CN218716780U - Be used for hard stratum mechanical excavation to unite blasting construction structures under soft - Google Patents

Abstract

The utility model discloses a combined blasting construction structure for mechanical excavation of upper soft and lower hard strata, which comprises a construction tunnel positioned in an earth-rock grounding layer, wherein the construction tunnel is provided with an empty layer and a blasting area; the temporary hollow layer is a hole body structure formed by excavating a first excavation groove part, a second excavation groove part and a third excavation groove part in the construction tunnel in sequence, the inner wall of the hole body structure is provided with a primary support, and the blasting area comprises a climbing passage and an operation platform; the climbing channel is provided with a plurality of cut holes, a plurality of peripheral holes and a plurality of auxiliary holes, the peripheral holes are arranged on a tunnel excavation contour line, the peripheral holes are positioned on the outer sides of the auxiliary holes, and the auxiliary holes are arranged on the outer sides of the cut holes; the problems that when tunnel construction is actually carried out, the hardness of rock and soil is uneven during tunnel excavation construction in an earth-rock boundary stratum, an upper soil layer is prone to collapse when a lower weathered rock stratum is exploded, and harm is caused to constructors are solved.

Description

Mechanical excavation combined blasting construction structure for upper soft and lower hard strata

Technical Field

The utility model relates to a subway station construction technical field especially relates to a be used for hard stratum machinery excavation to unite blasting construction structures under soft.

Background

At present, the construction range of subway stations is wider and wider, the excavation section is also larger and larger, the faced construction environment is more and more complex, the shallow buried strata in partial areas of China mainly comprise miscellaneous filling soil, clay, sandy soil, granite and tuff with different weathering degrees, and the whole body presents obvious characteristics of upper softness and lower hardness, however, various different rock stratum combinations are often encountered in the construction process of subway station tunnels, and the conditions such as weak and uneven surrounding rocks, shallow buried bias landforms, soil and stone mixed geology and the like are endless. In the construction process of railway and highway tunnel engineering, the construction is greatly influenced and difficult due to the limitation and influence of geological conditions. However, when the tunnel construction is actually carried out, the hardness of the rock-soil is uneven during the tunnel excavation construction in the soil-rock boundary stratum, and the upper soil layer is easy to collapse due to the blasting of the lower weathered rock stratum, so that the problem of harm to constructors is caused.

Disclosure of Invention

The utility model provides a be used for hard stratum machinery excavation jointly to blast construction structures under soft to overcome when actually carrying out tunnel construction, there is the soft or hard inequality of ground when the earth stone boundary ground (soft under hard) in situ tunnel excavation construction, easily causes the upper portion soil layer to collapse when the blasting of lower part morals and manners rock, forms the problem of harm to the constructor.

In order to realize the purpose, the technical scheme of the utility model is that:

a combined blasting construction structure for mechanical excavation of an upper soft and lower hard stratum comprises a construction tunnel located in an earth-rock sub-grounding layer, wherein an upper pilot tunnel of the construction tunnel is provided with a blasting area formed by a temporary empty layer and a lower pilot tunnel of the construction tunnel, the temporary empty layer is located in an earth geological layer, and the blasting area is located on an earth geological layer;

the temporary hollow layer is a hole body structure formed by sequentially excavating a first excavation groove part, a second excavation groove part and a third excavation groove part in the construction tunnel, the inner wall of the hole body structure is provided with a primary support, and core soil is arranged in the temporary hollow layer;

the blasting area comprises a climbing channel and an operation platform; the core soil is positioned on the operation platform, and the climbing channel is used for the cantilever excavator to move to the operation platform and excavate the core soil to form a free surface;

the climbing channel is provided with a plurality of cut holes, a plurality of peripheral holes and a plurality of auxiliary holes, the peripheral holes are arranged on a tunnel excavation contour line, the peripheral holes are positioned on the outer sides of the auxiliary holes, and the auxiliary holes are arranged on the outer sides of the cut holes;

the undercut hole, the peripheral hole and the auxiliary hole are blast holes.

Furthermore, the undercut hole symmetry sets up and forms undercut hole group on climbing passageway, the bilateral symmetry of undercut hole group has laid two sets ofly supplementary hole, just two sets of supplementary holes are laid to the bottom of undercut hole group, all edges of the earth lay in the outside of supplementary hole.

Further, a protective layer is domes, a protective layer includes shaped steel steelframe, reinforcing bar net piece and concrete in the initial stage, reinforcing bar net piece arrange in the shaped steel steelframe both sides, the concrete fill in between shaped steel steelframe, reinforcing bar net piece and the construction tunnel inner wall, the concrete parcel shaped steel steelframe and reinforcing bar net piece, the shaped steel steelframe is by welding between the steel bow member and indulge the muscle and constitute.

Furthermore, a plurality of small advanced support conduits are uniformly distributed in the soil stratum outside the construction tunnel.

Further, the cut hole adopts the wedge undercutting, and the cut hole includes undercutting and cut hole, just the cut hole is located the one end of undercutting, and the distance of two adjacent cut holes of level setting is 800mm, and the distance of two adjacent cut holes of perpendicular setting is 300mm, and the one end distance of the adjacent cut that the level set up is 240mm.

Further, construction tunnel bottom is equipped with inverted arch structure and bottom platform, inverted arch structure is the arc, just be equipped with the filling layer between inverted arch structure and the bottom platform.

Further, the lining structure further comprises a secondary lining, wherein the secondary lining is arranged on the inner wall of the primary support layer.

Has the advantages that: the utility model provides a be used for hard stratum machinery excavation joint blasting construction structures under soft, divide into through mechanical excavation hard bottom under soft face and blast area, and then the separation of hard stratum under soft, the utility model discloses a subregion blasting mode is got rid of the soft layer in the construction tunnel through mechanical excavation to soft bottom, brings great disturbance when can avoiding the soft geological layer excavation of construction tunnel through mechanical excavation, carries out laying of porthole to the blast area on hard geological layer again, greatly reduced the vibration influence that direct blasting brought, effectively controlled because of the deformation of the soft stratum in upper portion that construction vibrations arouse and the influence to existing building.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a schematic view of a combined blasting construction structure for mechanical excavation of upper soft and lower hard strata disclosed by the utility model;

fig. 2 is a side view of the combined blasting construction structure for mechanical excavation of upper soft and lower hard strata disclosed by the utility model;

fig. 3 is a schematic diagram of a blasting area of a combined blasting construction structure for mechanical excavation of upper soft and lower hard strata disclosed by the utility model;

FIG. 4 is a monitoring value of the ground surface vibration velocity after the prior full-face blasting;

fig. 5 is the utility model discloses a monitoring value that is used for earth's surface velocity of vibration after hard stratum machinery excavation combined blasting construction structure blasting under soft.

In the figure: 1. constructing a tunnel; 11. a first excavation groove part; 12. secondly, digging a groove part; 13. thirdly, digging a groove part; 2. a blasting zone; 21. climbing a passage; 211. cutting out a slotted hole; 2111. cutting; 2112. digging out the hole; 212. peripheral eyes; 213. auxiliary eyes 22 and a working platform; 3. core soil; 4. a temporary empty layer; 5. excavating a contour line of the tunnel; 6. primary support; 7. an inverted arch structure; 71. a filling layer; 8. a bottom platform; 81. secondary lining; 10. leading the small catheter.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

The embodiment provides a combined blasting construction structure for mechanical excavation of an upper soft and lower hard stratum, as shown in fig. 1, the combined blasting construction structure comprises a construction tunnel 1 located in an earth-rock sub-grounding layer, wherein the construction tunnel 1 is provided with an adjacent empty layer 4 and a blasting area 2, the adjacent empty layer 4 is located in an earth-rock stratum, and the blasting area 2 is located on a rock-rock stratum;

the temporary hollow layer 4 is a hole body structure formed by sequentially excavating a first excavation groove part 11, a second excavation groove part 12 and a third excavation groove part 13 in the construction tunnel 1, the inner wall of the hole body structure is provided with a primary support 6, and the temporary hollow layer 4 is internally provided with core soil 3;

the blasting area 2 comprises a climbing channel 21 and a working platform 22; the core soil 3 is positioned on the operation platform 22, the climbing channel 21 is used for moving the cantilever tunneling machine to the operation platform 22, and the core soil 3 is excavated to form a free face;

the climbing passage 21 is provided with a plurality of cut holes 211, a plurality of peripheral holes 212 and a plurality of auxiliary holes 213, the peripheral holes 212 are arranged on the tunnel excavation contour line 5, the peripheral holes 212 are positioned at the outer sides of the auxiliary holes 213, and the auxiliary holes 213 are arranged at the outer sides of the cut holes 211;

the undercut hole 211, the peripheral hole 212, and the auxiliary hole 213 are blast holes.

The utility model discloses a subregion blasting mode gets rid of the soft layer in the construction tunnel through mechanical excavation to soft bottom, brings great disturbance when can avoiding the soft geological formation excavation of construction tunnel through mechanical excavation, carries out laying of big gun hole to the blasting area on hard geological formation again, greatly reduced the vibration influence that direct blasting brought, effectively controlled because of the deformation of the soft stratum in upper portion that the construction vibrations arouse and the influence to existing building.

In a specific embodiment, the cut holes 211 are symmetrically arranged on the climbing channel 21 to form a cut hole group, the cut hole group comprises four cut holes 211, four groups of the auxiliary holes 213 are symmetrically arranged on two sides of the cut hole group, each group of the auxiliary holes 213 comprises six auxiliary holes 213, every three auxiliary holes 213 are arranged in a group, and every two adjacent groups of the auxiliary holes 213 are arranged in parallel, two groups of the auxiliary holes 213 are arranged at the bottom end of the cut hole group, every three auxiliary holes 213 are arranged in a group in a collinear manner, and are arranged in parallel with the cut 2112, the peripheral holes 212 are arranged on the outer sides of the auxiliary holes 213, and the arrangement route of the peripheral holes 212 is arc-shaped.

In a specific embodiment, the initial supporting layer 6 is an arch structure, the initial supporting layer 6 comprises a profile steel frame, a reinforcing mesh and concrete, the reinforcing mesh is arranged on two sides of the profile steel frame, the concrete is filled between the profile steel frame, the reinforcing mesh and the inner wall of the construction tunnel 1, the concrete wraps the profile steel frame and the reinforcing mesh, and the profile steel frame is formed by welding longitudinal bars between steel arches.

In a specific embodiment, a plurality of advanced small guide pipes 7 are uniformly distributed in the soil mass layer on the outer side of the construction tunnel 1, and the advanced small guide pipes 7 are used for grouting into the soil mass layer on the outer side of the construction tunnel 1 before excavation, so that the surrounding rocks of the construction tunnel are prevented from deforming.

In a specific embodiment, the cut hole 211 is a wedge-shaped cut, the cut hole 211 includes a cut 2111 and a cut 2112, the cut hole 211 is located at one end of the cut 2111, the distance between two adjacent horizontally disposed cut holes 2112 is 800mm, the distance between two vertically disposed cut holes 2112 is 300mm, and the distance between one end of the horizontally disposed cut hole 2111 is 240mm.

In a specific embodiment, the bottom end of the construction tunnel 1 is provided with an inverted arch structure 7 and a bottom platform 8, the inverted arch structure 7 is arc-shaped, and a filling layer 71 is arranged between the inverted arch structure 7 and the bottom platform 8, and the filling layer is used for supporting and protecting the bottom platform 8 from being damaged.

In the embodiment, the construction tunnel further comprises a secondary lining 81, wherein the secondary lining 81 is arranged on the inner wall of the primary support layer 6 and is used for supporting and protecting the construction tunnel 1 and preventing the construction tunnel 1 from being deformed or collapsed due to external stress.

The specific process is as follows: step S1: and preparing for excavating for mechanical excavation, arranging a 10m climbing channel 21 and a 15m working platform 22, and constructing a lower step by adopting an intermediate slot.

Step S2: and (3) adopting mechanical construction for the upper pilot tunnel in the soft stratum, wherein the mechanical construction specifically comprises the steps of construction preparation, measurement and paying-off, face tunneling and face profile inspection (if the upper pilot tunnel is unqualified, equipment shifting, pneumatic pick chiseling, slag removal and slag tapping are carried out, and if the upper pilot tunnel is qualified, the equipment shifting, slag removal and slag tapping are carried out), and then setting a primary support 6 for entering the next cycle.

And step S3: the method comprises the steps of using an advanced small conduit 7 for grouting before excavation to prevent the surrounding rock of the construction tunnel from generating large deformation, reserving core soil 3 during excavation, adopting a cantilever type tunneling machine to perform subsection excavation on the tunnel within a step distance range in a cutting and grinding mode, when the surrounding rock of the periphery of the tunnel is excavated, firstly cutting and grinding a first excavation groove part 11 on one side wall of the tunnel along a contour line, then cutting and grinding a second excavation groove part 12 on the other side edge along the contour line, finally cutting and grinding a third excavation groove part 13 along the contour line of the edge of the vault of the tunnel to complete the whole excavation of excavation along the edge of the tunnel, performing primary support 6 after the excavation is finished, and then performing core soil 3 excavation to avoid the disturbance caused by the construction of the conventional drilling and blasting method.

And step S4: in the core soil 3 excavation link in the step S3, after the cantilever excavator is in place, a groove (the width of the excavator body) is horizontally cut from the bottom of the tunnel face, the excavator is moved forwards and is in place again, and after the cantilever excavator is in place, the cutting head performs left-right circular cutting from bottom to top. And loading the cut slag into a belt conveyor by the shovel part harrow claws during cutting, conveying the slag to the rear part of the development machine by the belt conveyor, and loading and conveying the slag to a temporary storage point of a vertical shaft by a loader. And after the arch part is excavated from the bottom, performing secondary trimming to accurately design the section. The cutting mode of the cantilever excavator is that the cutting is started from the bottom sweeping, and then the parts are cut step by step according to an S-shaped or Z-shaped left-right circular upward cutting route. And (3) selecting a right-handed cutting head to cut the hard rock, and gradually cutting the hard rock from left to right and from bottom to top or from right to left and from top to bottom.

Step S5: if rocks with different hardness are encountered in the step S4, different cutting teeth can be made, reasonable thread line arrangement of the cutting teeth is arranged, the machine is ensured to have better excavating capacity, the self-cleaning function is realized, the optimal cutting head can be selected according to actual working conditions, and the construction efficiency is improved. When the local part meets hard rock again, a small-diameter cutting head can be selected, the cutting force is large, the rock breaking capacity is strong, the tunneling difficulty and the cutting tooth consumption are reduced, and the width of rock shoulders on two sides is not less than 1m. After the mechanical excavation supporting is completed, the space between the excavation contour line and the tunnel face is not more than 70cm, the footage is advanced by 50cm every cycle, and the grid installation is carried out after the initial spraying is carried out on the excavation contour line when the surrounding rock of the construction tunnel is poor.

Step S6: after the mechanical excavation process is finished, a free face is formed, then blast holes in the blasting area 2 are arranged, blasting operation is carried out, and the problems of vibration speed and stratum disturbance caused by blasting are solved.

Step S7: the lower pilot tunnel that blasting area 2 was in hard stratum is the hard stratum of construction tunnel bottom, just hard stratum circumference hole 212 arranges along tunnel excavation contour line 5, and circumference hole 212 is apart from excavation limit 10cm to do benefit to the drilling, and the hole interval is E =600mm, and the relation between the dense coefficient of porthole K of circumference hole 212 and the line W of least resistance is K = E/W, and K =0.83, and smooth blasting effect is better this moment. The row spacing of the auxiliary eyes 213 is according to engineering experience b =700-1000mm, the hole spacing is according to engineering experience a =700-1000mm, and the peripheral eyes 212 are according to engineering experience a =650-750mm.

Step S8: as shown in fig. 4 to 5, through numerical simulation of a tunnel in a section Jiang Lu from xiangjiang road to jialing in Qingdao, the same model is used for simulating two different blasting modes of full-section blasting, upper-section mechanical excavation and lower-section blasting respectively, vibration speed monitoring points are arranged on the ground surface for monitoring the vibration speed of the ground surface after blasting, and the vibration speed monitoring points are compared with actual monitoring data on site, the vibration speed peak value under the full-section blasting condition in an analysis result is about 1cm/s, the vibration speed peak values of the upper-section mechanical excavation and the lower-section blasting are 0.5cm/s, and the data shows that the upper-section mechanical excavation is adopted, the lower-section blasting construction mode can reduce the influence of tunnel blasting operation on the vibration speed of the ground surface, and the effect is obvious.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims (7)

1. The combined blasting construction structure for mechanical excavation of the upper soft and lower hard stratum is characterized by comprising a construction tunnel (1) located in an earth-rock separation grounding layer, wherein an upper pilot tunnel of the construction tunnel (1) is provided with a blasting area (2) arranged by an adjacent hollow layer (4) and a lower pilot tunnel of the construction tunnel (1), the adjacent hollow layer (4) is located in an earth geological layer, and the blasting area (2) is located on the earth geological layer;

the temporary empty layer (4) is a hole body structure formed by sequentially excavating a first excavation groove part (11), a second excavation groove part (12) and a third excavation groove part (13) in the construction tunnel (1), the inner wall of the hole body structure is provided with a primary support (6), and core soil (3) is arranged in the temporary empty layer (4);

the blasting area (2) comprises a climbing channel (21) and an operation platform (22); the core soil (3) is positioned on the operation platform (22), and the climbing channel (21) is used for moving the cantilever tunneling machine to the operation platform (22) and excavating the core soil (3) to form a free face;

the climbing channel (21) is provided with a plurality of cut holes (211), a plurality of peripheral holes (212) and a plurality of auxiliary holes (213), the peripheral holes (212) are arranged on a tunnel excavation contour line (5), the peripheral holes (212) are positioned on the outer sides of the auxiliary holes (213), and the auxiliary holes (213) are arranged on the outer sides of the cut holes (211);

the undercut hole (211), the peripheral hole (212) and the auxiliary hole (213) are blast holes.

2. The combined blasting construction structure for mechanical excavation of the upper soft and lower hard formation, according to claim 1, is characterized in that the cut holes (211) are symmetrically arranged on the climbing channel (21) to form a cut hole group, two groups of auxiliary holes (213) are symmetrically arranged on two sides of the cut hole group, two groups of auxiliary holes (213) are arranged at the bottom end of the cut hole group, and the peripheral holes (212) are arranged on the outer sides of the auxiliary holes (213).

3. The combined blasting construction structure for mechanical excavation of the upper soft and lower hard formation is characterized in that the primary support (6) is an arch structure, the primary support (6) comprises a steel frame, reinforcing mesh sheets and concrete, the reinforcing mesh sheets are arranged on two sides of the steel frame, the concrete is filled between the steel frame, the reinforcing mesh sheets and the inner wall of the construction tunnel (1), the concrete wraps the steel frame and the reinforcing mesh sheets, and the steel frame is formed by welding longitudinal ribs between steel arches.

4. The combined blasting construction structure for mechanical excavation of the upper soft and lower hard formation is characterized in that a plurality of small advanced guide pipes (10) are uniformly distributed in the soil stratum outside the construction tunnel (1).

5. The combined blasting construction structure for mechanical excavation of the upper soft and lower hard formation is characterized in that the cut holes (211) are wedge-shaped, the cut holes (211) comprise a cut (2111) and a cut (2112), the cut holes (211) are located at one end of the cut (2111), the distance between two adjacent horizontally-arranged cut holes (2112) is 800mm, the distance between two adjacent vertically-arranged cut holes (2112) is 300mm, and the distance between one end of the adjacent horizontally-arranged cut hole (2111) is 240mm.

6. The combined blasting construction structure for mechanical excavation of the upper soft and lower hard formation is characterized in that an inverted arch structure (7) and a bottom platform (8) are arranged at the bottom end of the construction tunnel (1), the inverted arch structure (7) is arc-shaped, and a filling layer (71) is arranged between the inverted arch structure (7) and the bottom platform (8).

7. The combined blasting construction structure for mechanical excavation of upper soft and lower hard formations according to claim 3, characterized by further comprising a secondary lining (81), wherein the secondary lining (81) is arranged on the inner wall of the primary support (6).

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