Static excavation method for large-section hard rock water delivery tunnel in urban highly built-up area

Abstract

The invention relates to the technical field of municipal construction, in particular to a static excavation method for a large-section hard rock water delivery tunnel in an urban highly built-up area, which comprises the following steps of: dividing a tunnel face into an upper excavation area and a lower excavation area; the upper excavation area is excavated firstly, and after one excavation cycle of the upper excavation area is completed, the upper excavation area and the lower excavation area are excavated synchronously; the excavation of the upper excavation area comprises the following steps: marking an excavation contour line, drilling a contour hole along the contour line, drilling a transverse cleavage hole, inserting cleavage rods into the contour hole and the transverse cleavage hole, starting cleavage operation, and cleaning rocks; the excavation of the lower excavation area comprises the following steps: marking an excavation contour line, drilling a contour hole, drilling an expansion hole, filling the expansion hole and the contour hole with an expanding agent, enabling the expanding agent to react to generate expansive force to cause the rock mass in the lower excavation area to be broken, and then removing slag. According to the method, noise pollution and vibration hazards can be avoided, excavation is conducted synchronously up and down, the process connection efficiency is improved, and then the construction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of municipal construction, and in particular to a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city. Background Art

[0002] In the wave of rapid urbanization, the demand for water resources in cities has shown an unprecedented growth trend. With the continuous concentration of population and rapid economic development, the management and allocation of urban water resources has become a major issue related to people's well-being and sustainable social development. Traditional surface water diversion methods, such as river diversion and open channel construction, not only occupy a large amount of precious land resources, but also may cause irreversible damage to the original ecological environment, especially in highly built-up areas of cities, where land resources are scarce and the environmental carrying pressure is huge. These traditional methods can no longer meet the needs of modern cities for efficient, safe and environmentally friendly allocation of water resources.

[0003] Therefore, underground water tunnels have gradually emerged as an innovative solution and have been widely used. As a special tunnel project, water tunnels have significant advantages: they can avoid complex geological structures and unfavorable terrain conditions, ensuring the safety and stability of water flow during transportation; at the same time, their structure is simplified, the footprint is small, and the impact on the surface environment is minimized, which meets the requirements of modern cities for environmental protection and sustainable development. In water resource allocation, hydropower station construction and various water conservancy projects, water tunnels play a vital role and become an important link between water sources and water use areas.

[0004] However, the construction of large-section hard rock water tunnels in highly built-up areas of cities is an extremely challenging task. These areas are usually located in the center or periphery of the city, with dense buildings, complex underground infrastructure, and extremely harsh construction environments. The geological conditions in hard rock areas are complex and changeable, the rock is hard and has developed joints, which makes construction difficult and risky. Although traditional excavation methods, such as drilling and blasting, can meet construction needs to a certain extent, the noise pollution and vibration hazards they generate have a serious impact on the surrounding environment. In highly built-up areas of cities, these impacts are particularly prominent, not only interfering with the normal lives of surrounding residents, but also posing a threat to the safety of surrounding buildings and underground infrastructure.

[0005] Specifically, the drilling and blasting method generates strong noise and vibration during the construction process, which poses a potential threat to the structural safety of surrounding buildings and may even cause damage to the buildings. At the same time, the dust and exhaust gas generated by the drilling and blasting method will also pollute the environment and affect the health and quality of life of surrounding residents. In addition, the construction efficiency of the drilling and blasting method is relatively low, and it consumes a lot of time and resources, which is difficult to meet the needs of modern cities for fast and efficient construction.

[0006] In view of the above problems, an innovative static excavation method for large-section hard rock water conveyance tunnels in highly built-up urban areas was proposed. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area in an urban area. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area in an urban area divides the entire heading into an upper excavation area and a lower excavation area. The upper excavation area is excavated by drilling and splitting, and the lower step is excavated by static expansion, thereby avoiding noise pollution and vibration hazards. In addition, the upper and lower excavations are carried out synchronously, thereby improving the process connection efficiency, thereby greatly improving the construction efficiency.

[0008] The technical solution of the present invention is as follows:

[0009] A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area comprises the following steps: dividing the tunnel face into an upper excavation area and a lower excavation area; first excavating the upper excavation area, and when the upper excavation area completes an excavation cycle, excavating the upper excavation area and the lower excavation area synchronously;

[0010] The excavation steps of the upper excavation area are as follows: marking the excavation contour line of the upper excavation area on the tunnel face, drilling contour holes along the contour line to create an open face, then drilling transverse splitting holes on the tunnel face of the upper excavation area, inserting splitting rods into the contour holes and transverse splitting holes of the upper excavation area, starting the splitting operation to split the rock mass of the upper excavation area, clearing the rock, and exposing the step surface on the top of the lower excavation area;

[0011] The excavation steps of the lower excavation area are as follows: marking the excavation contour line of the lower excavation area on the tunnel face, drilling contour holes along the contour line, drilling expansion holes downward on the step surface exposed at the top of the lower excavation area, filling the expansion holes and contour holes of the lower excavation area with expansion agent, the expansion agent reacts to generate expansion force to cause the rock mass in the lower excavation area to break, and then clear the slag;

[0012] By dividing the tunnel face into an upper excavation area and a lower excavation area and carrying out excavation in sequence, zoning management of excavation operations is achieved, effectively improving construction efficiency; after completing an excavation cycle in the upper excavation area, the lower excavation area is excavated simultaneously, further optimizing the construction process and reducing construction time; at the same time, this method avoids the noise pollution and vibration hazards caused to the surrounding environment by traditional high-vibration excavation methods, such as drilling and blasting, and is suitable for areas with high environmental requirements such as highly built-up areas in cities.

[0013] The contour holes can be arranged in a meshing or spaced arrangement along the contour line; this can effectively control over-break and under-break and improve excavation accuracy; the meshing arrangement can ensure the accuracy of the tunnel contour line, while the spaced arrangement can reduce the total number of holes drilled, save drilling time and improve construction efficiency; the specific hole layout method can be flexibly set according to the site conditions to adapt to different geological conditions and construction requirements.

[0014] The contour holes and transverse splitting holes in the upper excavation area are drilled by a water-grinding drill, while the contour holes and expansion holes in the lower excavation area are drilled by a pneumatic pick. The contour holes and transverse splitting holes in the upper excavation area are drilled by a water-grinding drill to ensure the accuracy and efficiency of drilling. The water-grinding drill has the advantages of fast drilling speed and good drilling quality, and is suitable for drilling operations in hard rock formations. The contour holes and expansion holes in the lower excavation area are drilled by a pneumatic pick, which can reduce the drilling cost and improve the construction economy. The combined use of this drilling method not only ensures the construction efficiency, but also controls the construction cost.

[0015] The splitting direction of the splitting rod is different each time; it can generate cracks of different inclinations on the rock, increase the degree of rock crushing, and facilitate slag removal operations; the flexibility of this splitting method enables construction personnel to adjust the splitting direction according to the actual situation of the rock to achieve the best crushing effect.

[0016] The angle between two adjacent splitting directions of the splitting rod ranges from 0° to 180°, providing construction personnel with a wider range of splitting direction options; this flexibility helps to adapt to different rock structures and textures, improve splitting efficiency, and reduce energy loss during the splitting process.

[0017] Arc-shaped pads are arranged in the contour holes and transverse splitting holes in the upper excavation area, and the plunger of the splitting rod is pressed against the inner wall of the hole through the arc-shaped pads; the splitting stroke and splitting range can be increased, and the drilling efficiency can be further improved; the design of the arc-shaped pads enables the plunger of the splitting rod to fit more closely to the inner wall of the hole, thereby more effectively transmitting the splitting force and improving the splitting effect.

[0018] An inclined hole for wedges is drilled on the tunnel face in the area enclosed by every four transverse splitting holes, and excavation is carried out by inserting wedges into the inclined holes for wedges; wedges can be used to assist in small-scale splitting and excavation. This method can gradually decompose the rock, improve the efficiency of slag discharge, and reduce the dependence on large-scale machinery and equipment, thereby reducing construction costs.

[0019] The contour holes in the lower excavation area are inclined holes, which can reduce the over-excavation area and improve the excavation accuracy. The design of the inclined holes makes the drilling direction form a certain angle with the tunnel axis, making it easier to control the accuracy of the excavation contour line. At the same time, the inclined holes can also reduce vibration and noise during the drilling process, and have less impact on the surrounding environment.

[0020] When the lower excavation area is excavated to the position of the arch foot, arch foot expansion straight holes and arch foot expansion inclined holes are drilled on the top step surface of the lower excavation area and the palm surface of the lower excavation area. The arch foot expansion inclined holes are close to the contour surface, which can more effectively control the over-excavation and under-excavation phenomena. The arch foot expansion inclined holes are close to the contour surface, making drilling easier, and the expansion generates a force that is nearly perpendicular to the contour surface, further improving the excavation accuracy and construction quality.

[0021] The inclination angle of the expansion inclined hole of the arch foot is greater than 45° and less than 90°; it can ensure that the expansion agent generates sufficient expansion force in the hole to crush the rock; at the same time, the design of this inclination angle can also make the expansion force produce a component in the horizontal direction, which is helpful to dig out the rock and complete short-distance excavation or surface finishing; it not only ensures construction efficiency, but also improves construction safety.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention discloses a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city avoids the noise pollution and vibration hazards caused by traditional high-vibration excavation methods (such as drilling and blasting methods), and meets the strict requirements of highly built-up areas of cities on environmental protection and quality of life of residents; the static excavation method reduces the safety risks in the construction process, especially in an urban environment with dense surrounding buildings and complex infrastructure, and can significantly reduce the impact of construction on surrounding structures and ensure construction safety.

[0024] 2. The present invention discloses a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city divides the heading into an upper excavation area and a lower excavation area, and adopts a strategy of excavating up first and then down, and excavating synchronously, thereby optimizing the construction process and improving the efficiency of process connection. The upper excavation area adopts a drilling and splitting method, and the lower excavation area adopts a static expansion method. The two excavation methods complement each other and greatly improve the construction efficiency.

[0025] 3. The present invention discloses a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city. In the static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city, the contour holes are arranged in an interlocking or spaced arrangement along the contour line, and the design of inclined holes and arch foot expansion inclined holes is adopted, which effectively controls the over-excavation and under-excavation phenomena and improves the construction quality; the change of the splitting direction of the splitting rod and the use of arc-shaped pads and wedges further enhance the rock crushing effect, which is conducive to the precise control of the excavation contour.

[0026] 4. The present invention discloses a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city is not only applicable to a single rock tunnel, but also to complex geological conditions such as upper soft and lower hard strata or upper hard and lower soft strata, and has strong adaptability and flexibility. By adjusting the hole layout and excavation sequence, targeted construction can be carried out according to the characteristics of different strata to ensure smooth construction.

[0027] 5. The present invention discloses a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city reduces material consumption and energy consumption during the construction process, thereby reducing construction costs. Compared with traditional excavation methods, the present method is more in line with the requirements of sustainable urban development, and is conducive to protecting the urban ecological environment and promoting the development of green buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall drilling arrangement of a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city according to an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​an urban area according to an embodiment of the present invention, in which contour holes are opened on the contour line of the upper excavation area and transverse splitting holes are opened on the tunnel face of the upper excavation area;

[0030] Figure 3 A schematic diagram of an inclined hole for wedges to be opened on an upper excavation area of ​​a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of providing arc-shaped pads on both sides of the plunger of a splitting rod in a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city according to an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of different forces applied to a splitting rod in a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​a city according to an embodiment of the present invention;

[0033] Figure 6 A schematic diagram of the force of the arch foot expansion inclined hole in a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​an urban area according to an embodiment of the present invention;

[0034] Figure 7 A schematic diagram of providing an arch foot expansion straight hole and an arch foot expansion inclined hole at the arch foot of the lower excavation area of ​​a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​an urban area according to an embodiment of the present invention;

[0035] Figure 8 It is a schematic diagram of an upper soft and lower hard stratum of a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up area of ​​an city according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0037] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0038] With the acceleration of urbanization, the demand for water resources in cities is growing. In highly built-up areas of cities, traditional surface water diversion methods are often restricted by land resource limitations and environmental impacts. Therefore, underground water tunnels have become an effective solution. Water tunnels are tunnel projects used to guide water flow or transport water resources. They can avoid adverse geological and topographic conditions, are safe and convenient, adapt to the special requirements of high-velocity pressureless tunnels, have simplified structures and occupy less space. They play a vital role in water resource allocation, hydropower station construction and water conservancy projects. However, there are many technical difficulties in its underground construction, especially in hard rock areas, where the construction difficulty and risk are further increased. In addition, due to the dense buildings and complex infrastructure in urban areas, traditional high-vibration excavation methods, such as drilling and blasting, may cause unacceptable noise pollution and other damage to the surrounding environment, resulting in restrictions on their use.

[0039] Reference Figures 1 to 7 , a static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area, comprising the following steps:

[0040] Divide the tunnel face into an upper excavation area 2 and a lower excavation area 6;

[0041] First, the upper excavation area 2 is excavated. When the upper excavation area 2 completes an excavation cycle, the upper excavation area 2 and the lower excavation area 6 are excavated synchronously;

[0042] The excavation steps of the upper excavation area 2 are as follows: marking the excavation contour line of the upper excavation area 2 on the tunnel face, then drilling a contour hole 1 along the contour line to create an open face, then drilling a transverse splitting hole 7 on the tunnel face of the upper excavation area 2, inserting a splitting rod 102 into the contour hole 1 and the transverse splitting hole 7 of the upper excavation area 2, starting the splitting operation to split the rock mass of the upper excavation area 2, clearing the rock, so that the top of the lower excavation area 6 is exposed to the step surface 5;

[0043] The excavation steps of the lower excavation area 6 are as follows: mark the excavation contour line of the lower excavation area 6 on the face, then drill contour holes along the contour line, drill expansion holes 3 downward on the step surface 5 exposed at the top of the lower excavation area 6, fill the expansion holes 3 and contour holes of the lower excavation area 6 with expansion agent, the expansion agent reacts to generate expansion force, causing the rock mass of the lower excavation area 6 to be broken, and then the slag is cleared.

[0044] The present application divides the entire face into an upper excavation area 2 and a lower excavation area 6. The upper excavation area 2 is excavated by drilling and splitting, and the lower step is excavated by static expansion, thereby avoiding noise pollution and vibration hazards. In addition, the upper and lower excavations are carried out synchronously to improve the process connection efficiency, thereby greatly improving the construction efficiency.

[0045] A detailed survey is required before excavation. The survey requires a detailed understanding of the geological conditions, hydrogeology, surrounding buildings and environmental factors, and the vibration control section during the excavation process, with a focus on the geological conditions, hydrogeology, surrounding buildings and environmental factors of the vibration control section. Then, based on the results of the survey, the entire water diversion tunnel face is divided into two areas, and the hole layout is designed based on factors such as rock conditions and face size.

[0046] According to the set excavation method, prepare the corresponding equipment and materials, such as water-grinding drill, pneumatic pick, splitting rod 102, static expansion agent, etc., and debug and test the equipment to ensure that it can work properly. Provide professional training for construction personnel to ensure that they are familiar with construction technology and safety regulations. Before construction, the face needs to be thoroughly cleaned to remove all loose rock debris and soil to ensure the cleanliness of the work area. Check the flatness of the face, and use wedges to trim any uneven or protruding parts in advance to ensure that the drill bit can smoothly enter the rock formation when drilling, and sort out the debris near the face to ensure the space of the working surface. Establish the infrastructure required for construction, such as temporary roads, power supply, water source, etc. In addition, it is necessary to install monitoring equipment to monitor the geological changes, structural safety and noise decibels during the construction process in real time to ensure construction safety and reduce the impact of construction on the environment.

[0047] Before the splitting operation in the upper excavation area 2 is carried out, all personnel must be evacuated outside the warning area, and the splitting operation can only be carried out after the construction personnel have checked and confirmed that no personnel remain in the dangerous area. During the splitting process, it is necessary to pay attention to the pressure gauge of the oil pump. Once the pressure gauge reaches 120MPa, it means that the splitting work is completed. Subsequently, the pressure can be released and the splitting rod 102 can be removed, and the split rock mass can be peeled off by an excavator, and then the slag can be cleaned up uniformly.

[0048] Before construction in the lower excavation area 6, the amount of expansion agent added is calculated according to the material and engineering requirements, and the expansion agent and water are fully mixed on site using a bucket and a stirrer. After mixing, the mixture is injected into the expansion hole 3 and the contour hole 1, and the holes are sealed with waterproof plastic film and the like. The reaction takes 6-7 hours. During this period, the construction personnel use cameras and on-site recording to monitor the progress, and the expansion agent reacts to generate expansion force to break the rock.

[0049] In addition, after the expansion is completed, a blasting machine is used to further break up the rock, and a loader or excavator is used to clean up the divided rock.

[0050] After the operation is completed, the splitting effect and expansion effect need to be evaluated. For areas where the splitting effect is not ideal, a secondary splitting operation is required, and for areas where the expansion effect is not ideal, a secondary static expansion operation is required to ensure that the splitting and crushing effects meet the slag discharge requirements.

[0051] In some embodiments, the contour holes are arranged in a meshed or spaced arrangement along the contour line.

[0052] When the hole arrangement is designed to be interlocked, the contour holes intersect with each other, but the intersection range is as small as possible to reduce the total number of holes drilled. Interlocking holes are usually used to shape the tunnel contour or create an air surface for the first time. The number of interlocking holes is closely related to the aperture. The larger the aperture, the fewer the total number of holes. However, as the aperture increases, the time required for single hole drilling will also increase. Therefore, in practical application projects, an economic balance should be found between the aperture and the drilling time according to the actual situation.

[0053] Interval hole arrangement means that there is a certain distance between adjacent holes, which is different from the interlocking hole arrangement. The purpose of interval hole arrangement is to reduce the total number of holes to save drilling time, but the distance between holes needs to be controlled to avoid the situation where the holes cannot be split. In actual application engineering, the design should be based on the actual situation. When forming the tunnel contour line, the distance between adjacent holes is increased to form a polygonal contour section, and then backfill is performed to form the designed section.

[0054] The interlocking hole arrangement method can effectively control the over-excavation and under-excavation phenomenon, and the interlocking hole arrangement method and the intermittent hole arrangement method can effectively improve the construction efficiency. The specific hole arrangement method can be set according to the site conditions.

[0055] like Figure 2 As shown, the contour line 1 of the upper excavation area 2 of the present application is a bite-in arrangement.

[0056] In some embodiments, the contour holes 1 and the transverse splitting holes 7 of the upper excavation area 2 are drilled by a water-grinding drill, and the contour holes 1 and the expansion holes 3 of the lower excavation area 6 are drilled by a pneumatic pick.

[0057] In order to further improve the splitting efficiency, in some embodiments, the splitting rod 102 changes the splitting direction after each splitting is completed, so as to generate cracks with different inclinations on the rock.

[0058] Specifically, Figure 5 As shown, after the splitting rod 102 applies a force in the splitting direction 106 in the splitting hole to split, the splitting rod 102 is adjusted so that the splitting rod 102 applies a force in the splitting direction 108 in the splitting hole, which can further increase the generation of cracks, thereby increasing the degree of crushing, which is beneficial to the slag removal operation. When the splitting direction is set to the splitting direction 106, the inner wall of the borehole is subjected to a vertical load 107, thereby generating a vertical crack 111. When the splitting direction is set to the splitting direction 2 108, the inner wall of the borehole is subjected to a horizontal load 108, thereby generating a horizontal crack 110.

[0059] The splitting directions of the two adjacent splitting rods 102 are arbitrarily selected from 0° to 180°.

[0060] Reference Figure 4 In some embodiments, arc-shaped pads 104 are provided in the contour hole 1 of the upper excavation area 2 and the transverse splitting hole 7, and the plunger 103 of the splitting rod 102 is pressed against the inner wall of the hole through the arc-shaped pads 104. The arc-shaped pads 104 can increase the splitting stroke and splitting range, further improving the drilling efficiency.

[0061] In some embodiments, an inclined hole 203 for a wedge is drilled on the tunnel face of the area enclosed by every four transverse splitting holes 7, and excavation is performed by inserting a wedge into the inclined hole 203 for a wedge. In this way, a wedge can be used to assist in small-scale splitting and excavation, and the rock blocks can be split from the tunnel face in combination with the splitting cracks 202 between two adjacent splitting holes, and can be made to fall using other tools such as a crowbar, so that the rock can be gradually decomposed and the slag removal efficiency can be improved.

[0062] In some embodiments, the contour holes of the lower excavation area 6 are inclined holes, which can reduce the over-excavation and under-excavation areas.

[0063] Reference Figure 7 In some embodiments, when the lower excavation area 6 is excavated to the position of the arch foot, an arch foot expansion straight hole 301 is drilled on the top step surface 5 of the lower excavation area 6 and the palm surface of the lower excavation area 6. Its subsequent use is no different from the previous one. However, considering the influence of the clearance and the over-excavation and under-excavation phenomenon, an arch foot expansion inclined hole 302 is drilled at a position close to the contour surface 303, which makes drilling easier, and the expansion generates a force that is nearly perpendicular to the contour surface, thereby controlling the over-excavation and under-excavation phenomenon.

[0064] In some embodiments, the inclination angle 305 of the abutment expansion oblique hole 302 is greater than 45° and less than 90°.

[0065] Reference Figure 6 When the arch foot expansion inclined hole 302 is expanded and fractured, the inside of the arch foot expansion inclined hole 302 is subjected to the expansion force 306 of the arch foot expansion inclined hole 302, and the expansion force 306 of the arch foot expansion inclined hole 302 can be decomposed into a vertical component of the expansion force 307 and a horizontal component of the expansion force 308. The horizontal component of the expansion force 308 is used to dig out the rock to complete short-distance excavation or surface finishing.

[0066] Reference Figure 8In actual engineering, not all water tunnels are single soil tunnels or rock tunnels. Often, the two coexist, forming an upper soft and lower hard stratum or an upper hard and lower soft stratum. Compared with a single rock tunnel, the soft layer 9 can be cleared by an excavator, etc. In this way, it is relatively simple to create an open surface. Compared with a single rock tunnel, its excavation method and excavation sequence are very different. When the upper part is a soft layer 9, an excavator is first used to gradually hollow out the upper part and remove the slag. Then, the contour hole 1 is arranged according to the boundary 10 between the soft and hard layers, and then the contour hole 1 is split to form a contour line, and the top of the lower excavation area 12 is leveled to facilitate the excavation of the lower excavation area.

[0067] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0068] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area, characterized in that: The following steps are involved: The tunnel face is divided into an upper excavation area and a lower excavation area; the upper excavation area is excavated first, and when the upper excavation area completes an excavation cycle, the upper excavation area and the lower excavation area are excavated synchronously; The excavation steps of the upper excavation area are as follows: marking the excavation contour line of the upper excavation area on the tunnel face, drilling contour holes along the contour line to create an open face, then drilling transverse splitting holes on the tunnel face of the upper excavation area, inserting splitting rods into the contour holes and transverse splitting holes of the upper excavation area, starting the splitting operation to split the rock mass of the upper excavation area, clearing the rock, and exposing the step surface on the top of the lower excavation area; The excavation steps of the lower excavation area are as follows: mark the excavation contour line of the lower excavation area on the heading face, drill contour holes along the contour line, drill expansion holes downward on the step surface exposed at the top of the lower excavation area, fill the expansion holes and contour holes of the lower excavation area with expansion agent, the expansion agent reacts to generate expansion force to cause the rock mass in the lower excavation area to break, and then clear the slag.

2. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 1, characterized in that: The contour holes are arranged in a bite-shaped manner or at intervals along the contour line.

3. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 1, characterized in that: The contour holes and transverse splitting holes in the upper excavation area were drilled using a hydraulic drill, while the contour holes and expansion holes in the lower excavation area were drilled using a pneumatic pick.

4. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 1, characterized in that: The splitting direction of the splitting bar is different each time.

5. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 4, characterized in that: The angle range between two adjacent splitting directions of the splitting rod is 0° to 180°.

6. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 1, characterized in that: Arc-shaped pads are arranged in the contour holes and the transverse splitting holes in the upper excavation area, and the plungers of the splitting rods are pressed against the inner walls of the holes through the arc-shaped pads.

7. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 1, characterized in that: Inclined holes for wedges are drilled on the face of the area enclosed by every four transverse splitting holes, and excavation is carried out by inserting wedges into the inclined holes.

8. The static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 1, characterized in that: The contour holes in the lower excavation area are inclined holes.

9. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 8, characterized in that: When the lower excavation area is excavated to the position of the arch foot, arch foot expansion straight holes and arch foot expansion inclined holes are drilled on the top step surface of the lower excavation area and the heading surface of the lower excavation area, wherein the arch foot expansion inclined holes are close to the contour surface.

10. A static excavation method for a large-section hard rock water conveyance tunnel in a highly built-up urban area as claimed in claim 9, characterized in that: The inclination angle of the expansion inclined hole of the arch foot is greater than 45° and less than 90°.

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