CN118065912A - Hole distribution structure for blasting of water delivery tunnel and rapid construction method - Google Patents

Abstract

The invention discloses a blasting hole distribution structure for a water delivery tunnel and a rapid construction method, which comprises the following steps: s1: and (3) climbing section excavation supporting construction: the method comprises the steps of excavation construction, support construction, climbing section bottom excavation and climbing section second lining; s2: and (3) shield dismantling hole section excavation supporting construction: including excavation construction and support construction. The invention adopts four steps and nine steps to excavate, overcomes unsafe factors such as CD and CRD methods caused by the need of dismantling temporary supports and stress conversion, can adjust closing time in time, facilitates mechanized construction, facilitates construction process conversion, and overcomes the defects of heavy primary arch frame and difficult installation.

Description

Hole distribution structure for blasting of water delivery tunnel and rapid construction method

Technical Field

The invention relates to the technical field of tunnels, in particular to a blasting hole distribution structure for a water delivery tunnel and a rapid construction method.

Background

The tunnel is most often constructed by adopting a drilling and blasting method, and the drilling and blasting quality directly determines the safety and economical efficiency of tunnel construction. Because the construction environment of the water delivery tunnel is complex, on-site constructors often determine the angles, the depths and the quantity of drilling holes according to personal working experience and construction convenience, the quantity and arrangement of the drilling holes are not scientific, the input labor and the working hour quantity are increased, meanwhile, the blasting effect of the tunnel is easy to generate the phenomenon of super-undermining, the phenomenon of the tunnel is frequently generated, the integrity of surrounding rocks of the tunnel is reduced, the on-site construction danger coefficient is increased, the secondary lining workload is increased, and the cost is increased. Therefore, a water delivery tunnel blasting construction hole distribution method for improving tunnel excavation footage, excavation quality, construction safety and economic benefit is urgently needed.

In addition, for large-section tunnel construction, patent CN115929327a discloses a large-section tunnel construction method, which mainly comprises the following steps: dividing the section of the station into a left excavation unit, a middle excavation unit and a right excavation unit, wherein the left excavation unit is respectively provided with 1,3 and 5 guide pits from top to bottom, the right excavation unit is respectively provided with 2,4 and 6 guide pits from top to bottom, and the middle excavation unit is respectively provided with 7, 8 and 9 guide pits from top to bottom; step two, after the excavation and supporting of the guide holes at the 3 and 4 parts of the main body structure of the station are completed, a temporary transverse support is erected, one side of the guide hole is reserved with a connecting plate through a partition wall and is connected with the connecting plate through a high-strength bolt, and the other side of the guide hole is chiseled to spray concrete to expose a main body grid steel frame; thirdly, embedding the temporary cross braces into a grid steel frame, pouring concrete and the primary support of the main body into a whole, paving a reinforcing mesh, welding connecting ribs, welding the temporary cross braces and the connecting ribs, and finally pouring C15 concrete and finally forming the whole with the primary support of the station; fourthly, pulling an anchor rod above the temporary transverse brace Shi Zuodui, perforating the 1-part middle partition wall through the 7-part pilot tunnel to the 2-part pilot tunnel middle partition wall, putting in steel bars, threading two ends of the steel bars, grouting in the holes, welding brackets and steel frames on the 1-part middle partition wall and the 2-part pilot tunnel middle partition wall, welding a waist beam with the brackets by using the double-spliced steel, filling gaps between the waist beam and the primary support surface with wood wedges, and connecting the steel bars and the waist beam with high-strength bolts to bear force; and fifthly, after the construction is completed, continuously excavating guide holes on two sides to fall, excavating guide holes No. 7, dismantling the opposite-pull anchor rods, erecting temporary transverse struts, connecting by adopting connecting plates, and pouring concrete to form a whole with the temporary transverse struts on two sides. The method comprises the following steps: the construction design is complex, and the preparation time is long; the construction design is not suitable for weak surrounding rock and stratum of broken surrounding rock, and collapse and the like are easy to occur.

The patent CN109736844B discloses a quick construction method for tunnel primary support, which is characterized in that a concrete spraying arm (1) and two arch frame mounting arms (2) are arranged on an arch spraying trolley, a spraying device (3) is arranged at the front end of the concrete spraying arm (1), and the spraying device (3) is communicated with a pumping system (5); the front end of the arch centering installation arm (2) is provided with a grabbing mechanism (4); hanging baskets are arranged at the front ends of the concrete spraying arm (1) and the arch centering installation arm (2); it has the following problems: (1) Too much attention is paid to the research of tunnel supporting construction machinery and the innovation of supporting modes, the actual construction condition is not considered, and the cost is too high in actual application; (2) The mechanical construction steps are too complex and complicated, the requirement on the coordination degree among the working procedures is too high, and the difficulty in operation in actual construction is high.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a blasting hole distribution structure for a water delivery tunnel and a rapid construction method, which can effectively solve the problems in the prior art.

In order to achieve the above object, the present invention provides

A blasting hole distribution structure for a water delivery tunnel,

The tunnel section is divided into an upper step, a middle step and a lower step from top to bottom; the upper step is divided into at least three parts; the middle step and the lower step are respectively divided into at least two parts;

Each part of the upper step is provided with a cutting eye, an auxiliary eye, a bottom eye and a peripheral eye;

middle eyes, auxiliary eyes, bottom eyes and peripheral eyes are arranged on each part of the middle step and the lower step;

through setting up the position of undercut eye or middle eye, then arrange peripheral eye and bottom eye, finally arrange auxiliary eye according to the section size.

Further, the upper step is composed of a C-shaped section at the top and a D-shaped section at the bottom, the C-shaped section is divided into three parts, namely a ② part, a ① part and a ③ part from left to right, and the D-shaped section is divided into two parts, namely a ⑤ part and a ④ part;

The middle step is divided into two parts, namely ⑦ parts and ⑥ parts from left to right in sequence;

The lower step is divided into two parts, namely ⑨ parts and ⑧ parts from left to right.

Further, the undercut eye is arranged in the center of the excavation surface and is deviated downwards; the peripheral eyes are arranged on the profile line of the tunneling section and meet the requirements of smooth blasting, and the extrapolation slope of the peripheral eyes is 0.03-0.05.

Furthermore, the slitting holes adopt wedge slitting, the auxiliary holes adopt quincuncial uniform hole arrangement, and the peripheral holes are light explosion holes.

Further, the undercut eye and the auxiliary eye are both uncoupled continuous charges, and the peripheral eye is uncoupled spaced charges; and the small peripheral ocular explosive rolls are bound on the bamboo chips and are charged at intervals.

Further, the upper step adopts two-stage wedge-shaped slitting, and the depth of the slitting eye holes is 0.8m; auxiliary eye depth 0.5m, row spacing 0.7m; the peripheral holes are light explosion holes, the hole spacing is 0.45m, and the hole depth is 0.5m;

The middle-lower step is provided with the following holes: the row spacing is 0.8m, the auxiliary hole spacing is 0.7m, and the peripheral hole spacing is 0.45m.

The quick construction method for the water delivery tunnel comprises the following steps of:

S1: and (3) climbing section excavation supporting construction: the method comprises the steps of excavation construction, support construction, climbing section bottom excavation and climbing section second lining;

S2: and (3) shield dismantling hole section excavation supporting construction: including excavation construction and support construction.

Further, in the step of the climbing section excavation supporting construction,

The excavation construction includes:

(1) Excavating by adopting a full-section method;

(2) Adopting a hand drill to drill, explode and excavate, and designing contour line smooth surface blasting;

(3) Performing field treatment;

The support construction of digging includes:

Preparing construction, steel supporting, foot locking anchor rod construction, steel bar net hanging, connecting ribs, mortar anchor rod and advanced small guide pipe construction, concrete spraying to the design thickness, and next cyclic excavation supporting;

The climbing section bottom excavation comprises:

The non-excavated part at the bottom of the climbing section is synchronously excavated along with the excavation of the dismantling holes ⑥ part, the ⑦ part, the ⑧ part and the ⑨ part, steel arches with the same model as the upper arches are installed, steel bar meshes are paved and hung, longitudinal connecting ribs are welded, and each arch is divided into a system anchor rod and a foot locking anchor rod, and the system anchor rod and the foot locking anchor rod are sprayed and supported in time;

the climbing section II lining comprises:

and pouring the second lining of the transition section by adopting a transport hole second lining trolley, and backfilling light concrete in the cavity at the top.

Further, in the shield disassembly hole section excavation supporting construction, the excavation construction includes:

(1) Digging by four steps and nine steps, wherein the hole is in an anchor type;

(2) Adopting a hand drill to drill, explode and excavate, and designing contour line smooth surface blasting;

(3) And (5) field treatment.

Further, in the shield disassembly hole section excavation supporting construction, the supporting construction steps are as follows:

carrying out excavation and support on the ① th part, carrying out excavation and support on the ② th part after the excavation and support on the ① th part is completed by 5-10m, and carrying out the construction method as well as ① th parts; ③ When the part is excavated, firstly, the arch centering at the corresponding position of ① parts is firmly supported by DN89 steel pipes; ④ The temporary support between ①③ parts is lengthened to the bottom of ④ parts during part excavation, and a temporary transverse support is added to the bottom during part ④、⑤ excavation;

Wherein, excavation supporting is divided into four steps and nine steps to sequentially excavate ①-⑨ parts and support, and the excavation supporting interval between each two parts is 5-10 meters.

The invention has the advantages and beneficial effects that:

(1) The climbing section excavation support and the shield excavation support are provided with a set of complete system, and the steel arch, the reinforcing mesh, the anchor rods and the sprayed concrete are used as primary supports to be matched with advanced supports, so that a complete tunnel support system is formed, and surrounding rock deformation is effectively resisted.

(2) The invention adopts four steps and nine steps to excavate, thereby overcoming unsafe factors caused by the need of dismantling temporary supports and stress conversion, such as CD and CRD methods; the closing time can be adjusted in time, so that the mechanical construction is facilitated, and the construction procedure conversion is facilitated; overcomes the defects of heavy primary arch and difficult installation.

(3) The invention can find problems in time through the climbing section two lining, thereby ensuring construction safety and quality; the main stress is transmitted to the foundation by the vertical standard joint, so that the stress form is more stable; the assembly and disassembly are all carried out on the ground, so that the potential safety hazard of high-altitude disassembly is avoided.

(4) According to the invention, through the bottom excavation of the climbing section, the reserved holes are fewer in standard section positions of the upright posts, and the installation is more convenient; the installation is time-saving, labor-saving and material-saving; the influence of the support body and the template support on the construction progress of the main body structure is reduced, and the working efficiency is greatly improved.

(5) In the invention, the undercut hole can create good conditions for breaking down the rock of the working face and arranging other blastholes; the auxiliary eyes are used for expanding the groove cavities exploded by the slitting eyes and creating favorable conditions for blasting of the peripheral eyes; the peripheral eyes are used for controlling the forming contour of the tunnel section; the bottom hole is used for blasting and flattening the bottom of the tunnel.

(6) The invention sets auxiliary eyes and peripheral eyes around the cutting eyes, and then carries out blasting excavation. According to the tunnel construction method, the undercut hole is arranged as the free surface, so that inclined undercut can be replaced during blasting, meanwhile, the excavation footage of each cycle can be effectively increased during blasting, the excavation speed can be greatly improved, and the construction period is shortened.

Drawings

FIG. 1 is a schematic diagram of a blasting hole distribution structure for a water delivery tunnel according to the present invention;

FIG. 2 is a schematic diagram of a detonation network structure;

FIG. 3 is a schematic diagram of a charge configuration;

FIG. 4 is a schematic view of a first construction of an excavation supporting of a climbing section;

FIG. 5 is a second structural schematic diagram of a climbing section excavation support;

FIG. 6 is a schematic view of a third construction of an climbing section excavation support;

FIG. 7 is a fourth structural schematic diagram of a climbing section excavation supporting;

FIG. 8 is a schematic view of a shield disassembly hole section excavation structure;

FIG. 9 is a schematic view of a shield disassembly hole section support structure;

FIG. 10 is a diagram of a shield disassembly hole section excavation step;

FIG. 11 is an arch diagram of a shield disassembly hole segment.

Detailed Description

The following describes the embodiments of the present invention further with reference to the drawings and examples. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.

As shown in fig. 1, a blasting hole arrangement structure for a water delivery tunnel,

The tunnel section is divided into an upper step, a middle step and a lower step from top to bottom; the upper step is divided into at least three parts; the middle step and the lower step are respectively divided into at least two parts;

Each part of the upper step is provided with a cutting eye, an auxiliary eye, a bottom eye and a peripheral eye;

middle eyes, auxiliary eyes, bottom eyes and peripheral eyes are arranged on each part of the middle step and the lower step;

through setting up the position of undercut eye or middle eye, then arrange peripheral eye and bottom eye, finally arrange auxiliary eye according to the section size.

Cutting eyes: good conditions can be created for rock breaking down the working face and arranging other blastholes; the auxiliary eyes are used for expanding the groove cavities exploded by the slitting eyes and creating favorable conditions for blasting of the peripheral eyes; the peripheral eyes are used for controlling the forming contour of the tunnel section; the bottom hole is used for blasting and flattening the bottom of the tunnel.

As shown in fig. 10, the upper step is formed by a C-shaped section at the top and a D-shaped section at the bottom, wherein the C-shaped section is divided into three parts, namely ② parts, ① parts and ③ parts from left to right, and the D-shaped section is divided into two parts, namely ⑤ parts and ④ parts;

The middle step is divided into two parts, namely ⑦ parts and ⑥ parts from left to right in sequence;

The lower step is divided into two parts, namely ⑨ parts and ⑧ parts from left to right.

The cutting hole is arranged at the center of the excavation surface and is deviated downwards; the peripheral eyes are arranged on the profile line of the tunneling section and meet the requirements of smooth blasting, and the extrapolation slope of the peripheral eyes is 0.03-0.05. The hole opening of the bottom hole is about 15cm higher than the design level of the bottom plate, and the hole bottom is about 10cm-20cm below the level of the bottom plate so as to prevent underdigging, and the hole distance and the resistance line are the same as those of the auxiliary hole.

From the explosion shock wave rock breaking rule and the actual requirement of the engineering, during tunnel explosion, the slitting holes adopt wedge slitting, the auxiliary holes adopt quincuncial uniform hole distribution, and the peripheral holes are light explosion holes.

The upper step adopts a two-stage wedge-shaped undercut; auxiliary eye depth 0.5m, row spacing 0.7m; the peripheral holes are light explosion holes, the hole spacing is 0.45m, and the hole depth is 0.5m;

The middle-lower step is provided with the following holes: the row spacing is 0.8m, the auxiliary hole spacing is 0.7m, and the peripheral hole spacing is 0.45m.

In fig. 1 (in mm), the distribution of the undercut eye, the intermediate eye, the auxiliary eye, the bottom eye, and the peripheral eye in each section is shown in the following table:

① In the part, the slitting eyes are symmetrically arranged at the center of the excavation surface and are symmetrically arranged in pairs, the slitting eyes of the first group are in trisection and are arranged at the outer side of the slitting eyes of the first group, and the distance between the slitting eyes of the first group and the slitting eyes of the second group is 0.4m; the auxiliary eyes are provided with two groups, the first group of auxiliary eyes are arranged at the outer sides of the second group of undercut eyes, the second group of auxiliary eyes are arranged at the outer sides of the first group of auxiliary eyes, and the distance between the first group of auxiliary eyes and the second group of auxiliary eyes is 0.7 m; the peripheral eyes are arranged on the profile line of the tunneling section, the peripheral eyes are arranged outside the second auxiliary eyes, and the distance between the peripheral eyes and the second auxiliary eyes is 0.6 m; the bottom eye is arranged at the bottom of the ① part.

① Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Cutting hole	4	0.5	1	0.2	0.8	Phi 32 medicated roll
Cutting hole	6	0.8	3	0.2	1.2	Phi 32 medicated roll
							Auxiliary eye	12	0.5	5	0.15	1.8	Phi 32 medicated roll
Auxiliary eye	17	0.5	7	0.15	2.55	Phi 32 medicated roll
							Bottom eye	4	0.5	9	0.15	0.6	Phi 32 medicated roll
Peripheral eye	26	0.5	11	0.1	2.6	Phi 32 medicated roll
							Totals to	72				9.55

② In the section, the arrangement of the undercut eye, the auxiliary eye, the peripheral eye and the bottom eye is as shown in figure 1 and the following table,

② Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Cutting hole	4	0.8	1	0.2	0.8	Phi 32 medicated roll
Auxiliary eye	9	0.5	3	0.15	1.35	Phi 32 medicated roll
							Bottom eye	4	0.5	5	0.15	0.6	Phi 32 medicated roll
Peripheral eye	16	0.5	7	0.1	1.6	Phi 32 medicated roll
							Totals to	33				4.35

③ In the part, the arrangement of the undercut eye, the auxiliary eye, the peripheral eye and the bottom eye is shown in the figure 1 and the table below, wherein the arrangement mode of the undercut eye is similar to that of the ① part, and the peripheral eye is arranged on the profile line of the tunneling section; the bottom eye is arranged at the bottom of ② parts, and finally the auxiliary eyes are arranged according to the size of the section.

③ Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Cutting hole	4	0.5	1	0.2	0.8	Phi 32 medicated roll
Cutting hole	6	0.8	3	0.2	1.2	Phi 32 medicated roll
							Auxiliary eye	4	0.5	5	0.15	0.6	Phi 32 medicated roll
Auxiliary eye	13	0.5	7	0.15	1.95	Phi 32 medicated roll
							Bottom eye	4	0.5	9	0.15	0.6	Phi 32 medicated roll
Peripheral eye	23	0.5	11	0.1	2.3	Phi 32 medicated roll
							Totals to	54				7.45

④-⑨ In the part, a plurality of middle eyes are transversely arranged to form groups, a plurality of middle eye groups are longitudinally and parallelly arranged in each part, and peripheral eyes are arranged on the contour line of the tunneling section; the bottom eyes are arranged at the bottoms of the parts, and finally the auxiliary eyes are arranged according to the size of the section.

④ Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Middle eye	5	0.5	1	0.15	0.75	Phi 32 medicated roll
Middle eye	6	0.5	3	0.15	0.9	Phi 32 medicated roll
							Middle eye	5	0.5	5	0.15	0.75	Phi 32 medicated roll
Middle eye	6	0.5	7	0.15	0.9	Phi 32 medicated roll
							Bottom eye	7	0.5	9	0.15	1.05	Phi 32 medicated roll
Auxiliary eye	11	0.5	11	0.15	1.65	Phi 32 medicated roll
							Peripheral eye	9	0.5	13	0.1	0.9	Phi 32 medicated roll
Totals to	49				6.9

⑤ Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Middle eye	10	0.5	1	0.15	1.5	Phi 32 medicated roll
Middle eye	11	0.5	3	0.15	1.65	Phi 32 medicated roll
							Middle eye	10	0.5	5	0.15	1.5	Phi 32 medicated roll
Middle eye	11	0.5	7	0.15	1.65	Phi 32 medicated roll
							Bottom eye	13	0.5	9	0.15	1.95	Phi 32 medicated roll
Auxiliary eye	5	0.5	11	0.15	0.75	Phi 32 medicated roll
							Peripheral eye	9	0.5	13	0.1	0.9	Phi 32 medicated roll
Totals to	69				9.9

⑥ Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Middle eye	6	1.0	1	0.3	1.8	Phi 32 medicated roll
Middle eye	6	1.0	3	0.3	1.8	Phi 32 medicated roll
							Middle eye	6	1.0	5	0.3	1.8	Phi 32 medicated roll
Middle eye	6	1.0	7	0.3	1.8	Phi 32 medicated roll
							Bottom eye	9	1.0	9	0.3	2.7	Phi 32 medicated roll
Auxiliary eye	6	1.0	11	0.3	1.8	Phi 32 medicated roll
							Peripheral eye	8	1.0	13	0.2	1.6	Phi 32 medicated roll
Totals to	47				13.3

⑦ Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Middle eye	6	1.0	1	0.3	1.8	Phi 32 medicated roll
Middle eye	6	1.0	3	0.3	1.8	Phi 32 medicated roll
							Middle eye	6	1.0	5	0.3	1.8	Phi 32 medicated roll
Middle eye	6	1.0	7	0.3	1.8	Phi 32 medicated roll
							Bottom eye	9	1.0	9	0.3	2.7	Phi 32 medicated roll
Auxiliary eye	12	1.0	11	0.3	3.6	Phi 32 medicated roll
							Peripheral eye	8	1.0	13	0.2	1.6	Phi 32 medicated roll
Totals to	53				15.1

⑧ Part blasting parameter table

Gun hole name	Number of blastholes	Depth m of blast hole	Segment bit	Single hole dosage kg	Single stage dosage kg	Remarks
							Middle eye	6	1.0	1	0.3	1.8	Phi 32 medicated roll
Middle eye	6	1.0	3	0.3	1.8	Phi 32 medicated roll
							Middle eye	6	1.0	5	0.3	1.8	Phi 32 medicated roll
Middle eye	6	1.0	7	0.3	1.8	Phi 32 medicated roll
							Auxiliary eye	6	1.0	9	0.3	1.8	Phi 32 medicated roll
Bottom eye	12	1.0	11	0.3	3.6	Phi 32 medicated roll
							Peripheral eye	15	1.0	13	0.2	3.0	Phi 32 medicated roll
Totals to	57				15.6

⑨ Part blasting parameter table

As shown in fig. 2, the detonation network structure comprises an in-hole detonator, a booster detonator, a detonation detonator and a detonation needle, wherein the in-hole detonator is connected with the detonation detonator through the booster detonator, and the detonation detonator is connected with the detonation needle;

In order to ensure accurate and reliable initiation, a plastic detonating tube and detonator duplex network is adopted, namely 2 detonators are arranged at each detonator, and the detonating tube is not knotted and is not thinned during connection; the number of detonators in each cluster connected to each blasting cap is equal to or less than 20. The black adhesive tape for the detonating detonator is wrapped. After the network connection is completed, the special person can check and accept the network connection, and the detonation can be performed after the network connection is correct.

As shown in fig. 3, both the undercut eye and the auxiliary eye employ uncoupled continuous charges and the peripheral eye employ uncoupled spaced charges; and the small peripheral ocular explosive rolls are bound on the bamboo chips and are charged at intervals. Blocking the blast holes can improve the utilization rate of the explosive energy, thereby reducing the explosive consumption and reducing the blasting vibration effect. All the charging blastholes are blocked by stemming, so that the blocking quality is ensured. The part of the cut hole which is not filled with the explosive is fully blocked, and the blocking length of the other tunneling holes is more than 80% of the resistance wire. Stemming is made using 2/3 sand and 1/3 loess and cement.

The quick construction method for the water delivery tunnel comprises the following steps of:

S1: and (3) climbing section excavation supporting construction: the method comprises the steps of excavation construction, support construction, climbing section bottom excavation and climbing section second lining;

S2: and (3) shield dismantling hole section excavation supporting construction: including excavation construction and support construction.

1. The step S1 of climbing section excavation supporting construction comprises the following steps:

(1) Excavation construction, as shown in FIG. 4

① The full-section method is adopted for excavation, the size of the section of the excavation is 7.8m multiplied by 7.5m, the hole type is a gate hole type, the excavation slope ratio is 1:3.125, namely each arch frame is Cheng Shenggao 0.259.259 m higher.

② The contour line smooth blasting is designed by adopting the hand drill drilling blasting excavation. The class of the surrounding rock of the stratum where the grotto is located is class IV surrounding rock, each cycle of excavation is 0.8-1.0 m, and the concrete footage is reasonably arranged according to the surrounding rock on site.

③ And (3) performing field treatment, namely performing safety treatment on the backhoe after blasting of each row of cannons, and transporting the excavated slag to a specified slag field by adopting a 2.0m ³ side dump loader to load a 20t dump truck.

(2) Support construction

The supporting construction procedure is as follows: construction preparation, steel support, foot locking anchor rod construction, steel bar net hanging, connecting ribs, mortar anchor rod construction, advanced small guide pipe construction, concrete spraying construction to the design thickness, and next cyclic excavation supporting. The method comprises the following steps:

① The surrounding rock type is IV, the steel arch is HW 150.150 section steel arch, each arch is assembled according to 5 sections, the arch spacing is 0.8M, the arch is connected by adopting M22. 80,8.8 high-strength bolts, 16 arch covers are combined, welding is carried out at the arch connection part, and the welding seam is firmly connected by full bolts.

② The verticality deviation of the steel arch is not more than +/-2 degrees, and the interval deviation is not more than +/-5 cm; the height of the arch frame is strictly controlled, and the deviation is not more than +/-5 cm.

③ The arch centering is located on the complete rock, if surrounding rock is broken, the arch springing virtual slag group is completely filled, and then the arch springing virtual slag group is backfilled with sprayed concrete; the arch centering is clung to the rock surface as much as possible, if the block is dropped, the sprayed concrete is used for backfilling and compacting, and a forbidden hole is formed;

④ The steel bar meshes are welded into a net shape by adopting light round steel bars with phi 8mm, when IV-class surrounding rock supports are formed, the mesh size is 200 multiplied by 200mm steel bar net shape, the width of the meshes is prefabricated according to the arranging condition of the steel arch frame according to the design requirement, and the processed mesh size meets the design requirement. The size of the net sheet is determined by the distance between arches and the convenient operation. Each reinforcing mesh is fastened by anchor rods, so that the mesh is clung to the wall of the hole, the adjacent reinforcing meshes are lapped, the longitudinal and transverse reinforcing meshes are corresponding during lapping, and the lapping length is not less than 200mm.

⑤ After the steel arch is erected, each segment end is locked by adopting a foot locking anchor rod (C22, L=2.5m, and the downward inclination is set at 15 degrees), and the injection strength grade is not lower than 20Mpa cement mortar. And the end parts of 2 anchor rods at each point are bent for 10cm and welded on the left side and the right side of the steel arch frame respectively, the end parts of the anchor rods are welded with the arch frame, and if the positions of the lock foot anchor rods and the system anchor rods are identical, the lock foot anchor rods can replace the system anchor rods.

⑥ The system anchor rod adopts a full-length bonding type cement mortar anchor rod. The C22 steel bar is processed into 3m according to the design requirement, the end head is polished, the tail of the anchor rod is sleeved by a threading machine, the length of the thread is 10cm, and the backing plate is 15cm x 8mm (length x width x thickness). The distance between the anchor rods is 0.8m, the anchor rods are arranged in a quincuncial shape, and the hole site deviation is not more than 100mm. The anchor rod hole is drilled by an air gun, the depth of the hole meets the design requirement, the ultra-depth is not more than 10cm, and the diameter of the anchor rod hole is more than 20 mm. Grouting: cement mortar mixing ratio: water: cement=1:1 to 1:2. The strength grade of the mortar is not lower than 20MPa. The cement mortar should be prepared at any time. And a supporting plate at the tail end of the anchor rod is arranged, and the supporting plate is tightly clung to the rock surface. The weight is not required to be knocked and hung at will just after the anchor rod is installed.

⑦ The connecting ribs are C22 steel bars, are welded on the inner side of the arch frame, are adjusted according to the arch frame spacing during blanking and are 2-3 cm shorter than the arch frame spacing, and are required to be welded firmly.

⑧ The arch crown is reinforced by grouting with phi 42 leading small guide pipes, the length of the guide pipes is 3.0m, the circumferential spacing is 0.3 m, and the longitudinal lap joint length is 1.0 m. The small guide pipe is a hot rolled seamless steel pipe with phi 42mm, the wall thickness is 3.5mm, the front end is made into a sharp cone shape, the tail part is welded with reinforcing hoops with phi 8mm, the pipe wall is drilled with holes with plum blossom shape at intervals of 10-20 cm, the diameter of the holes is 6-8 mm, and the tail part length is not less than 30cm and is used as a slurry stop section without drilling.

(3) Climbing section bottom excavation

As shown in fig. 5, the non-excavated part at the bottom of the climbing section is excavated synchronously along with the excavation of the dismantling holes ⑥、⑦ and ⑧、⑨, and HW150 x 150 section steel arches with the same model as the upper arches are installed. The steel bar meshes are paved and hung, the longitudinal connecting ribs are welded, a system anchor rod and a foot locking anchor rod are arranged on each arch frame in a split mode, and the support is sprayed and mixed in time.

(4) Climbing section two lining

As shown in fig. 6 and 7, the 20m transition section secondary lining is still poured by adopting a transport hole secondary lining trolley, and the light concrete is backfilled in the top cavity.

2. S2, shield disassembly hole section excavation supporting construction comprises the following steps:

(1) Excavation construction

① As shown in fig. 8, the excavation is performed in four steps and nine steps, the hole type is an anchor type, and the excavation section size is 14.5m x 15.949m. And after the shield is taken into the shield disassembly hole section, the road surface of the climbing section is firstly trimmed, and a temporary ramp is trimmed, so that the convenience in upper excavation of the disassembly hole and the transportation requirement are ensured. Carrying out ① parts of excavation and erecting temporary supporting arches on two sides, spraying, mixing and sealing. And carrying out ②-⑨ part four-step excavation in sequence after normal tunneling of ① parts of sections.

② The contour line smooth blasting is designed by adopting the hand drill drilling blasting excavation. The class of the surrounding rock of the stratum where the cavity is located is IV class surrounding rock, the section is large, the single-cycle footage of ①～⑤ parts is 0.5m, and the single-cycle footage of ⑥～⑨ parts is 1.0m. And mechanical excavation is adopted when surrounding rock is poor.

③ And carrying out safety treatment on the backhoe after blasting of each row of cannons, and transporting the excavated slag to a specified slag field by adopting a 2.0m ³ -t side dump truck to load into a 20-t dump truck.

(2) Support construction

As shown in fig. 9, the shield disassembly hole section support adopts HW150×150 full ring steel arches, and each frame is assembled according to 17 segments. The arch centering is arranged at a distance of 0.5m, and double-layer phi 8 reinforcing steel meshes are hung. C22 connecting ribs are longitudinally arranged between the arches, and the circumferential spacing of the connecting ribs is 1 m. The arch part is provided with phi 42 advanced grouting small guide pipes, the length is 3m, the circumferential spacing is 0.3m, and the longitudinal spacing is 1.0m. When surrounding rock is broken or water outlet conditions influence excavation stability, grouting pre-reinforcement is carried out on the face and the vault surrounding rock. The system anchor rods are C25 mortar anchor rods, and the spacing between the anchor rods is 0.8m. Arch mortar anchor rods (0.8 m exposed) are installed at intervals of l=6.8m and l=4.8m, and are arranged in a quincuncial manner. Side wall mortar anchor rods (0.5 m exposed) are installed at intervals of L=6.5m and L=4.5m, and are arranged in a quincuncial manner. Each arch frame is provided with 1 group of C22 foot locking anchor rods at two ends, the length of the foot locking anchor rods is 3m, the angle of the foot locking anchor rods is 30 degrees, and the foot locking anchor rods are firmly welded with the arch frames. Spraying C30 polyvinyl alcohol fiber concrete, and the thickness is 25cm.

The support steps are as follows:

As shown in fig. 10-11, a double-layer reinforcing mesh of Φ8@150×150 is hung after the ① part is excavated, the HW150×150 steel arches are installed, and two side temporary arches are installed. The arch frames are connected with the whole body through longitudinal connecting steel bars, foot locking anchor rods are immediately arranged after the arch frames are installed (the foot locking anchor rods are arranged in a pressing drawing, each line segment in the drawing represents 1 group of foot locking anchor rods), the system anchor rods and the arch parts are grouting in advance into small guide pipes, and grouting operation is carried out after inspection and acceptance by a supervision engineer. In order to ensure construction safety, ② part excavation and support are carried out after ① part excavation and support is completed for 5-10m, and the construction method is the same as ① part. ③ When the part is excavated, the arch centering at the corresponding position of ① parts is firmly supported by DN89 steel pipes. ④ And when the part is excavated, the part ①③ is temporarily supported and lengthened to the bottom of the part ④, and when the part ④、⑤ is excavated, a temporary transverse support is added to the bottom. Carrying out ①-⑨ parts of support and excavating support at 5-10m intervals among the parts. The excavation process adopts the principle of 'short footage, weak blasting, strong support and duty measurement', and the anchor rod and the advanced small guide pipe are timely grouting.

3. The specific process flow of the excavation process in the step S1 and the step S2 is as follows:

(1) Excavation preparation

Wind, water and electricity in the hole are ready, and constructors and machines are ready to be in place.

(2) Measuring pay-off

The measurement of the wire control network in the hole is carried out by adopting a total station level. The construction measurement is generally carried out by adopting a total station, and the rock anchor beam is lofted by adopting an infrared laser positioning technology. The measuring operation is implemented by professionals, the central line of the cavity and the design rule line are measured and placed after each row of cannons, and hole positions are distributed according to blasting design parameters. The measurement of the excavation section is carried out before the concrete is sprayed, and the measurement interval is 3m. And (5) carrying out comprehensive inspection and retest of the hole axis at regular intervals, and ensuring the quality of a measurement control procedure. Meanwhile, along with the excavation and support progress of the grotto, a pile mark is arranged on the wall and the top of the grotto at intervals of 20 m. The measurement control points in the holes are buried firmly and hidden, so that the protection is good, and the damage of mechanical equipment is prevented.

(3) Drilling operation

And (5) drilling by qualified drillers strictly according to the measured center line, waist line, excavation contour line and measurement hole distribution. Each driller partition and each part is fixed with a person to position the driller, and strict driller operation quality economic responsibility system is implemented. The technical staff is convenient to find and solve the technical problems in the field in time by the side station in the field. Each row of cannons is checked by an on-duty engineer according to the requirements of 'flatness, straightness and alignment', so that the hole bottoms of the cannon holes fall on the same vertical section specified by blasting (bench blasting is a horizontal plane); to reduce overexcavation, the outer deflection angle of the peripheral holes is controlled at the minimum angle that can be achieved by the device. The deviation of the photo-explosion hole, the pre-cracking hole and the cut hole is not more than 5cm, and the deviation of other blast hole positions is not more than 10cm.

(4) Charging, connecting wire and detonating

Before charging, high-pressure air is used for sweeping the hole, and charging and blasting can be carried out after the blast hole is checked to be qualified; the charging, blocking and detonating circuit connection of the blast hole are implemented by powderman which is qualified according to the approved drilling and blasting design, and the charging strictly complies with the blasting safety operation rules.

The cut hole is charged by a skilled powderman, the light explosion hole and the pre-cracking hole are bound on the bamboo chips by small explosive rolls for spaced charging. The drilling frame trolley is used as ascending equipment for charging, the charging of the cut hole, the expansion hole and other blastholes is compact, the blocking is good, the charging is strictly carried out according to a blasting design diagram (the blasting parameter implementation process is continuously adjusted and optimized), the magneto-electric detonator is used for connecting a detonation network, and finally powderman and an on-duty technician check to confirm that no errors exist, evacuation personnel and equipment are responsible for detonation, and powderman.

(5) Ventilating and fume-dispersing and dust-removing device

Ventilation equipment is always started to ventilate in the excavation construction process of each grotto, and the ventilation system is utilized to discharge smoke and remove dust, so that the concentration of harmful gas is ensured to be reduced to be within an allowable range within a specified time after blasting. And after blasting smoke scattering is finished, sprinkling water to the blasting slag pile on the excavated surface for dust removal.

(6) Security treatment

The whole process of construction is stared and controlled by a full-time security officer. After blasting, the residual dangerous stones and fragments on the face and the side roof arch are removed by a digger, the safety of entering personnel and equipment is ensured, and after safety treatment is carried out on the broken hole section of the rock face, a layer of concrete with the thickness of 5cm can be sprayed. And after the stand is in place, the worker is guided by a working staff to conduct manual evacuation before the stand is in place, and the constructor stands on the supported safety section to conduct comprehensive manual evacuation by using steel bars or anchor rods. And (5) mechanically clearing the risk again after the spraying is finished, and performing next-cycle construction after checking and confirming by teammates and full-time safety officers. In the construction process, the surrounding rock stability of the excavated hole section is frequently checked, and loose rock blocks which possibly collapse are pried.

(7) Slag discharging and bottom cleaning

And carrying out safety treatment on the backhoe after blasting of each row of cannons, and transporting the excavated slag to a specified slag field by adopting a 2.0m3 side dump loader to load a 20t dump truck. After the slag discharge is finished, the dredging machine is used for deep evacuation, and the side station of the team leader on duty is used for commanding during evacuation, so that complete evacuation is ensured, and preparation is made for the next cyclic drilling and blasting operation.

(8) Surrounding rock support

After each row of cannons is excavated, carrying out random anchor spraying support and system support on local rock mass with poor stability in time, wherein the anchor rods, the hanging net and the sprayed concrete of the regional system with good surrounding rock can lag the excavation operation construction, and before the primary support, the working procedures of standing frames, anchor rod support and the like are carried out after the complete evacuation is ensured by manual work.

4. The support construction process in the steps S1 and S2 comprises mortar anchor rod construction, net hanging and concrete spraying construction, steel support construction and advanced grouting small conduit construction. The specific flow is as follows:

(1) Construction process of mortar slurry anchor rod

Before the anchor rod construction, the field test of the anchor rod is carried out, and the following anchor rod test work is mainly carried out:

① And screening 2-3 groups of mortar mixing ratios meeting design requirements through an indoor test, and compiling test outline batches to carry out a productivity test.

② Grouting compactness test: the anchor rod and plastic pipe (or steel pipe) with the same diameter and length, anchor hole aperture and inclination as those of the on-site anchor rod are selected, cement slurry or cement mortar mixed with the same materials and proportions as those of on-site grouting is adopted, grouting is carried out according to the same grouting technology of on-site construction, and after curing for 7 days, the pipe is cut open to check the compactness. The anchors of different types and different lengths are tested. The test plan reports the approval of the supervisor, and the test is carried out according to the approved plan, and the supervisor stands by the station in the test process. And (3) the grouting compactness of the test section is not less than 90%, otherwise, the test process is further perfected, and then the test is carried out until the grouting compactness of 90% or more is achieved. The actual construction is strictly carried out according to the grouting process approved by the supervisor.

After the anchor rod field test is completed, the normal construction of the anchor rod can be performed, and the main working procedures are as follows:

① Pore-forming

A. the bore diameter of the common mortar anchor rod is larger than the diameter of the anchor rod, and the bore diameter is larger than the diameter of the anchor rod by more than 20 mm. a. The drill bit is selected to meet the requirement, the drilling points are provided with obvious marks, and the deviation of the position of the hole in any direction is smaller than 100mm. The rock anchor beam position anchor rod requires that the deviation of the upper and lower hole positions is not more than +/-30 mm, and the deviation of the left and right hole positions is not more than +/-100 mm.

B. The hole axis direction of the anchor rod hole meets the requirement of a construction drawing, and the hole axis direction of the anchor rod of the system is perpendicular to the excavation surface; the direction of the hole axis of the locally random reinforced anchor rod is opposite to the direction of a possible sliding surface, the intersection angle of the hole axis and the sliding surface is larger than 45 degrees, and the deviation of the drilling orientation is not larger than 5 degrees. The depth of the anchor hole must meet the design requirement, and the deviation value of the hole depth is not more than 50mm.

C. after the drilling is finished, spot check is carried out on the drilling specification (aperture, depth and gradient) of the anchor rod hole, and record is made, and the unqualified anchor rod is required to be set in a supplementary mode.

D. After drilling, the loose rock particles and accumulated water in the holes are cleaned by wind and water; if immediate insertion of the bolt is not required, the ports should be blocked for proper protection and the borehole should be inspected to determine if re-cleaning is required prior to installation of the bolt.

② Anchor rod installation and grouting

A. inserting the rod immediately after grouting in the drill hole; the inserting direction of the anchor rod is consistent with the hole direction, and the anchor rod is properly rotated (manually twisted or twisted by a pipe wrench) in the inserting process;

b. the anchor rod is slowly inserted and conveyed, and the anchor rod is rotated and then inserted when the anchor rod has a spring feel, so that knocking and inserting are avoided as much as possible.

③ Checking and accepting

The mortar anchor rod is detected by adopting a tensile plate test.

And after the construction of the mortar anchor rod is completed, the mortar anchor rod reaches the design age, the on-site supervision random sampling inspection is used for carrying out drawing test detection, and the tensile drawing value meets the design requirement.

(2) Screen spraying concrete construction

The concrete sprayed in the hole is mainly C30 concrete sprayed in the hole. In the construction process, the steel bar net is sprayed for 3 cm-5 cm in thickness, then the steel bar net is paved and hung, the steel bar net is firmly connected with the anchor rod and the additional dowel bars (or expansion bolts), and finally the steel bar net is sprayed for 2 to 4 times to reach the designed spraying thickness. The net hanging is manually carried out by a platform truck. The sprayed concrete is transported to a working surface by a stirring transport vehicle, and is sprayed by a concrete sprayer.

The main hole concrete spraying is carried out by adopting a wet spraying method, the spraying concrete and the excavation, the anchor rod construction follow-up parallel cross operation, and the construction is carried out according to the following technological process:

① In situ test

By combining the past construction experience, the production process parameters and the mixing ratio of the sprayed concrete which not only meet the construction requirement but also meet the design requirement can be optimized and selected through an indoor test. The method comprises the following steps:

A. Screening 2-3 combination ratios through an indoor test, and compiling a test outline report for a productivity test;

B. Selecting a site (or supervision designation), and selecting 6-9 representative sites according to the category and the site of the surrounding rock to carry out a productivity test;

C. According to the outline requirements of design and test, adopting the screened mix proportion to respectively carry out injection operation, setting the injection range to be 10m ² (or one unit volume), setting enough wood forms or bottomless steel forms (for detecting compression resistance, tensile resistance, impermeability, bonding strength with the rock surface and the like) on the injected rock surface according to the standard requirement, simultaneously respectively sampling according to the test standard to prepare standard test blocks, and curing according to the same condition;

D. comparing the physical characteristics of the test piece meeting the design requirements (including blasting influence degree);

E. and (3) sorting, analyzing and testing records, selecting proper blending proportion and construction process parameters according to factors such as comprehensive resilience, strength guarantee rate, construction work efficiency and the like, and reporting and delivering to a design supervision unit for approval.

② Preparation work

The thick control mark is buried, the operation area has enough ventilation illumination, and all mechanical equipment and pipelines are checked before spraying, so that the normal construction is ensured. The treatment measures are carried out on the seepage surface, the treatment materials are prepared, and the preparation of sampling of the warehouse surface is connected.

③ Mixing and transporting

The mixing ingredients are strictly mixed according to the mixing proportion determined by the test, the stirring time is enough, the transportation and storage of the mixing ingredients are rainproof and pollution-proof, the mixing ingredients are strictly sieved before being put into a machine, and the transportation and storage time of the mixing ingredients meet the related technical indexes. The steel fiber concrete is evenly mixed and stirred. The sprayed concrete is transported to the working surface by a stirring transport vehicle.

And (3) cement: the ordinary silicate cement is preferably selected, and when the special requirement is met, special cement can be adopted after approval by a supervisor. The cement strength grade should not be below p.o.42.5. The incoming cement should be a quality certificate of the manufacturer.

Aggregate: the fine aggregate adopts hard and durable coarse sand and medium sand, the fineness modulus is preferably more than 2.5, and the water content is preferably controlled to be 5-7% when in use; the coarse aggregate adopts durable pebbles or broken stones, and the grain size is not more than 15mm; aggregate containing activated silica must not be used in shotcrete.

Water: all drinking water meeting the national standard can be used for mixing and maintenance. Untreated industrial sewage and domestic sewage cannot be used for mixing and curing concrete. When surface water, underground water and other types of water are used for mixing and curing concrete for the first time, the water can be used after being inspected to be qualified according to the existing related standards.

Additive: the quality of the accelerator meets the requirements of construction drawings and has the quality certificate of a production plant, the initial setting time is not more than 5min, the final setting time is not more than 10min, and the selected additive is approved by a supervisor.

Reinforcing bar (wire) mesh: a smooth reinforcing steel bar net with the yield strength not lower than 235MPa is adopted.

And (3) external doping: when the engineering needs to adopt the external admixture, the admixture amount should be determined through experiments, and the performance of the sprayed concrete after the external admixture is added must meet the design requirement.

The sprayed concrete is used according to the construction drawing or the range indicated by the supervisor, the concrete mixing amount is determined through experiments when the concrete mixing amount is implemented, and the supervisor approves the concrete mixing amount.

④ Rock awash noodles

Removing pumice on the excavated surface, stone slag on the basement and deposits; the smooth excavation surface is treated; installing a working platform; flushing the sprayed surface by a high-pressure air gun; a mark for controlling the thickness of the sprayed concrete is buried.

⑤ Reinforcing mesh

According to the requirements of construction drawings, a reinforcing steel bar net is arranged before concrete spraying, the distance between the reinforcing steel bar nets is 150mm, and the reinforcing steel bars adopt smooth round reinforcing steel bars with the diameter of 8 mm.

⑥ Jet point

The concrete spraying operation is carried out in a segmented and segmented way, the spraying sequence is from bottom to top, and the condition that the rebound material covers the non-sprayed surface is avoided. And during layered spraying, the later layer is performed after the concrete of the former layer is finally solidified, and if the concrete is sprayed after the final solidification is performed for 1h, the spraying surface is washed by high-pressure air water.

The injection operation strictly performs the operation procedure of the injector: feeding the injector continuously; maintaining the working air pressure of the sprayer stable; when the spraying operation is finished or interrupted due to reasons, the accumulated materials in the spraying machine and the conveying pipe should be cleaned, so that the pipeline is prevented from being blocked.

In order to reduce the rebound quantity and improve the injection quality, the spray head should maintain a good working state. And (3) adjusting the wind pressure, keeping the spray head perpendicular to the sprayed surface, controlling the spray distance within the range of 0.6-1.2 m, and adopting a correct spiral track spray construction process. And (3) performing thick spraying inspection (through buried points) on the part just sprayed, and performing re-spraying treatment in time. Spraying the net hanging part until no obvious net strips exist.

⑦ Maintenance and detection

After the sprayed concrete is finally set for 2 hours, water spraying maintenance is needed, the maintenance time is generally not less than 14 days, and when the air temperature is lower than 5 ℃, the water spraying maintenance is not needed. When the air humidity around the sprayed concrete reaches or exceeds 85%, the concrete can be naturally cured.

And coring detection in time, summarizing detection reports on schedule, and carrying out quality assessment and engineering quality acceptance in time. And taking a core sample with the diameter of 100mm from a designated position as a tensile test according to the requirements of a supervisor, and reporting test result data to the supervisor. All the drill core sampling parts should be backfilled with dry and hard cement mortar.

(3) Steel support construction

The upstream shield dismantling hole arch frame is designed to be HW150 x 150, the truss distance is 0.5m, each steel support section is manufactured by machining, connecting steel plates are arranged at two ends of each section of steel frame, the steel frames are connected through bolts, and three sides of the connecting steel plates are welded firmly; the steel support is erected after measuring the section and closely clings to surrounding rocks, a gap is wedged by a steel wedge, and feet on two sides are arranged on a firm foundation; and the transverse connection is realized by C22@100cm, so that the integrity of the steel support is improved.

After the steel arch is erected, locking leg locking anchor rods (C22 mortar anchor rods, L=3m) are adopted, and after the end parts of 2 anchor rods at each point are bent for 10cm, the end parts are respectively welded on the left side and the right side of the steel arch.

The steel support construction process flow is as follows:

① Setting out and moulding of steel frame

And manufacturing dies with different specifications according to different section steel manufacturing radiuses. The manufacturing precision of the steel frame is controlled by the mould, so the requirement on the manufacturing precision of the mould is higher, and the main technical indexes of the mould manufacturing control mainly comprise inner and outer arc lengths, chord lengths and radiuses.

The mould is manufactured by adopting a field lofting method, a mould mass sample is firstly lofted, then a section steel bending machine is used for bending the section steel, and the section steel is subjected to multiple proofreading until the length, the chord length and the radius of the inner arc and the outer arc of the section steel completely meet the design requirements, and the position of the joint plate is accurately found out.

② Bending and cutting steel frames

The length of the section steel is fixed to 12m, the section steel is bent and machined, and the elongation of the hydraulic cylinder is properly adjusted according to the machining radius. In the bending process of the section steel, an experienced worker is required to operate the motor to conduct unified command. The section steel passes through the mould after passing through the bending machine, and is subjected to radian inspection by referring to the mould, if the radian does not meet the requirement, the section steel is bent again, and after being bent, the section steel is temporarily stored on the same 4 self-made simple steel bar stool (with a roller).

When a unit is bent to cut, the method of measuring the outer arc length, measuring the inner chord length and the like can be adopted for the section steel cutting, a sizing caliper is utilized to control the section steel cutting surface to be in the radial direction, then a vector stroke line is utilized, the oxygen welding cutting is utilized, the cutting gun is required to be perpendicular to the section steel during the cutting, the cutting surface is ensured to be smooth, and after the cutting is finished, the protruding edges and corners of the cutting surface are polished.

And suspending bending before the bending of the single 12m section steel is finished, firmly welding the next 12m section steel with the section steel, and then continuing to bend. And the rest section steel in the working process is lifted to a storage place for placement, and the section steel bending machine is cleaned.

③ Welding of connecting plates

Cutting the bent section steel, checking the arc length of the section steel, and if the section steel is short, welding a connecting plate and lengthening the section steel; if the section steel is longer, the secondary cutting is needed. After the radian and the length of the section steel meet the design requirements, the connecting plate is placed in the clamping groove, the section steel with small deviation from the radial direction of the cutting line is adjusted through the connecting plate, and the axis of the connecting plate is ensured to be in the radial direction. And the welding seam of the connecting plate is controlled according to the standard requirement. The bolt hole on the connecting plate must be accurate, and when welding with shaped steel, must go up, down, left and right alignment fixed back, the side can weld, and after the welding was accomplished, is beaten the bolt hole, is connected the face and is put in order, reduces the error when shaped steel equipment is connected.

The manufactured semi-finished steel products are required to be stored uniformly, steel frames with different radiuses and units are marked, and the semi-finished steel products are convenient to get. And the steel is stored by a lower pad upper cover. The storage field is arranged at a place convenient for transportation as much as possible, so that the steel frame is convenient to carry.

④ Steel arch transportation

The steel frame is transported to a construction site by adopting an 8t Dongfeng dumper, and the processing plant must carefully distribute the steel frame according to the specification of the steel frame when distributing the steel frame. After the steel frame is transported to the working surface, the steel frame is stored in a dry place, is forbidden to be stacked on a wet ground, and is marked clearly. The steel frame specification must be carefully checked before the steel frame is erected by a shift technician, for example, the specification is wrong, and the steel frame must be immediately returned and re-used.

⑤ Steel arch mounting

A. Underdigging treatment and removal of loose rock

The operator checks the underexcavation condition according to the measured paying-off, the underexcavation is within 10cm, the operator who erects the steel frame adopts the crow bar or the pneumatic pick to process, and simultaneously the operator skips and digs the loose stone. And after the blasting operation personnel perform blasting treatment, the personnel for erecting the steel frame check the loosening condition of the rock, clear the loosening rock and ensure the construction safety when erecting the steel frame. After the undermining treatment is finished, a steel frame can be erected by checking the qualified side by field technicians.

B. steel arch frame

The erection of the steel arch is carried out on the trolley. And carrying the section steel to an erection site by 1-2 workers, fastening one end of the section steel by using ropes, lifting the section steel to the working platform by 3-4 workers on the working platform, finding out accurate positioning points according to the design space of the steel frame and the technical intersection record, firstly erecting a steel frame footing section, firstly placing a footing section on the working platform when erecting the footing section, adjusting footing by 2 workers at the lower side, adjusting with a buried reference point, accurately positioning the steel arch, strictly controlling the bottom elevation, processing the over-excavation place at the bottom, and filling the foundation of the section steel to prevent surrounding rock deformation, causing the section steel to sink, and connecting each steel support into a whole through a longitudinal connecting piece and firmly welding with an anchor rod head when erecting the section steel. After the section steel is symmetrically erected, the section steel is erected, when the section steel is erected, an M24 connecting bolt is firstly arranged (not tightened), the section steel is temporarily supported, the connecting steel bar is connected with the section steel of the last truss, another section of section steel is symmetrically arranged, after the installation is completed, the errors of the vault, the two arch feet and the measuring reference point lead wire are inspected, local adjustment is carried out, and finally the bolt is screwed. The operator first performs self-checking, and after the operator is qualified in checking, the operator on duty is notified to check.

The steel support should be installed outside the design section of the lining, and the back of the steel frame must be filled with sprayed concrete to fill the gap between the steel support and the rock face.

(4) Advanced grouting small conduit construction

Because the shield dismantling hole section is IV-level broken surrounding rock, the excavation section is larger and easy to collapse, and the arch part is reinforced by adopting phi 42 advance small guide pipe grouting. The guide pipe is a phi 42 seamless steel pipe, the length of the guide pipe is 3.0m, the external insertion angle is 5-10 degrees, the circumferential spacing is 0.3m, and the longitudinal lap joint length is not less than 1.0 m. The small guide pipe is a hot rolled seamless steel pipe with phi 42mm, the wall thickness is 3.5mm, the front end is made into a sharp cone shape, the tail part is welded with reinforcing hoops with phi 8mm, the pipe wall is drilled with holes with plum blossom shape at intervals of 10-20 cm, the diameter of the holes is 6-8 mm, and the tail part length is not less than 30cm and is used as a slurry stop section without drilling. If necessary, advanced exploratory holes are carried out to predict the phenomena of harmful gas and water gushing in front.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the scope of the invention.

Claims (10)

1. A blasting hole distribution structure for a water delivery tunnel is characterized in that,

The tunnel section is divided into an upper step, a middle step and a lower step from top to bottom; the upper step is divided into at least three parts; the middle step and the lower step are respectively divided into at least two parts;

Each part of the upper step is provided with a cutting eye, an auxiliary eye, a bottom eye and a peripheral eye;

middle eyes, auxiliary eyes, bottom eyes and peripheral eyes are arranged on each part of the middle step and the lower step;

through setting up the position of undercut eye or middle eye, then arrange peripheral eye and bottom eye, finally arrange auxiliary eye according to the section size.

2. The blasting hole distribution structure for the water delivery tunnel according to claim 1, wherein the upper step is composed of a C-shaped section at the top and a D-shaped section at the bottom, and the C-shaped section is divided into three parts, namely ② parts, ① parts and ③ parts in order from left to right, and the D-shaped section is divided into two parts, namely ⑤ parts and ④ parts in order;

The middle step is divided into two parts, namely ⑦ parts and ⑥ parts from left to right in sequence;

The lower step is divided into two parts, namely ⑨ parts and ⑧ parts from left to right.

3. A blasting hole arrangement for a water delivery tunnel according to claim 2, wherein the undercut eye is arranged centrally down the excavation face; the peripheral eyes are arranged on the profile line of the tunneling section and meet the requirements of smooth blasting, and the extrapolation slope of the peripheral eyes is 0.03-0.05.

4. The blasting hole distribution structure for the water delivery tunnel according to claim 2, wherein the slitting holes are wedge-shaped slits, the auxiliary holes are quincuncial uniform holes, and the peripheral holes are light blastholes.

5. A blasting hole arrangement for a water delivery tunnel according to claim 1, wherein the undercut eye and the auxiliary eye each employ uncoupled continuous charges and the peripheral eye employ uncoupled spaced charges; and the small peripheral ocular explosive rolls are bound on the bamboo chips and are charged at intervals.

6. The blasting hole distribution structure for the water delivery tunnel according to claim 1, wherein the upper step adopts a two-stage wedge-shaped cut, the depth of the auxiliary eyelet is 0.5m, and the row spacing is 0.7m; the peripheral holes are light explosion holes, the hole spacing is 0.45m, and the hole depth is 0.5m;

The middle-lower step is provided with the following holes: the row spacing is 0.8m, the auxiliary hole spacing is 0.7m, and the peripheral hole spacing is 0.45m.

7. A rapid construction method for a water transportation tunnel using the blasting hole distribution structure according to any one of claims 1 to 6, comprising the steps of:

S1: and (3) climbing section excavation supporting construction: the method comprises the steps of excavation construction, support construction, climbing section bottom excavation and climbing section second lining;

S2: and (3) shield dismantling hole section excavation supporting construction: including excavation construction and support construction.

8. The rapid construction method for a water tunnel according to claim 7, wherein, in the climbing section excavation supporting construction step,

The excavation construction steps comprise: excavating by adopting a full-section method; adopting a hand drill to drill, explode and excavate, and designing contour line smooth surface blasting; performing field treatment;

The support digging construction steps comprise: preparing construction, steel supporting, foot locking anchor rod construction, steel bar net hanging, connecting ribs, mortar anchor rod and advanced small guide pipe construction, concrete spraying to the design thickness, and next cyclic excavation supporting;

The climbing section bottom excavation step comprises the following steps: the non-excavated part at the bottom of the climbing section is synchronously excavated along with the excavation of the dismantling holes ⑥ part, the ⑦ part, the ⑧ part and the ⑨ part, steel arches with the same model as the upper arches are installed, steel bar meshes are paved and hung, longitudinal connecting ribs are welded, and each arch is divided into a system anchor rod and a foot locking anchor rod, and the system anchor rod and the foot locking anchor rod are sprayed and supported in time;

The step of climbing the second lining of the section comprises the following steps: and pouring the second lining of the transition section by adopting a transport hole second lining trolley, and backfilling light concrete in the cavity at the top.

9. The rapid construction method for a water transport tunnel according to claim 8, wherein in the shield disassembly hole section excavation supporting construction, the excavation construction comprises:

(1) Digging by four steps and nine steps, wherein the hole is in an anchor type;

(2) Adopting a hand drill to drill, explode and excavate, and designing contour line smooth surface blasting;

(3) And (5) field treatment.

10. The rapid construction method for a water delivery tunnel according to claim 9, wherein in the shield-dismantling hole section excavation supporting construction, the supporting construction steps are as follows:

carrying out excavation and support on the ① th part, carrying out excavation and support on the ② th part after the excavation and support on the ① th part is completed by 5-10m, and carrying out the construction method as well as ① th parts; ③ When the part is excavated, firstly, the arch centering at the corresponding position of ① parts is firmly supported by DN89 steel pipes; ④ The temporary support between ①③ parts is lengthened to the bottom of ④ parts during part excavation, and a temporary transverse support is added to the bottom during part ④、⑤ excavation;

Wherein, excavation supporting is divided into four steps and nine steps to sequentially excavate ①-⑨ parts and support, and the excavation supporting interval between each two parts is 5-10 meters.