flat excavation surface which penetrates through the smooth blasting hole, and the blasting is called smooth blasting.

The smooth blasting refers to a controlled blasting technology which meets the design requirements of a contour line after blasting and is a leveling rule of a blank surface by correctly selecting blasting parameters and a reasonable construction method and carrying out sectional differential blasting, and is also one of important technologies for supporting the principle of a new Olympic method. Compared with the traditional method, the method for excavating the tunnel by applying the smooth blasting technology has the advantages that the blasting effect of the explosives of the peripheral holes can be effectively controlled, so that the disturbance to the surrounding rock is reduced, the stability of the surrounding rock is kept, the self-supporting effect of the surrounding rock is fully exerted, the construction safety is ensured, the overbreak and the underexcavation can be reduced, the engineering quality and the efficiency are improved, and the cost is saved.

The presplitting blasting is that when the stone excavation is carried out, a through crack with a certain width is blasted along a design contour line before the blasting of a main blasting area so as to buffer and reflect the vibration wave of the excavation blasting and control the damage influence of the vibration wave on the reserved rock mass, and the smooth excavation contour is obtained by the blasting technology, namely the presplitting blasting. The presplitting blasting is widely applied to vertical and inclined excavation wall surfaces; presplitting blasting is also adopted on regular curved surfaces, twisted curved surfaces, horizontal base surface building and the like. Therefore, the influence range of rock mass damage of the reserved area can be controlled by adopting the pre-splitting blasting, and the integrity and stability of the reserved area can be effectively protected. The presplitting blasting is suitable for weak rock formations with poor stability and requirements on controlling excavation profiles.

The existing pre-splitting hole blasting adopts simultaneous initiation, but the simultaneous initiation of the pre-splitting holes has large blasting vibration, and in many open-air deep-hole high-step blasting operations, the integrity of surrounding rock masses needs to be protected, and the workload is controlled; and a smooth rock wall surface is obtained, and overbreak is reduced; so that the simultaneous detonation of the pre-cracked ore cannot meet the current engineering requirements.

Disclosure of Invention

The invention provides a method for conducting hole-by-hole initiation presplitting blasting to form a seam in an open-air deep hole step presplitting blasting process under a complex environment, aiming at the characteristics that in the presplitting blasting of the open-air deep hole step under the complex environment, the step or the side slope of an open-air mine has high fall, steep slope angle and high weathering degree, and the stability of surrounding rocks and building structures under the complex environment need to be considered.

The method carries out presplitting blasting along the final boundary line of the step blasting, namely the design contour line, the presplitting hole is initiated more than 100ms before the main blasting hole, a crack is pre-blasted between the main blasting hole and the protected rock mass, after the presplitting is formed, the blasting buffer blasting hole group and the main blasting hole group are initiated, the presplitting can reduce the blasting earthquake effect of the main blasting hole group, the damage to the surrounding rock mass is slight, the integrity of the rock mass is protected, and the workload is reduced.

The delay time of the detonators in the holes is required to be set in advance for the digital electronic detonators, and when accurate short-delay detonation is carried out layer by layer or hole by hole, the edge stress distribution of the edges of the blast holes is changed through the time difference, so that the stress of the blast holes is concentrated, cracks are expanded and communicated in the direction of the blast hole connecting line, and the vibration is effectively reduced compared with simultaneous blasting.

The technical scheme adopted by the invention for solving the technical problem is as follows:

a method for initiating and presplitting blasting crack formation of an open-air deep hole step presplitting hole by hole under a complex environment comprises the following specific steps:

(1) uniformly arranging inclined pre-splitting holes on the outline of the foundation pit excavated by the open-air deep hole step in a complex design environment, and arranging axial uncoupled air spaced charging devices in the pre-splitting holes;

(2) a plurality of rows of main blasting holes are arranged in a main blasting area of a foundation pit excavation surface, the row spacing of the main blasting holes is equal, the hole spacing of the main blasting holes is equal, a row of buffer holes are arranged between the main blasting holes and the pre-cracking holes, the direction angles of the buffer holes and the pre-cracking holes are the same, axial uncoupled air spaced charging devices are arranged in the buffer holes and the main blasting holes,

(3) the axial uncoupled air spaced explosive charging device in the pre-splitting hole controls accurate delay hole-by-hole detonation through a digital electronic detonator;

(4) the axial uncoupled air spaced charging device of the buffer hole controls accurate delay hole-by-hole detonation through a digital electronic detonator;

(5) the axial uncoupled air spaced explosive charging device in the main explosion hole controls accurate delay to detonate row by row and hole by hole through a digital electronic detonator; and the pre-crack hole, the buffer hole and the main explosion hole are sequentially detonated to form the pre-crack.

The aperture of the pre-splitting hole is 50-200 mm, the hole spacing of the pre-splitting hole is 8-12 times of the diameter of the pre-splitting hole, and the delay time of the digital electronic detonator of the pre-splitting hole is 8-12 ms; the horizontal distance between the pre-cracked holes and the orifices of the adjacent rows of main blasting holes is 3-3.5 m, and the horizontal distance between the pre-cracked holes and the bottoms of the adjacent rows of main blasting holes is 2.5-3 m.

The aperture of the buffer hole is 50-200 mm, the distance between the buffer hole and the pre-splitting hole is 2-4 m, and the hole distance between the buffer holes is 4-5 m; loose slag with the height of 1-1.5 m is filled at the bottom of the buffer hole, the delay time of the pre-splitting hole and the buffer hole is 100-200 ms, and the delay time of the buffer hole and the adjacent row of main blast holes is 12-25 ms.

The hole interval of each row of main blast holes is 8-12 times of the aperture of the main blast holes, the row interval of the main blast holes in adjacent rows is 1-1.2 times of the hole interval of the main blast holes, the inter-hole delay time of the digital electronic detonators in the main blast holes is 25-75 ms, the inter-row delay time of the digital electronic detonators in the main blast holes is 50-400 ms, the drilling inclination angle of the main blast hole row and the row is 0-30 degrees, and the drilling inclination angle of the main blast hole row and the row is the same or different.

Further, the main blast hole is a vertical deep hole (see fig. 5).

The complex environment is that civil houses, cultural relics and other surrounding building structures are arranged in the range of 100m around the explosion area.

The digital electronic detonator is an electric detonator which controls the detonation process by adopting an electronic control module, wherein the electronic control module is a special circuit module which is arranged in the digital electronic detonator, has the functions of controlling the detonation delay time and the detonation energy of the detonator, is internally provided with a detonator identity information code and a detonation password, can test the self function and performance and the electrical performance of a detonator ignition element, and can communicate with a detonation controller and other external control equipment.

The digital electronic detonator is a commercially available product;

the electronic detonator can be selected from a strong detonator MFB-50, a CZQBQ-50, a 90, a 150, a 200 type and the like.

Preferably, the axial non-coupling air spaced charges of the pre-splitting holes and the buffer holes adopt the axial non-coupling air spaced charges in the literature 'corundum (gold) open-pit metal mine pre-splitting blasting technology' (see fig. 2);

preferably, the axial non-coupling air spaced charge of the main blasting hole adopts the axial non-coupling air spaced charge in the literature "exploring open stope high step side slope deep hole presplitting blasting technology" (see fig. 4);

the delay time between main blast holes and the delay time between main blast hole rows of the main blast area are determined according to the rock mechanical property of the main blast area;

the invention has the beneficial effects that:

according to the invention, through design optimization of blasting parameters such as the diameter of blast holes, the hole pitch, the row pitch, the loading amount and the like, and design of an initiation system, delay time is selected, hole-by-hole initiation is realized, and pre-cracks are formed; compared with the simultaneous initiation of the pre-splitting holes, the method for initiating the pre-splitting blasting to form the joint by the pre-splitting holes of the open deep hole step by the pre-splitting hole initiation to initiate the open steps by the method for initiating the pre-splitting blasting to form the joint by the pre-splitting holes of the open deep hole step, the pre-joint can reduce the blasting earthquake effect of the main blasting hole group in a certain range, the damage to the surrounding rock mass is slight, the integrity of the rock mass is protected, the vibration to the surrounding civil houses, cultural relics and other surrounding structures is small, the disturbance of the reserved rock mass is small, the stability is good; the smooth rock wall surface can be obtained, the overbreak is greatly reduced, and the stability of surrounding rocks is kept.

Drawings

FIG. 1 is a diagram of blast hole arrangement and pre-splitting blasting effect;

FIG. 2 is a schematic view of an axially decoupled air-spaced charge configuration for a pre-split hole and a buffer hole;

FIG. 3 is a schematic cross-sectional view of a blast hole arrangement;

FIG. 4 is a schematic diagram of a main charge configuration;

FIG. 5 is a schematic view of a vertical deep hole of a main blast hole.

Detailed Description

The present invention will be further described with reference to the following embodiments.