CN112502743B - Advanced grouting reinforcement method for water-rich sand layer shield zone connecting channel - Google Patents
Advanced grouting reinforcement method for water-rich sand layer shield zone connecting channel Download PDFInfo
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- 230000002787 reinforcement Effects 0.000 title claims abstract description 166
- 238000000034 method Methods 0.000 title claims abstract description 67
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- 239000004576 sand Substances 0.000 title claims abstract description 39
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 71
- 238000010276 construction Methods 0.000 claims abstract description 58
- 238000009412 basement excavation Methods 0.000 claims abstract description 29
- 230000001502 supplementing effect Effects 0.000 claims abstract description 5
- 238000004891 communication Methods 0.000 claims description 80
- 230000008569 process Effects 0.000 claims description 20
- 239000002002 slurry Substances 0.000 claims description 8
- 238000003780 insertion Methods 0.000 claims description 7
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- 230000000694 effects Effects 0.000 abstract description 30
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- 230000006378 damage Effects 0.000 description 3
- 239000003673 groundwater Substances 0.000 description 3
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- 238000001556 precipitation Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
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- 239000007788 liquid Substances 0.000 description 2
- 235000019353 potassium silicate Nutrition 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
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- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 238000007569 slipcasting Methods 0.000 description 1
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- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
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Abstract
The invention discloses a water-rich sand layer shield zone connecting channel advanced grouting reinforcement method, which comprises the following steps: 1. preliminary grouting reinforcement is carried out on stratum at the end part of the channel; 2. grouting and reinforcing the whole channel stratum; 3. and (5) supplementing grouting and reinforcing the stratum at the end part of the channel. The method has the advantages of reasonable design, simple and convenient construction and good reinforcement effect, divides the advanced area to be reinforced of the stratum of the water-rich sand layer connecting channel, adopts a corresponding grouting reinforcement method to effectively reinforce, enables the reinforced stratum and the shield segment of the constructed shield tunnel to be fixedly connected into a whole, can effectively improve the structural stability of the shield tunnel while further improving the reinforcement effect of the stratum of the constructed connecting channel, can effectively limit and even avoid the subsidence of the earth surface of the shield tunnel, lays a foundation for the excavation of the connecting channel, reduces the collapse risk of the connecting channel and ensures the construction safety.
Description
Technical Field
The invention belongs to the technical field of shield interval connection channel construction, and particularly relates to a water-rich sand layer shield interval connection channel advanced grouting reinforcement method.
Background
In subway tunnel construction engineering, a communication channel is required to be arranged in a shield zone for emergency evacuation and drainage. The construction risk of the connecting channel is high, and the connecting channel is always a part with frequent accidents in subway construction. The communication channel accident is liable to cause the destruction of ground cable and the destruction of buildings, even endangering the whole subway line. Therefore, the connection passage construction plays a very important role in the shield construction. However, in the water-rich sand layer area, the problems of loose sand structure, large void ratio, poor stratum self-stability and large excavation risk, how to ensure the construction quality and the safety of the communication channel, become the urgent challenges to be overcome. At present, the conventional construction scheme adopted by underground excavation of the connecting channel in the subway section in the water-rich sand layer is long in period, has serious influence on construction of other working procedures, and is most important in that the construction safety risk is large, and safety accidents are easy to occur. In the aspect of stratum reinforcement, jet grouting piles are mainly adopted at present, the influence on the ground is large in the jet grouting pile reinforcement process, and when the connection channel is large in burial depth, the construction difficulty is large, the input cost is high, and the construction period cannot be effectively ensured.
In the conventional construction of the communication channel, in the aspect of excavation, a weak area of the top support at the joint of the tunnel and the communication channel is excavated in two stages, the part is excavated in two stages, the first stage is excavated obliquely upwards from the elevation of the tunnel portal to the design vault of the communication channel to form a transition section, and the second stage is excavated reversely to the design requirement after the primary support is penetrated, but the method still has great collapse risk under the condition that the stratum is a water-rich sand layer, and the excavation collapse risk of the weak area of the advanced support at the joint of the tunnel and the communication channel is larger due to loose structure of the sand, large void ratio and poor self stability of the stratum, so that a safer advanced grouting reinforcement method for the communication channel in the water-rich sand layer shield zone is needed at present to reduce accidents.
Disclosure of Invention
The technical problem to be solved by the invention is to provide the advanced grouting reinforcement method for the connecting channel between the shield sections of the water-rich sand layer, to divide the advanced area to be reinforced of the stratum of the connecting channel of the water-rich sand layer, and to effectively reinforce by adopting the corresponding type grouting reinforcement method, so that the reinforced stratum and the shield segments of the constructed shield tunnel are fixedly connected into a whole, the structural stability of the shield tunnel can be effectively improved while the stratum reinforcement effect of the constructed connecting channel is further improved, the earth surface subsidence of the shield tunnel can be effectively limited or even avoided, the foundation for excavating the connecting channel is laid, the collapse risk of the connecting channel is reduced, and the construction safety is ensured.
In order to solve the technical problems, the invention adopts the following technical scheme: a water-rich sand layer shield interval connection channel advanced grouting reinforcement method is characterized by comprising the following steps of: the constructed communication channel is a hidden digging channel which is connected between two shield tunnels and the tunnel body of which is positioned in the water-rich sand layer; when the constructed communication channel is pre-reinforced in stratum, the method comprises the following steps:
step one, preliminary grouting reinforcement of stratum at the end part of the channel: carrying out advanced small-conduit grouting reinforcement on stratum at the front end and the rear end of a constructed connecting channel through two shield tunnels respectively, and forming a preliminary reinforcement structure of stratum at the end part of the channel at the outer sides of the two shield tunnels;
step two, grouting and reinforcing the whole channel stratum: respectively carrying out sleeve valve pipe grouting reinforcement on the whole stratum where the constructed communication channel is located through the two shield tunnels to obtain a sleeve valve pipe grouting reinforcement structure;
the preliminary reinforcing structures of the stratum at the end parts of the two channels after construction in the first step are slurry stopping structures when sleeve valve pipe grouting reinforcement is carried out in the first step;
thirdly, supplementing grouting and reinforcing stratum at the end part of the channel: and (3) carrying out supplementary grouting reinforcement on stratum at the front end and the rear end of the constructed communication channel through the advance small guide pipe arranged in the first step and through the two shield tunnels respectively to obtain a stratum grouting reinforcement structure at the end part of the channel, and enabling the stratum grouting reinforcement structure at the end part of the channel to be fixedly connected with the sleeve valve pipe grouting reinforcement structure in the second step into a whole.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the constructed communication channel is horizontally arranged, and the grouting end of the advance small guide pipe is positioned below the vault of the constructed communication channel.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: when preliminary grouting reinforcement is carried out on stratum at the end part of the channel, firstly, a group of advance small guide pipes are respectively arranged on stratum at the front end and the rear end of the constructed communication channel through two shield tunnels, and the two groups of advance small guide pipes are symmetrically arranged; grouting and reinforcing stratum at the front end and the rear end of the constructed communication channel respectively through two groups of the advance small guide pipes;
each group of the leading small guide pipes comprises a plurality of leading small guide pipes which are uniformly distributed on the same plane, and the leading small guide pipes in each group of the leading small guide pipes are distributed from left to right along the width direction of the constructed communication channel and are distributed in parallel; each small advance conduit is arranged along the longitudinal extending direction of the constructed communication channel, one end of each small advance conduit is a stratum driving end driven into the stratum, and the other end of each small advance conduit is a grouting end; each small advance guide pipe gradually inclines upwards from the grouting end to the stratum driving end;
And in the third step, when the supplementary grouting reinforcement is carried out, the two groups of the advanced small guide pipes are used for respectively carrying out the supplementary grouting reinforcement on the stratum at the front end and the back end of the constructed communication channel.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: when preliminary grouting reinforcement is carried out on the stratum at the end part of the channel, stopping grouting when grouting pressure of all the advance small guide pipes in the two groups of the advance small guide pipes reaches P1, and finishing the preliminary grouting reinforcement process of the stratum at the end part of the channel; wherein P1 is a preset preliminary grouting pressure value, and the value range of P1 is 0.7 MPa-0.8 MPa;
stopping grouting when the grouting pressure of all the leading small pipes in the two groups of leading small pipes reaches P2 during the supplementary grouting reinforcement in the third step, and completing the supplementary grouting reinforcement process; wherein P2 is a preset supplementary grouting pressure value, and the value range of P2 is 0.5MPa to 0.6MPa.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the areas where the two shield tunnels are connected with the constructed connecting channel are tunnel connection areas, and each group of small advance guide pipes are uniformly distributed on the outer side of one tunnel connection area; the distance D between the two leading small pipes positioned at the leftmost side and the rightmost side in each group of leading small pipes is larger than the excavation width of the constructed communication channel;
The number of the advance small pipes included in each group of the advance small pipes is 2M, wherein M is a positive integer and is more than or equal to 3; the number of the leading small guide pipes positioned at the left and right sides of the central line of the constructed communication channel tunnel in each group is M;
and in the first step and the third step, grouting is symmetrically performed on the left side and the right side from the middle part respectively when grouting is performed through any group of the advance small guide pipes.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the advanced small guide pipe arranged in the first step is a grouting pipe which is driven into the stratum through a pipe piece lifting hole on a shield pipe piece ring in the shield tunnel.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: before sleeve valve pipe grouting reinforcement is carried out in the second step, the front sleeve valve pipe grouting structure and the rear sleeve valve pipe grouting structure are respectively constructed through two shield tunnels, the two sleeve valve pipe grouting structures are symmetrically distributed and are grouting reinforcement structures for integrally reinforcing a stratum to be reinforced; each sleeve valve pipe grouting structure comprises a plurality of sleeve valve pipes which are driven into the ground to be reinforced from the same shield tunnel, and the sleeve valve pipes in each sleeve valve pipe grouting structure are radially distributed; the stratum to be reinforced is a stratum within the range of L meters outside the excavation contour line of the constructed communication channel, wherein the value range of L is 2.5-3.5;
Each sleeve valve tube in one sleeve valve tube grouting structure is intersected with at least one sleeve valve tube in the other sleeve valve tube grouting structure.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the stratum to be reinforced is divided into a heavy overlaying and reinforcing area, an outer grouting weak area positioned at the outer side of the overlaying and reinforcing area and two end grouting weak areas positioned at the front side and the rear side of the overlaying and reinforcing area respectively, and the overlaying and reinforcing area is an area where grouting areas of the two sleeve valve pipe grouting structures are overlapped;
the two end grouting weak areas are respectively positioned above the front end and the rear end of the overlapped reinforcing area, and the advance small guide pipe arranged in the first step is positioned in the end grouting weak area; the two end grouting weak areas are all advanced small conduit grouting reinforcing areas which are reinforced by adopting advanced small conduits, and the overlapping reinforcing areas and the two end grouting weak areas form a core reinforcing area;
and the stratum where the constructed connecting channel body is positioned in the core reinforcing area.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the tunnel hole of the constructed communication channel is divided into a lower hole body and an upper hole body positioned above the lower hole body;
Each sleeve valve pipe grouting structure comprises a plurality of groups of upper sleeve valve pipes for reinforcing a stratum to be reinforced in the area where the upper hole body is located and a plurality of groups of lower sleeve valve pipes for reinforcing a stratum to be reinforced in the area where the lower hole body is located, wherein the plurality of groups of upper sleeve valve pipes and the plurality of groups of lower sleeve valve pipes are all arranged from inside to outside; each group of upper sleeve valve pipes comprises a plurality of sleeve valve pipes which are distributed along the excavation outline of the upper hole body, and the sleeve valve pipe external insertion angles of a plurality of groups of upper sleeve valve pipes are gradually increased from inside to outside; each group of lower sleeve valve pipes comprises a plurality of sleeve valve pipes which are distributed along the excavation outline of the lower hole body, and the sleeve valve pipe external insertion angles of a plurality of groups of lower sleeve valve pipes are gradually increased from inside to outside;
in the second step, in the sleeve valve pipe grouting reinforcement process, grouting reinforcement is carried out from outside to inside when sleeve valve pipe grouting reinforcement is carried out through any sleeve valve pipe grouting structure.
The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the two shield tunnels are connected with the constructed connecting channel in a tunnel connection area, and a plurality of sleeve valve pipe mounting holes for the sleeve valve pipe to be arranged are formed in the shield segment rings of the tunnel connection area in the two shield tunnels.
Compared with the prior art, the invention has the following advantages:
1. the method has the advantages of simple steps, reasonable design, simple construction and low input cost.
2. The adopted end stratum grouting reinforcement method is simple and convenient to implement, the grouting process is easy to control, the reinforcement effect is good, the advance small guide pipe adopted in the end stratum grouting reinforcement is simple and convenient to set and has good reinforcement effect, a stable-structure grouting stop ring is formed before the whole reinforcement of the communication channel stratum, the end stratum of the communication channel can be effectively reinforced, and meanwhile, the end stratum grouting reinforcement and sleeve valve pipe grouting reinforcement are mutually supplemented, so that the final reinforcement effect of the communication channel stratum can be effectively enhanced; moreover, the shield tunnel can be effectively reinforced from the outside through end stratum grouting reinforcement, and the reinforcement quality and the connection effect of the joint of the shield tunnel and the connecting channel can be ensured; in addition, through tip stratum slip casting reinforcement can be with connection passageway stratum reinforced structure and both ends shield tunnel fastening connection as an organic whole, further ensure shield tunnel and connection passageway's whole reinforcement effect to can be with shield tunnel's whole stability. According to the invention, the stratum primary reinforcing structures at the end parts of the channels are arranged to symmetrically reinforce the stratum at the front and rear ends of the constructed connecting channel, and meanwhile, the two symmetrical slurry stopping rings are formed by the stratum primary reinforcing structures at the end parts of the two channels, so that slurry backflow in the whole grouting reinforcing and grouting process of the stratum of the channels can be prevented, underground water flows at the front and rear ends of the constructed connecting channel can be effectively cut off, the structural stability of the joint between the constructed connecting channel and two shield tunnels is ensured, and the construction safety is ensured.
3. The sleeve valve pipe grouting reinforcement method is simple and convenient to implement, the grouting process is easy to control, the reinforcement effect is good, the sleeve valve pipe grouting reinforcement structure formed by construction integrally and effectively reinforces the stratum where the constructed communication channel is located, the radial grouting reinforcement mode can fulfill the aim of reinforcing the stratum where the constructed communication channel is located in a full range, and the integral reinforcement effect is very good; the arrangement space of the advanced small guide pipes in the stratum at the two ends of the constructed communication channel is smaller, so that grouting density and grouting reinforcement effect in the stratum at the two ends of the constructed communication channel can be effectively ensured; while the leading small guide pipes in the middle part of the constructed communication channel are arranged at larger intervals, the leading small guide pipes on the front side and the rear side in the middle part of the constructed communication channel are mutually intersected, so that the grouting density and grouting reinforcement effect in the stratum can be ensured.
4. When the grouting reinforcement is carried out by adopting the method, the grouting reinforcement of the small advanced guide pipe at the end part of the connecting channel is combined with the integral reinforcement of the sleeve valve pipe of the stratum of the connecting channel, the construction is simple and convenient, the reinforcement quality is convenient to control, after the grouting reinforcement is finished, the reinforced stratum and the shield segment in the constructed shield tunnel are fixedly connected into a whole, the structure stability of the shield tunnel can be effectively improved while the stratum reinforcement effect of the area where the constructed connecting channel is positioned is further improved, and the earth surface subsidence of the shield tunnel can be effectively limited or even avoided. The communication channel pre-reinforcement stratum in the water-rich sand layer area is divided into a plurality of reinforcement areas, and stratum pre-reinforcement construction is carried out on different reinforcement areas by adopting different reinforcement methods, so that the communication channel pre-reinforcement stratum is simply, conveniently, quickly and reliably reinforced, a foundation is laid for excavation of a subsequent communication channel, collapse risk during excavation of the communication channel is reduced, and construction safety is guaranteed.
In summary, the method has simple steps, reasonable design, simple construction and good reinforcement effect, divides the advanced area to be reinforced of the stratum of the water-rich sand layer connecting channel, adopts the grouting reinforcement method of the corresponding type to effectively reinforce, enables the reinforced stratum and the shield segment of the constructed shield tunnel to be fixedly connected into a whole, can effectively improve the structural stability of the shield tunnel while further improving the reinforcement effect of the stratum of the constructed connecting channel, can effectively limit and even avoid the subsidence of the earth surface of the shield tunnel, lays a foundation for excavating the connecting channel, reduces the collapse risk of the connecting channel and ensures the construction safety.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a construction state diagram of the present invention when the stratum of the connecting passage is pre-reinforced.
FIG. 2 is a schematic diagram of the layout positions of the advance small catheter and the sleeve valve tube on the cross section of the shield tunnel.
FIG. 3 is a schematic layout of the upper sleeve valve tube, the advance small conduit and the portal in the cross section of the communication channel of the present invention.
Fig. 4 is a flow chart of the method of the present invention.
Reference numerals illustrate:
1-shield tunneling; 2-a communication channel; 3-a tunnel portal;
4-sleeve valve tube; 5-stratum to be reinforced; 6-overlapping the reinforced areas;
7-end grouting weak areas; 8-leading small catheter; 9-outside grouting weak area.
Detailed Description
The method for reinforcing the advanced grouting of the connecting channel in the shield section of the water-rich sand layer is shown in fig. 4, wherein the constructed connecting channel 2 is a hidden digging channel which is connected between two shield tunnels 1 and is positioned in the water-rich sand layer, and the details are shown in fig. 1; when the constructed communication channel 2 is pre-reinforced in stratum, the method comprises the following steps:
step one, preliminary grouting reinforcement of stratum at the end part of the channel: carrying out advanced small-conduit grouting reinforcement on stratum at the front end and the rear end of a constructed connecting channel 2 through two shield tunnels 1 respectively, and forming a primary reinforcing structure of the stratum at the end part of the channel at the outer sides of the two shield tunnels 1;
step two, grouting and reinforcing the whole channel stratum: the sleeve valve pipe grouting reinforcement structure is obtained by respectively carrying out sleeve valve pipe grouting reinforcement on the whole stratum where the constructed communication channel 2 is located through the two shield tunnels 1;
the preliminary reinforcing structures of the stratum at the end parts of the two channels after construction in the first step are slurry stopping structures when sleeve valve pipe grouting reinforcement is carried out in the first step;
Thirdly, supplementing grouting and reinforcing stratum at the end part of the channel: and (3) carrying out supplementary grouting reinforcement on stratum at the front end and the rear end of the constructed communication channel 2 through the advance small guide pipe 8 arranged in the first step and through the two shield tunnels 1 respectively to obtain a stratum grouting reinforcement structure at the end part of the channel, and enabling the stratum grouting reinforcement structure at the end part of the channel to be fixedly connected with the sleeve valve pipe grouting reinforcement structure in the second step into a whole.
Wherein, the water-rich sand layer refers to a sand layer positioned below the groundwater level.
In this embodiment, the constructed communication channel 2 is located below the groundwater level.
Because the constructed connecting channel 2 is connected between the two constructed shield tunnels 1, in order to avoid adverse effects on the structural stability of the two shield tunnels 1, the ground subsidence of the area where the two shield tunnels 1 are positioned and the like in the precipitation construction process, the stratum of the construction area where the constructed connecting channel 2 is positioned is not subjected to precipitation before the stratum is subjected to grouting reinforcement by adopting the method.
The grouting reinforcement is carried out by adopting the method, the construction is simple and convenient, the reinforcement quality is convenient to control, after the grouting reinforcement is finished, the reinforced stratum and the shield segment in the constructed shield tunnel 1 are fixedly connected into a whole, the stratum reinforcement effect of the area where the constructed communication channel 2 is positioned is further improved, the structural stability of the shield tunnel 1 can be effectively improved, and the earth surface subsidence of the shield tunnel 1 can be effectively limited or even avoided.
According to the method, the pre-reinforced stratum of the connecting channel 2 in the water-rich sand layer area is divided into a plurality of reinforced areas, and stratum pre-reinforcement construction is carried out on different reinforced areas by adopting different reinforcement methods, so that stable reinforcement of the pre-reinforced stratum of the connecting channel 2 is realized, a foundation is laid for excavation of the subsequent connecting channel 2, collapse risk during excavation of the connecting channel 2 is reduced, and construction safety is guaranteed.
In this embodiment, the constructed communication channel 2 is arranged horizontally, and the grouting end of the advance small pipe 8 is positioned below the vault of the constructed communication channel 2.
And the two shield tunnels 1 are connected with the constructed connecting passage 2, and the areas are provided with the portal 3 of the constructed connecting passage 2.
After preliminary grouting reinforcement is completed in the first step, the stratum at the front end and the back end of the constructed connecting channel 2 is symmetrically reinforced through two symmetrical channel end stratum preliminary reinforcing structures, and simultaneously, two symmetrical grout stopping rings are formed by the channel end stratum preliminary reinforcing structures, so that grout backflow in the whole grouting reinforcement grouting process of the channel stratum in the second step can be prevented, underground water flows at the front end and the back end of the constructed connecting channel 2 can be effectively intercepted, the structural stability of the joint between the constructed connecting channel 2 and the two shield tunnels 1 is ensured, and the construction safety is ensured.
It should be noted that, preliminary reinforced structure of passageway tip stratum wraps up the stratum of connection passageway 2 gradual change excavation changeover portion, and the stratum that is located gradual change excavation changeover portion top when preventing gradual change excavation changeover portion back dig consolidates inadequately, guarantees the safety of follow-up connection passageway 2 excavation at any moment.
In this embodiment, referring to fig. 1, fig. 2 and fig. 3, when the formation at the end of the tunnel is primarily grouting and reinforced in the first step, a group of small advance pipes 8 are respectively arranged at the front end and the rear end of the constructed connecting tunnel 2 through two shield tunnels 1, and the two groups of small advance pipes 8 are symmetrically arranged; grouting and reinforcing stratum at the front end and the rear end of the constructed communication channel 2 respectively through two groups of small advance guide pipes 8;
each group of the advance small guide pipes 8 comprises a plurality of advance small guide pipes 8 which are uniformly distributed on the same plane, and the plurality of the advance small guide pipes 8 in each group of the advance small guide pipes 8 are distributed from left to right along the width direction of the constructed communication channel 2 and are distributed in parallel; each small leading guide pipe 8 is arranged along the longitudinal extending direction of the constructed communication channel 2, one end of each small leading guide pipe 8 is a stratum driving end driven into the stratum, and the other end of each small leading guide pipe is a grouting end; each of the small advance guide pipes 8 is gradually inclined upward from the grouting end to the stratum driving end;
And in the third step, when the supplementary grouting reinforcement is carried out, the two groups of leading small guide pipes 8 are used for respectively carrying out the supplementary grouting reinforcement on stratum at the front end and the back end of the constructed communication channel 2.
In actual construction, the two groups of the advance small guide pipes 8 are arranged simply and conveniently, and the construction is convenient.
The stratum driving end of the advance small guide pipe 8 is positioned above the vault of the constructed communication channel 2, and the vertical distance between the stratum driving end and the vault is 0.5 m-2 m.
In this embodiment, the vertical distance between the ground driving end of the leading small pipe 8 and the dome of the constructed communication passage 2 is 1.5m. Therefore, the advance small guide pipe 8 is adopted to carry out grouting reinforcement within the range of 1.5m outside the two ends of the constructed connecting channel 2.
In the actual construction process, the vertical distance between the stratum driving end of the advance small guide pipe 8 and the vault of the constructed communication channel 2 can be correspondingly adjusted according to specific requirements.
From the above, the preliminary reinforcement structure of the stratum at the end of the passage in the first step is a leading small conduit grouting support structure. Therefore, grouting is carried out according to a conventional advanced small catheter grouting method in the first step, the actual construction is simple and convenient, and the grouting reinforcement effect is good.
In this embodiment, the constructed communication channel 2 is laid horizontally.
It should be noted that, because the stratum at the end of the passage near the side wall of the segment of the shield tunnel 1 is often provided with a water flow passage, when the sleeve valve pipe 4 which is arranged by punching on the opposite side portal 3 is adopted for reinforcement, the grouting effect of the stratum driving end is not good because the sleeve valve pipe 4 is long, and the two factors act together, so that the unset slurry is easily flushed away by water flow when the stratum at the end of the passage is reinforced by grouting through the sleeve valve pipe 4, so the grouting effect of the sleeve valve pipe 4 is very poor; furthermore, because the position is positioned at the top of the tunnel portal 3 and is close to the outer side wall of the segment of the shield tunnel 1, collapse risks exist at the position where the connecting channel is excavated, the reinforcing effect of the stratum can be guaranteed only by the extra grouting of the advanced small guide pipe 8, and the excavation safety of the subsequent connecting channel is guaranteed.
After the preliminary grouting reinforcement of the stratum at the end part of the channel is completed in the first step, the preliminary reinforcement structure of the stratum at the end part of the channel after construction is completed has the following beneficial effects: firstly, the reinforcement effect of the subsequent sleeve valve pipe grouting reinforcement can be effectively enhanced, the two preliminary reinforcement structures of the stratum at the end part of the channel can be used as a grouting stopping structure when the sleeve valve pipe grouting reinforcement is carried out in the second step, and leakage is prevented, so that the grouting density and the grouting pressure of the sleeve valve pipe grouting are effectively improved, and the sleeve valve pipe grouting reinforcement strength is enhanced; secondly, the shield tunnels 1 on the two sides can be effectively protected, and any adverse effect on the shield tunnels 1 on the two sides in the subsequent construction process is prevented; thirdly, the shield segments at the joint between the two side shield tunnels 1 and the constructed connecting channel 2 are effectively reinforced, so that the construction quality of the joint between the constructed connecting channel 2 and the two side shield tunnels 1 can be effectively improved; fourthly, groundwater above the joint between the shield tunnel 1 and the constructed connecting channel 2 can be effectively intercepted, so that the construction quality of the joint between the shield tunnels 1 and the constructed connecting channel 2 on two sides is further ensured, the construction difficulty and the construction risk are reduced, the construction period is effectively saved, and the grouting reinforcement effect of the subsequent sleeve valve pipe can be further enhanced; meanwhile, the subsequent precipitation effect can be effectively improved; fifth, the preliminary stratum reinforcing structures at the end parts of the channels and the sleeve valve pipe grouting reinforcing structures can be fastened and connected into a whole to form an integral reinforcing structure which is fastened and connected between the two shield tunnels 1, so that the integrity and the stability of the shield tunnels 1 at the two sides and the constructed connecting channel 2 can be effectively enhanced, and the long-term use effect is ensured; sixth, as the stratum at the two ends of the constructed connecting channel 2 is a reinforced weak area for grouting reinforcement of the subsequent sleeve valve pipe, the defect of grouting reinforcement of the subsequent sleeve valve pipe can be effectively overcome through preliminary grouting reinforcement of the stratum at the end part of the channel.
After the grouting reinforcement of the sleeve valve pipe is completed, the sleeve valve pipe grouting reinforcement structure integrally and effectively reinforces the stratum where the constructed communication channel 2 is located, the sleeve valve pipe grouting reinforcement structure adopts a radial grouting reinforcement mode, the purpose of reinforcing the stratum where the constructed communication channel 2 is located in a full range can be met, and the integral reinforcement effect is very good; the arrangement space of the advance small guide pipes 8 in the stratum at the two ends of the constructed communication channel 2 is smaller, so that grouting density and grouting reinforcement effect in the stratum at the two ends of the constructed communication channel 2 can be effectively ensured; while the leading small guide pipes 8 in the middle part of the constructed communication channel 2 are arranged at larger intervals, the leading small guide pipes 8 on the front side and the rear side of the middle part of the constructed communication channel 2 are mutually intersected, so that the grouting density and grouting reinforcement effect in the stratum can be ensured as well.
And thirdly, after the supplementary grouting reinforcement is carried out, the preliminary grouting reinforcement effect of the stratum at the end part of the channel in the first step is further enhanced, and the overall reinforcement effect of the stratum where the constructed communication channel 2 is located can be further enhanced.
In order to control the process simply and conveniently, when the preliminary grouting reinforcement of the stratum at the end part of the channel is carried out in the first step, stopping grouting when the grouting pressure of all the advance small guide pipes 8 in the two groups of the advance small guide pipes 8 reaches P1, and completing the preliminary grouting reinforcement process of the stratum at the end part of the channel; wherein P1 is a preset preliminary grouting pressure value, and the value range of P1 is 0.7 MPa-0.8 MPa;
In the third step, when the supplementary grouting reinforcement is carried out, stopping grouting when the grouting pressure of all the leading small pipes 8 in the two groups of leading small pipes 8 reaches P2, and completing the supplementary grouting reinforcement process; wherein P2 is a preset supplementary grouting pressure value, and the value range of P2 is 0.5MPa to 0.6MPa.
In this example, p1=0.75 MPa and p2=0.55 MPa. In actual construction, the values of P1 and P2 can be correspondingly adjusted according to specific requirements.
In this embodiment, the areas where the two shield tunnels 1 are connected with the constructed connecting channel 2 are tunnel connection areas, and each group of the advance small pipes 8 are uniformly distributed outside one tunnel connection area; the distance D between the two leading small pipes 8 positioned at the leftmost side and the rightmost side in each group of the leading small pipes 8 is larger than the excavation width of the constructed communication channel 2;
the number of the advance small pipes 8 included in each group of the advance small pipes 8 is 2M, wherein M is a positive integer and M is more than or equal to 3; the number of the leading small pipes 8 positioned at the left and right sides of the central line of the tunnel of the constructed communication channel 2 in each group is M;
and in the first step and the third step, grouting is performed symmetrically from the middle to the left and right sides respectively when grouting is performed through any group of the advance small guide pipes 8.
Wherein D is 6 m-12 m larger than the excavation width of the constructed connecting channel 2.
In this embodiment, m=4. And d=16m.
In actual construction, the values of M and D can be correspondingly adjusted according to specific requirements.
In practical construction, all the advance small pipes 8 in each group of the advance small pipes 8 have the same size and the same layout height. The included angles between the plurality of the leading small pipes 8 in each group of the leading small pipes 8 and the horizontal plane are the same, and the grouting ends of all the leading small pipes 8 in each group of the leading small pipes 8 are positioned on the same horizontal plane.
In this embodiment, the included angle between the small advancing pipe 8 and the horizontal plane (i.e., the external inserting angle of the small advancing pipe 8) is 15 ° to 30 °.
In this embodiment, the advance small conduit 8 arranged in the first step is a grouting pipe driven into the stratum through a pipe piece lifting hole on a shield pipe piece ring in the shield tunnel 1.
It should be noted that, the advanced small conduit 8 is arranged through the pipe piece lifting hole, so that the integrity of the pipe piece ring is ensured to a great extent, the entity quality of the shield tunnel 1 is ensured, and the safety and stability of the tunnel structure are ensured.
In the embodiment, before grouting reinforcement of sleeve valve pipes in the second step, the front and rear sleeve valve pipe grouting structures are respectively constructed through two shield tunnels 1, and the two sleeve valve pipe grouting structures are symmetrically distributed and are grouting reinforcement structures for integrally reinforcing the stratum 5 to be reinforced; each sleeve valve pipe grouting structure comprises a plurality of sleeve valve pipes 4 driven into a stratum 5 to be reinforced from the same shield tunnel 1, and the sleeve valve pipes 4 in each sleeve valve pipe grouting structure are distributed radially; the stratum 5 to be reinforced is a stratum within the range of L meters outside the excavation contour line of the constructed connecting channel 2, wherein the value range of L is 2.5-3.5;
Each sleeve 4 in one sleeve grouting structure crosses at least one sleeve 4 in the other sleeve grouting structure.
In this embodiment, the value of L is 3. Thus, the formation 5 to be reinforced is a formation within 3 meters outside the excavated contour of the constructed connecting channel 2.
During actual construction, the value of L can be correspondingly adjusted according to specific requirements.
In this embodiment, the stratum to be reinforced 5 is divided into a overlapping reinforcing region 6, an outer grouting weak region 9 located at the outer side of the overlapping reinforcing region 6, and two end grouting weak regions 7 located at the front and rear sides of the overlapping reinforcing region 6, where the overlapping reinforcing region 6 is a region where grouting regions of two sleeve valve pipe grouting structures overlap;
the two end grouting weak areas 7 are respectively positioned above the front end and the rear end of the overlapped reinforcing area 6, and the advance small guide pipe 8 arranged in the first step is positioned in the end grouting weak areas 7; the two end grouting weak areas 7 are all advanced small guide pipe grouting reinforcing areas reinforced by adopting an advanced small guide pipe 8, and the overlapping reinforcing areas 6 and the two end grouting weak areas 7 form a core reinforcing area;
the stratum where the constructed connecting channel 2 is located in the core reinforcing area.
In actual construction, all the leading small ducts 8 in each group of the leading small ducts 8 are located in the same end grouting weak area 7.
It should be noted that, the outer grouting weak area 9 and the end grouting weak area 7 are non-overlapping areas of grouting areas of the two sleeve valve pipe grouting structures, and because the end grouting weak area 7 is more prone to collapse, the reinforcing effect of the non-overlapping areas of grouting areas of the two sleeve valve pipe grouting structures can meet the formation reinforcing requirement of the outer grouting weak area 9 but cannot meet the formation reinforcing requirement of the end grouting weak area 7, and therefore the end grouting weak area 7 needs to be additionally subjected to grouting reinforcing construction by the advance small guide pipe 8.
The outside grouting weak area 9 does not carry out grouting reinforcement additionally when stratum is pre-reinforced, construction period is saved, the outside grouting weak area 9 can be reinforced again through the advance small guide pipes which are arranged on the vault of the channel in a beating mode and are parallel to each other when the communication channel 2 is initially supported, and stability of the communication channel is guaranteed.
In this embodiment, the tunnel hole of the constructed communication channel 2 is divided into a lower hole body and an upper hole body located above the lower hole body;
each sleeve valve pipe grouting structure comprises a plurality of groups of upper sleeve valve pipes for reinforcing a stratum 5 to be reinforced in the area where the upper hole body is located and a plurality of groups of lower sleeve valve pipes for reinforcing the stratum 5 to be reinforced in the area where the lower hole body is located, wherein the plurality of groups of upper sleeve valve pipes and the plurality of groups of lower sleeve valve pipes are all distributed from inside to outside; each group of upper sleeve valve pipes comprises a plurality of sleeve valve pipes 4 which are distributed along the excavation outline of the upper hole body, and the external insertion angles of the sleeve valve pipes 4 of a plurality of groups of upper sleeve valve pipes are gradually increased from inside to outside; each group of lower sleeve valve pipes comprises a plurality of sleeve valve pipes 4 which are distributed along the excavation outline of the lower hole body, and the external insertion angles of the sleeve valve pipes 4 of a plurality of groups of lower sleeve valve pipes are gradually increased from inside to outside;
In the second step, in the sleeve valve pipe grouting reinforcement process, grouting reinforcement is carried out from outside to inside when sleeve valve pipe grouting reinforcement is carried out through any sleeve valve pipe grouting structure.
Wherein, the external insertion angle of the sleeve valve tube 4 refers to the included angle between the sleeve valve tube 4 and the central axis of the constructed communication channel 2. The external insertion angle of the sleeve valve tube 4 is not more than 30 degrees.
In this embodiment, the areas where the two shield tunnels 1 are connected with the constructed connecting channel 2 are tunnel connection areas, and the shield segment rings of the tunnel connection areas in the two shield tunnels 1 are provided with a plurality of sleeve valve tube mounting holes for the sleeve valve tubes 4 to be arranged.
And the tunnel connection areas in the two shield tunnels 1 are provided with a portal 3 of the constructed communication channel 2, the opening area of the portal 3 on the shield segment in the shield tunnel 1 is a portal opening area, and the sleeve valve tube mounting hole is positioned in the portal opening area.
It should be noted that, in order to ensure the integrity of the segment of the shield tunnel 1 except the region where the portal is opened, the sleeve valve tube 4 in the pre-reinforcing process of the formation of the connecting channel 2 can only be set into the formation by the region where the portal is opened, and the maximum elevation angle of the sleeve valve tube 4 is limited by the limit, so that the sleeve valve tube 4 cannot penetrate into the connection region between the shield tunnel 1 and the connecting channel 2, and the grouting of the sleeve valve tube 4 cannot completely cover the preset formation 5 to be reinforced of the connecting channel 2, thereby the end grouting weak region 7 occurs.
In this embodiment, the angle of the outer sleeve 4 above the portal 3 is in the range of 25 ° to 30 °.
When the constructed communication channel 2 is actually excavated, the construction is performed from the rear to the front along the longitudinal extending direction. In order to ensure the structural stability of the joint between the constructed connecting channel 2 and the shield tunnel 1 and reduce the construction risk, the portal 3 positioned at the rear side of the constructed connecting channel 2 is rectangular, and the portal opening area positioned in the shield tunnel 1 at the rear side of the constructed connecting channel 2 is rectangular and has the same structure and size as the portal 3. The width of the cavity door 3 positioned at the rear side of the constructed communication channel 2 is smaller than the excavation width of the constructed communication channel 2, and the height of the cavity door 3 is smaller than the excavation height of the constructed communication channel 2. At the same time, the roof of the portal 3 at the rear side of the constructed communication channel 2 is lower than the dome of the constructed communication channel 2. The grouting end of the leading small conduit 8 is positioned above the tunnel portal 3, and the grouting end of the leading small conduit 8 is positioned below the vault of the constructed communication channel 2.
In this embodiment, a plurality of the advance small pipes 8 in each group of the advance small pipes 8 are uniformly distributed, the distance between two adjacent advance small pipes 8 is the same as the distance between two adjacent shield segment rings in the shield tunnel 1, and the grouting end of each advance small pipe 8 is supported on one shield segment ring.
And in the second step, the conventional sleeve valve pipe grouting reinforcement method is adopted when sleeve valve pipe grouting is carried out. The length of the constructed connecting channel 2 is 10 m-20 m. In the embodiment, the buried depth of the constructed communication channel 2 is 11.55m, the length is 15.80m, the section size is 3.80m multiplied by 4.57m, the mixed filling soil, the silt and the middle sand are distributed from top to bottom, the stable water level buried depth of the underground water is between 10.30m and 11.80m, and the cavity of the constructed communication channel 2 is positioned in the water-rich middle sand layer.
In the embodiment, the sleeve valve tube 4 is a PVC tube with the diameter phi of 48mm, the interval is 300mm multiplied by 300mm, the grouting liquid is cement-water glass double-liquid slurry, the volume ratio of cement to water glass is 1:1, the water glass concentration is 35Be, the water-cement ratio of cement is 1:1, the normal diffusion of the slurry is ensured, and the grouting is performed in a mode of gradually increasing the pressure. And in the second step, when sleeve valve pipe grouting is carried out, the reinforcement range is 3m outside the tunnel outline of the constructed communication channel 2.
In this embodiment, the small advance pipe 8 is a steel pipe with a diameter Φ50mm and a length of 2 m. The grout injected into the small advance pipe 8 is the same as that injected into the sleeve valve tube 4.
In summary, when grouting is performed in the first step, the second step and the third step, grouting is performed in a hole (namely, in a tunnel hole of the shield tunnel 1), grouting is simple and convenient, grouting reinforcement is not needed from outside the hole (namely, the ground), construction cost can be reduced, construction period is saved, the problems that the ground is greatly influenced, construction difficulty is high, input cost is high, construction period cannot be effectively ensured and the like in the existing jet grouting pile reinforcement process can be effectively avoided, and the stratum where the constructed connecting channel 2 is located can be effectively reinforced while the stratum where the two shield tunnels 1 are connected with the constructed connecting channel 2 is simultaneously reinforced; meanwhile, the shield tunnel 1 can be effectively reinforced, and particularly the shield segment ring at the joint between the two shield tunnels 1 and the constructed connecting channel 2 can be effectively reinforced. In addition, the leading small guide pipe 8 is inserted into the stratum through the pipe piece lifting hole, and the sleeve valve pipe 4 is inserted into the stratum through the tunnel portal opening area, so that the leading small guide pipe 8 and the sleeve valve pipe 4 are arranged so as not to cause any damage to the shield pipe piece ring of the shield tunnel 1, the integrity of the pipe piece ring is ensured to a great extent, the entity quality of the shield tunnel 1 is ensured, and the safety and stability of the tunnel structure are ensured.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modification, variation and equivalent structural changes made to the above embodiment according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (6)
1. A water-rich sand layer shield interval connection channel advanced grouting reinforcement method is characterized by comprising the following steps of: the constructed connecting channel (2) is a hidden digging channel which is connected between two shield tunnels (1) and the tunnel body of which is positioned in the water-rich sand layer; when the constructed connecting channel (2) is pre-reinforced in stratum, the method comprises the following steps:
step one, preliminary grouting reinforcement of stratum at the end part of the channel: carrying out advanced small-conduit grouting reinforcement on stratum at the front end and the rear end of a constructed connecting channel (2) through two shield tunnels (1), and forming a preliminary reinforcing structure of the stratum at the end part of the channel at the outer sides of the two shield tunnels (1);
step two, grouting and reinforcing the whole channel stratum: respectively grouting and reinforcing sleeve valve pipes on the whole stratum where the constructed connecting channel (2) is located through the two shield tunnels (1) to obtain a sleeve valve pipe grouting and reinforcing structure;
the preliminary reinforcing structures of the stratum at the end parts of the two channels after construction in the first step are slurry stopping structures when sleeve valve pipe grouting reinforcement is carried out in the first step;
Thirdly, supplementing grouting and reinforcing stratum at the end part of the channel: supplementing grouting reinforcement is carried out on stratum at the front end and the rear end of a constructed connecting channel (2) through an advance small conduit (8) arranged in the first step and through two shield tunnels (1) respectively to obtain a stratum grouting reinforcement structure at the end part of the channel, and the stratum grouting reinforcement structure at the end part of the channel is fastened and connected with the sleeve valve pipe grouting reinforcement structure in the second step into a whole;
the constructed connecting channel (2) is horizontally arranged, and the grouting end of the advance small guide pipe (8) is positioned below the vault of the constructed connecting channel (2);
when preliminary grouting reinforcement is carried out on stratum at the end part of the channel, firstly, a group of advance small guide pipes (8) are respectively arranged on stratum at the front end and the rear end of the constructed connecting channel (2) through two shield tunnels (1), and the two groups of advance small guide pipes (8) are symmetrically arranged; grouting and reinforcing stratum at the front end and the rear end of the constructed connecting channel (2) respectively through two groups of small advance guide pipes (8);
each group of the advance small guide pipes (8) comprises a plurality of advance small guide pipes (8) which are uniformly distributed on the same plane, and the plurality of the advance small guide pipes (8) in each group of the advance small guide pipes (8) are distributed from left to right along the width direction of the constructed communication channel (2) and are distributed in parallel; each small leading conduit (8) is arranged along the longitudinal extending direction of the constructed connecting channel (2), one end of each small leading conduit (8) is a stratum driving end driven into the stratum, and the other end of each small leading conduit is a grouting end; each leading small guide pipe (8) gradually inclines upwards from the grouting end to the stratum driving end;
In the third step, when the supplementary grouting reinforcement is carried out, the two groups of leading small guide pipes (8) are used for respectively carrying out supplementary grouting reinforcement on stratum at the front end and the back end of the constructed connecting channel (2);
before sleeve valve pipe grouting reinforcement is carried out in the second step, the front sleeve valve pipe grouting structure and the rear sleeve valve pipe grouting structure are respectively constructed through the two shield tunnels (1), and the two sleeve valve pipe grouting structures are symmetrically distributed and are grouting reinforcement structures for integrally reinforcing a stratum (5) to be reinforced; each sleeve valve pipe grouting structure comprises a plurality of sleeve valve pipes (4) driven into a stratum (5) to be reinforced from the same shield tunnel (1), and the sleeve valve pipes (4) in each sleeve valve pipe grouting structure are radially distributed; the stratum (5) to be reinforced is a stratum within the range of L meters outside the excavation contour line of the constructed connecting channel (2), wherein the value range of L is 2.5-3.5;
each sleeve valve tube (4) in one sleeve valve tube grouting structure is intersected with at least one sleeve valve tube (4) in the other sleeve valve tube grouting structure;
the stratum to be reinforced (5) is divided into a heavy overlaying and reinforcing area (6), an outer grouting weak area (9) positioned at the outer side of the overlaying and reinforcing area (6) and two end grouting weak areas (7) positioned at the front side and the rear side of the overlaying and reinforcing area (6), wherein the overlaying and reinforcing area (6) is an area where grouting areas of two sleeve valve pipe grouting structures are overlapped;
The two end grouting weak areas (7) are respectively positioned above the front end and the rear end of the overlapped reinforcing area (6), and the advance small guide pipe (8) arranged in the first step is positioned in the end grouting weak areas (7); the two end grouting weak areas (7) are all advanced small conduit grouting reinforcing areas reinforced by adopting advanced small conduits (8), and the overlapping reinforcing areas (6) and the two end grouting weak areas (7) form a core reinforcing area;
the stratum where the constructed connecting channel (2) is located in the core reinforcing area.
2. The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: when preliminary grouting reinforcement is carried out on the stratum at the end part of the channel, stopping grouting when grouting pressure of all the advance small guide pipes (8) in the two groups of the advance small guide pipes (8) reaches P1, and finishing the preliminary grouting reinforcement process of the stratum at the end part of the channel; wherein P1 is a preset preliminary grouting pressure value, and the value range of P1 is 0.7 MPa-0.8 MPa;
stopping grouting when the grouting pressure of all the leading small pipes (8) in the two groups of leading small pipes (8) reaches P2 during the supplementary grouting reinforcement, and completing the supplementary grouting reinforcement process; wherein P2 is a preset supplementary grouting pressure value, and the value range of P2 is 0.5MPa to 0.6MPa.
3. The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel according to claim 1 or 2, wherein the advanced grouting reinforcement method is characterized by comprising the following steps of: the areas where the two shield tunnels (1) are connected with the constructed connecting channel (2) are tunnel connection areas, and each group of the advance small guide pipes (8) are uniformly distributed outside one tunnel connection area; the distance D between the two leading small pipes (8) positioned at the leftmost side and the rightmost side of each group of the leading small pipes (8) is larger than the excavation width of the constructed connecting channel (2);
the number of the advance small pipes (8) included in each group of the advance small pipes (8) is 2M, wherein M is a positive integer and M is more than or equal to 3; the number of the leading small guide pipes (8) positioned at the left side and the right side of the central line of the tunnel of the constructed communication channel (2) in each group of the leading small guide pipes (8) is M;
and in the first step and the third step, grouting is symmetrically performed on the left side and the right side from the middle part respectively when grouting is performed through any group of the advance small guide pipes (8).
4. The advanced grouting reinforcement method for the shield zone communication channel of the water-rich sand layer according to any one of claims 1 to 2, wherein the method comprises the following steps: the advance small guide pipe (8) arranged in the first step is a grouting pipe which is driven into a stratum through a pipe piece lifting hole in a shield pipe piece ring in the shield tunnel (1).
5. The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the tunnel hole of the constructed connecting channel (2) is divided into a lower hole body and an upper hole body positioned above the lower hole body;
each sleeve valve pipe grouting structure comprises a plurality of groups of upper sleeve valve pipes for reinforcing a stratum (5) to be reinforced in the area where the upper hole body is located and a plurality of groups of lower sleeve valve pipes for reinforcing the stratum (5) to be reinforced in the area where the lower hole body is located, wherein the plurality of groups of upper sleeve valve pipes and the plurality of groups of lower sleeve valve pipes are all distributed from inside to outside; each group of upper sleeve valve pipes comprises a plurality of sleeve valve pipes (4) which are distributed along the excavation outline of the upper hole body, and the external inserting angles of the sleeve valve pipes (4) of a plurality of groups of upper sleeve valve pipes are gradually increased from inside to outside; each group of lower sleeve valve pipes comprises a plurality of sleeve valve pipes (4) which are distributed along the excavation outline of the lower hole body, and the external insertion angles of the sleeve valve pipes (4) of a plurality of groups of lower sleeve valve pipes are gradually increased from inside to outside;
in the second step, in the sleeve valve pipe grouting reinforcement process, grouting reinforcement is carried out from outside to inside when sleeve valve pipe grouting reinforcement is carried out through any sleeve valve pipe grouting structure.
6. The advanced grouting reinforcement method for the water-rich sand layer shield zone connecting channel is characterized by comprising the following steps of: the two shield tunnels (1) are connected with the constructed connecting channel (2) in a tunnel connection area, and a plurality of sleeve valve pipe mounting holes for the sleeve valve pipes (4) to be arranged on the shield segment rings of the tunnel connection areas in the two shield tunnels (1).
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| CN109404005B (en) * | 2018-11-09 | 2023-09-15 | 中铁第一勘察设计院集团有限公司 | Pre-reinforcing system for small hole and large hole of underground tunnel and construction method |
| CN209604016U (en) * | 2019-02-18 | 2019-11-08 | 中建八局轨道交通建设有限公司 | Shallow embedding layer of sand tunnel shielding portal end soil body ruggedized construction |
| CN111502696A (en) * | 2020-04-01 | 2020-08-07 | 广州地铁设计研究院股份有限公司 | Dense-mesh type advanced support system of underground excavation tunnel and construction method |
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