Hard rock blasting construction method for semi-covered excavation of subway station in urban complex environment

Abstract

The invention belongs to the field of engineering construction, and particularly relates to a hard rock blasting construction method for a semi-cover excavation subway station in an urban complex environment, which comprises the following steps of: accurately designing blasting parameters (small row pitch, small hole pitch and less charge) and a hole-by-hole blasting technology, and combining multiple safety measures such as physical partition, dust fall spraying and vibration reduction ditches; and efficient, safe and environment-friendly construction under hard rock geological conditions in urban dense areas is realized. According to the method, the construction efficiency is remarkably improved, the construction cost is reduced, the blasting vibration velocity and environmental pollution are effectively controlled, the safety of constructors and surrounding residents is guaranteed, high technical flexibility and innovativeness are shown, and powerful technical support is provided for rapid and safe construction of similar projects such as urban subway stations.

Description

Technical Field

[0001] The invention belongs to the field of engineering construction, and in particular relates to a hard rock blasting construction method for a semi-covered subway station in a complex urban environment. Background Art

[0002] With the acceleration of urbanization, subways are an important means to solve the problem of urban traffic congestion, and their construction scale is expanding. In the construction process of urban subway stations, open-cut or mechanical excavation methods are traditionally used in the face of ultra-shallow geological sections. However, these methods have many limitations in practical applications. Especially in densely populated urban areas, the open-cut method occupies a large area and has a significant impact on ground transportation and the surrounding environment; while the mechanical excavation method is inefficient under hard rock geological conditions, and long-term continuous operation can easily lead to deterioration of air quality. The equipment needs to be frequently stopped and cooled due to high temperatures, which seriously affects the construction progress.

[0003] As a construction method that combines the advantages of open-cut and cover-cut methods, the semi-cover excavation method has gradually become an important choice for urban subway station construction. This method divides the station into two parts for construction. First, excavate and construct a part of the cover to restore ground traffic, and then excavate the remaining part and construct the station structure under the cover, effectively reducing the impact of construction on ground traffic and the surrounding environment. However, under hard rock geological conditions, the construction difficulty of the semi-cover excavation method increases significantly. Mechanical excavation is extremely inefficient in hard rock and is prone to cause continuous vibration and noise pollution to the surrounding environment.

[0004] In response to the above problems, preliminary explorations have been conducted at home and abroad on the hard rock blasting construction technology for semi-covered excavated railway stations, but relevant experience and technical specifications are still incomplete. Especially in complex urban environments, how to ensure the safety and efficiency of blasting construction while reducing the impact on surrounding buildings (structures) and residents' lives has become a technical problem that needs to be solved urgently. Therefore, the development of a set of efficient, safe, and environmentally friendly technical solutions suitable for the hard rock blasting construction of semi-covered excavated railway stations has important practical significance and application value. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a hard rock blasting construction method for semi-covered subway stations in complex urban environments. Through innovative blasting construction technology and strict safety control measures, the technical difficulties in the hard rock construction of semi-covered stations are solved, providing strong support for the rapid and safe construction of urban subway stations.

[0006] To achieve the above object, the present invention provides the following technical solution: A hard rock blasting construction method for a semi-covered subway station in a complex urban environment, comprising the following steps:

[0007] a. Divide the station into two parts, first excavate half of the station to the bottom of the cover slab, then construct the cover slab, and backfill the cover slab to restore ground traffic;

[0008] b. Carry out half-cover excavation construction in the underground space where the cover slab has been constructed to form an underground space;

[0009] c. Construction of station structures in underground space, including underground structures, station halls and platforms;

[0010] d. Use loosening blasting construction technology to excavate hard rock. The loosening blasting process adopts special blasting design to control the distance of blasting flying rocks. The blasting holes are constructed by hole-by-hole detonation with small row spacing, small hole spacing and less charge. During the blasting process, the charge amount of each hole and the maximum charge amount of simultaneous explosion are strictly controlled to control the blasting vibration speed within 0.3cm / s;

[0011] e. Use the blasting vibration speed monitoring system to monitor the blasting vibration speed to ensure that the blasting vibration speed is controlled within the design range.

[0012] Optionally, the drilling and blasting parameters of the loosening blasting construction include: blasthole diameter d=50mm, blasting step height H=1.8m, extra depth h=0.2m, blasthole depth L=H+0.2=2.5m, chassis resistance line w1=(0.4~1)H, blasthole spacing a=(1~2)w1, blasthole row spacing b=0.87a, blockage length Lfill=(20~30)d, single hole charge Q=q×a×b×H, where q is the unit explosive consumption of sandstone, which is adjusted according to actual conditions.

[0013] Optionally, before blasting construction, a physical partition shed is arranged above the open excavator to physically isolate the noise and smoke from the blasting, and then dust reduction sprays are set up in the foundation pit for dust reduction treatment.

[0014] Optionally, before blasting construction, a 2m wide vibration reduction trench is excavated around the foundation pit by mechanical and manual methods. The depth of the vibration reduction trench exceeds the blasting excavation depth to ensure that the blasting vibration speed can only propagate underground; the surface of the blasting site is covered with flexible materials and a cover plate to ensure that the blasting noise does not spread outward.

[0015] Optionally, the safety warning range during blasting construction is set to 200m, and comprehensive protection is adopted for blasting and construction equipment that cannot be evacuated on site; the blasting point is fully covered with steel plates, and the cover plate columns within the surrounding impact range are wrapped with quilts, rubber sheets, bamboo springboards, etc. to prevent them from being damaged by flying stones;

[0016] Optionally, strictly control the charge amount of a single hole and the charge amount for a single explosion to ensure the quality of hole plugging, and preset a detonation time difference interval of 25ms between holes or between groups to ensure that no flying rocks or rolling stones injure people or property.

[0017] Optionally, the blasting point should be at least 15m away from the building to ensure the safety of the blasting construction to the surrounding buildings.

[0018] Optionally, the method is applicable to urban subway stations or similar structural engineering projects with semi-covered and hard rock stations, especially to subway hard rock semi-covered and hard rock stations with slow mechanical excavation efficiency and complex surrounding environment.

[0019] The beneficial effects of the present invention are:

[0020] 1) Improve construction efficiency: By adopting a hole-by-hole detonation method with small row spacing, small hole spacing, and less charge, combined with precise blasting parameter design, the blasting efficiency is effectively improved, the number of holes drilled and the amount of explosives used required for a single blasting are reduced, thereby shortening the construction period and reducing construction costs.

[0021] 2) Enhance construction safety: This method strictly controls the blasting vibration speed to ensure that it is within 0.3cm / s, greatly reducing the impact on surrounding buildings (structures) and underground pipelines. At the same time, through multiple safety measures such as physical partitions, dust reduction sprays, vibration reduction trenches, and flexible material coverings, the spread of noise, smoke, and flying stones is effectively prevented, ensuring the safety of construction workers and surrounding residents.

[0022] 3) Reduce environmental impact: The semi-cover excavation method is used in densely populated urban areas to reduce interference with ground traffic and occupation of land resources. In addition, through reasonable blasting parameter design and strict environmental protection measures, noise, dust and vibration pollution during construction are effectively reduced, protecting the urban environment and ecological balance.

[0023] 4) Improve construction flexibility: This method is applicable to a variety of hard rock geological conditions, and can adjust blasting parameters and construction processes according to actual engineering needs, improving the flexibility and adaptability of the construction plan. At the same time, through real-time monitoring and data analysis, construction strategies can be adjusted in a timely manner to ensure construction quality and progress.

[0024] 5) Promote technological innovation: The implementation of this invention will promote the further development and improvement of hard rock blasting construction technology for semi-covered excavation stations, and provide strong support for technological innovation in related fields. At the same time, through the accumulation and summary of practical experience, it can provide valuable reference and reference for similar projects.

[0025] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 It is a cross-sectional schematic diagram of a half-covered excavation station of the present invention;

[0028] Figure 2 It is a schematic diagram of blasting parameters of the present invention;

[0029] Figure 3 It is a cross-sectional hole arrangement schematic diagram of the present invention;

[0030] Figure 4 It is a schematic diagram of the plane hole arrangement of the present invention. DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0032] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0033] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0034] See also Figure 1 to Figure 4This is a hard rock blasting construction method for semi-covered subway stations in complex urban environments. The subway station is located in a busy area of ​​the city with complex geological conditions and ultra-shallow hard rock formations. Due to the dense surrounding buildings and heavy traffic, traditional construction methods are difficult to meet the construction period and safety requirements, including the following steps:

[0035] Implementation steps:

[0036] 1. Construction preparation:

[0037] 1.1 Conduct detailed geological survey of the blasting area to determine key parameters such as rock type, hardness, and joint development.

[0038] 1.2 According to the results of geological investigation, the blasting parameters are designed, including blasthole diameter d = 50 mm, blasting step height H = 1.8 m, over-depth h = 0.2 m, blasthole depth L = 2.5 m, chassis resistance line w1 = (0.4 ~ 1) H, blasthole spacing a = (1 ~ 2) w1, blasthole row spacing b = 0.87a, plugging length Lfill = (20 ~ 30) d, and the single-hole charge Q is adjusted according to the unit explosive consumption q of sandstone.

[0039] 1.3 Prepare the materials and equipment required for blasting, including explosives, detonators, drilling machines, dust suppression spray systems, etc.

[0040] 2. The first phase of construction:

[0041] 2.1 Divide the station into two parts, north and south, and first excavate the southern area to the bottom of the cover slab.

[0042] 2.2 Construct the cover plate and backfill it to restore ground traffic and reduce the impact on surrounding traffic.

[0043] 3. Second phase of construction:

[0044] 3.1 In the underground space where the cover plate has been constructed, the semi-cover excavation method is used to excavate the remaining part to form the underground space.

[0045] 3.2 Carry out construction of station structures in underground space, including underground structures, station halls and platforms.

[0046] 4. Blasting construction:

[0047] 4.1 In hard rock formations, loosening blasting construction technology is used for excavation.

[0048] 4.2 Before blasting construction, a physical partition shed should be arranged above the open excavator to physically isolate the noise, smoke and dust caused by the blasting; a dust reduction spray system should be set up in the foundation pit to carry out dust reduction treatment.

[0049] 4.3 Dig a 2m wide vibration reduction trench around the foundation pit. The depth of the vibration reduction trench exceeds the blasting excavation depth to ensure that the blasting vibration speed can only propagate underground; cover the surface of the blasting site with flexible materials and cover plates to prevent noise from spreading.

[0050] 4.4 Set up a safety warning range of 200m to provide comprehensive protection for blasting and construction equipment that cannot be evacuated from the site; fully cover the blasting point with steel plates, and wrap and protect the cover columns within the surrounding impact range with quilts, rubber, bamboo springboards, etc.

[0051] 4.5 Strictly control the amount of explosives charged in a single hole and the amount of explosives for a single explosion to ensure the quality of hole plugging. Set a preset detonation time difference interval of 25ms between holes or groups to ensure that no flying rocks or rolling stones injure people or property.

[0052] 4.6 Use the blasting vibration speed monitoring system to monitor the blasting vibration speed in real time to ensure that it is within 0.3cm / s.

[0053] 5. Subsequent processing:

[0054] 5.1 After blasting, check the blasting effect in time and deal with abnormal situations such as blind shots.

[0055] 5.2 Clean and transport the rock debris produced by blasting to ensure a clean construction site.

[0056] 5.3 According to the monitoring data, timely adjust the blasting parameters and construction strategies to ensure the construction quality and progress.

[0057] Implementation effect:

[0058] The construction efficiency is significantly improved: by adopting a hole-by-hole detonation method with small row spacing, small hole spacing, and less charge, combined with precise blasting parameter design, the single blasting efficiency is increased by more than 30% compared with the traditional method, significantly shortening the construction period.

[0059] Construction safety is guaranteed: the blasting vibration speed is strictly controlled within 0.3cm / s, and the impact on surrounding buildings and underground pipelines is minimal; through multiple safety measures, the spread of noise, smoke and flying rocks is effectively prevented, ensuring the safety of construction workers and surrounding residents.

[0060] Reduced environmental impact: Semi-covered excavation construction reduces interference with ground traffic and occupation of land resources; reasonable blasting parameter design and strict environmental protection measures reduce noise, dust and vibration pollution during construction, protecting the urban environment and ecological balance.

[0061] Enhanced construction flexibility: This method is applicable to a variety of hard rock geological conditions, and can adjust blasting parameters and construction processes according to actual engineering needs, improving the flexibility and adaptability of the construction plan.

[0062] Technological innovation is promoted: The successful implementation of this embodiment provides valuable experience and technical support for the further development and improvement of hard rock blasting construction technology for semi-covered excavation stations, and promotes technological innovation in related fields.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A hard rock blasting construction method for a semi-covered subway station in a complex urban environment, characterized in that: The following steps are involved: a. Divide the station into two parts, first excavate half of the station to the bottom of the cover slab, then construct the cover slab, and backfill the cover slab to restore ground traffic; b. Carry out half-cover excavation construction in the underground space where the cover slab has been constructed to form an underground space; c. Construction of station structures in underground space, including underground structures, station halls and platforms; d. Use loosening blasting construction technology to excavate hard rock. The loosening blasting process adopts special blasting design to control the distance of blasting flying rocks. The blasting holes are constructed by hole-by-hole detonation with small row spacing, small hole spacing and less charge. During the blasting process, the charge amount of each hole and the maximum charge amount of simultaneous explosion are strictly controlled to control the blasting vibration speed within 0.3cm / s; e. Use the blasting vibration speed monitoring system to monitor the blasting vibration speed to ensure that the blasting vibration speed is controlled within the design range.

2. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claim 1 is characterized by: The drilling and blasting parameters of the loosening blasting construction include: blasthole diameter d=50mm, blasting step height H=1.8m, overdepth h=0.2m, blasthole depth L=H+0.2=2.5m, chassis resistance line w1=(0.4~1)H, blasthole spacing a=(1~2)w1, blasthole row spacing b=0.87a, blocking length Lfill=(20~30)d, single hole charge Q=q×a×b×H, where q is the unit explosive consumption of sandstone, which is adjusted according to actual conditions.

3. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claim 1 is characterized by: Before blasting construction, a physical partition shed is first arranged above the open excavator to physically isolate the noise and smoke from the blasting, and then dust reduction sprays are set up in the foundation pit for dust reduction treatment.

4. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claim 1 is characterized by: Before the blasting construction, a 2m wide vibration reduction trench is excavated around the foundation pit by mechanical and manual methods. The depth of the vibration reduction trench exceeds the blasting excavation depth to ensure that the blasting vibration speed can only propagate underground; the surface of the blasting site is covered with flexible materials and a cover plate to ensure that the blasting noise does not spread outward.

5. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claim 1 is characterized by: The safety warning range during blasting construction is set at 200m, and comprehensive protection is adopted for the blasting and construction equipment that cannot be evacuated on site; the blasting point is fully covered with steel plates, and the cover plate columns within the surrounding impact range are wrapped and protected with quilts, rubber, and bamboo springboards to prevent them from being damaged by flying rocks.

6. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claim 5 is characterized by: Strictly control the charge amount of a single hole and the amount of explosives for a single explosion to ensure the quality of hole plugging. Set a preset detonation time difference of 25ms between holes or groups to ensure that no flying rocks or rolling stones injure people or property.

7. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claim 1 is characterized by: The blasting point should be no less than 15m away from the building to ensure the safety of the surrounding buildings during the blasting construction.

8. The hard rock blasting construction method for a semi-covered subway station in a complex urban environment according to claims 1 to 7, characterized in that: The method is suitable for urban subway stations or similar structural engineering projects with semi-covered and hard rock stations, especially for subway hard rock semi-covered and hard rock stations with slow mechanical excavation efficiency and complex surrounding environment.

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