CN114704288A - A shock attenuation is from restoring to throne tunnel structure for broken area of fault - Google Patents

Abstract

The invention provides a shock-absorbing self-resetting tunnel structure for a fault fracture zone, which at least comprises a common section and an expanding excavation section corresponding to the fault fracture zone, wherein the expanding excavation section sequentially comprises a primary lining layer, an elastic shock-absorbing layer and a secondary lining layer from outside to inside, the primary lining layer is contacted with surrounding rock, the elastic shock-absorbing layer is filled with elastic shock-absorbing materials, the secondary lining layer is formed by sequentially connecting a plurality of pipe joints, and the pipe joints are fixedly connected through memory alloy springs; the bottoms of the two lining layers are provided with reset frames; and a reset elastic arm is transversely arranged between the two side surfaces of the reset frame and the inner wall of the primary lining layer, and an elastic damping rod for shock absorption and an electric push rod for reset are arranged in the reset elastic arm. This tunnel structure not only has shock attenuation antidetonation function, can reset the tube coupling of dislocation moreover after the macroseism takes place, has reduced the time of salvageing greatly, resumes to pass in the tunnel as early as possible.

Description

A shock-absorbing self-resetting tunnel structure for fault fracture zone

technical field

The invention belongs to the field of tunnel construction, and in particular relates to a tunnel structure which is used in a fault crush zone and has the function of shock absorption and self-reset.

Background technique

The existing tunnel support structure generally includes primary lining and secondary lining. The primary lining is the initial support formed by bolting, hanging nets, shotcrete and other means after the tunnel is excavated. This initial support mainly uses the surrounding rock. The strength forms support; the secondary lining uses reinforced concrete to form a complete reinforced concrete structure inside the primary lining.

When a tunnel passes through a fault or broken zone, the surrounding rock at the fault or broken zone is very broken and has low strength, and is prone to large deformation. When the tunnel crosses the active fault, if there is no corresponding engineering measures to deal with it, the dislocation of the active fault, especially the large displacement dislocation, will cause serious damage to the tunnel structure, seriously threaten the safety of traffic and life and property, and also make rescue and post-disaster repair work difficult. conduct. Therefore, solving the serious threat of large displacement active fault dislocation to the tunnel structure is a major technical problem in tunnel engineering construction.

In terms of seismic resistance and fracture resistance of cross-fault tunnels, the following measures are mainly taken at present: (1) Improve the mechanical properties of tunnel lining materials to improve the seismic performance of the structure, such as using steel fiber reinforced concrete to increase damping, using polymer concrete to Reduce the stiffness, etc.; (2) Set up shock absorption joints, that is, reduce the length of the lining segment, so that the damage is concentrated at the joints when the fault is dislocated, so as to ensure the overall performance of the lining; (3) According to the possible dislocation amount of the fault, expand For the tunnel section size, the porous material is filled between the outer lining and the inner lining, and the effect of fault dislocation is offset by the gap between the outer lining and the inner lining, but the over-excavation size will be limited by economic factors.

To sum up, although some tunnels have adopted measures such as isolation energy dissipation design, articulation design, over-excavation design and other related measures to construct tunnels across active fault zones, due to the relatively simple method, the ability to resist fault dislocation is limited and cannot be To ensure the safe operation of the tunnel under the condition of fault activity, the task of repairing the tunnel after the fault activity is arduous, and it often takes a lot of manpower, material resources and time cost for emergency repair, which affects the normal passage of the tunnel.

SUMMARY OF THE INVENTION

The invention solves the deficiencies in the prior art, and provides a shock-absorbing and self-resetting tunnel structure for a fault fracture zone. The pipe joints are reset, which greatly reduces the time for emergency repairs and restores traffic in the tunnel as soon as possible.

The technical scheme adopted to realize the above-mentioned purpose of the present invention is:

A shock-absorbing and self-resetting tunnel structure for a fault fractured zone, comprising at least a common section and an excavation section corresponding to the fault fractured zone, the expansion and excavation sections sequentially include a primary lining in contact with surrounding rock from outside to inside layer, an elastic shock-absorbing layer filled with elastic shock-absorbing material, and a second lining layer, the second lining layer is formed by connecting a plurality of tube sections in sequence, and the tube sections are connected and fixed by a memory alloy spring;

The bottom of the second lining layer is provided with a reset frame, the top surface of the reset frame is fitted with the outer contour of the second lining layer, the bottom of the reset frame is in contact with the primary lining layer, and the bottom of the reset frame is provided with a rolling unit, Relative movement between the reset frame and the primary lining layer;

A reset elastic arm is arranged laterally between the two sides of the reset frame and the inner wall of the primary lining layer, and the reset elastic arm is provided with an elastic damping rod for shock absorption and an electric push rod for reset, and the bottom end of the reset elastic arm is provided with It is fixed on the inner wall of the primary lining layer, and the top of the reset elastic arm is hinged to the side of the reset frame.

The reset elastic arms are evenly arranged along the traveling direction of the tunnel, and reset elastic arms are correspondingly provided on the left and right sides of the reset frame corresponding to each segment.

The reset elastic arm includes:

The bottom plate, the layer plate and the top plate are arranged parallel to each other, and the middle part of the layer plate is provided with a channel;

The hinge seat installed above the top plate for connecting the reset frame;

A plurality of damping rods arranged between the top plate and the layer plate, the top of the damping rod is fixed to the top plate, the bottom of the damping rod is fixed to the layer plate, and the spacing between the top plate and the layer plate is elastically variable;

The connecting rod is connected between the bottom plate and the layer plate to fix the bottom plate and the layer plate;

The electric push rod is fixed on the bottom plate, and the telescopic rod of the electric push rod protrudes from the channel on the floor plate and can be stretched up and down.

Four damping rods are provided, and the four damping rods are distributed at the four corners of the layer plate and the top plate.

The electric push rod is a worm gear type electric push rod.

The elastic damping layer is filled with elastic rubber rods or poured with elastic concrete.

Mounting holes for installing and fixing memory alloy springs are evenly distributed on the end face of the pipe section, and the mounting holes extend radially inward to the inner wall of the second lining layer; the positions of the mounting holes set on different pipe sections are same.

The reset frame is a steel truss structure, and the rolling unit at the bottom of the reset frame adopts a steel roller, and the steel roller is installed along the traveling direction of the tunnel.

Compared with the prior art, the shock-absorbing and self-resetting tunnel structure for the fault fracture zone provided by the present invention has the following advantages: 1. The present invention firstly carries out expansion and excavation in the fault fracture zone area, and between the primary lining layer and the secondary lining layer; An elastic damping layer is arranged between the two linings, and the elastic damping layer can form protection for the second lining layer, and form an elastic protective layer around the second lining layer, so as to reduce the earthquake damage received by the tunnel. 2. When a large-scale earthquake occurs, irreversible dislocation will occur between the tube sections of the secondary lining. In this application, memory alloy springs are arranged between the tube sections and the tube sections, and the elastic connection of the memory alloy springs is as possible as possible. to reduce the degree of misalignment between pipe sections. 3. After the earthquake occurs, after the irreversible dislocation occurs between the pipe sections, the reset frame and the reset elastic arm set in this application can promote the reset of the pipe sections as much as possible, which greatly reduces the time for emergency repairs and restores the tunnel as soon as possible. Internal access. At the same time, since the reset elastic arm is connected to the reset frame and does not directly contact the pipe section, it can be avoided that the reset elastic arm will burst the secondary lining pipe section when an earthquake occurs.

Description of drawings

Fig. 1 is the overall structural schematic diagram of the shock-absorbing self-resetting tunnel structure for fault fracture zone provided by the present invention;

Figure 2 is a cross-sectional structural diagram of the excavation section;

Fig. 3 is the structural representation of the reset frame;

4 is a schematic structural diagram of a reset elastic arm;

Fig. 5 is the working schematic diagram of the reset elastic arm when it is reset;

6 is a refined finite element model diagram of the shock-absorbing self-resetting tunnel structure provided in the embodiment;

7 is a perspective view of a refined finite element model of the shock-absorbing self-resetting tunnel structure provided in the embodiment;

FIG. 8 is a refined model diagram of the shock-absorbing self-resetting tunnel structure provided in the embodiment (including the primary lining layer, the secondary lining layer and the shock-absorbing layer);

In the picture: 1- Ordinary section, 2- Excavation section, 3- Surrounding rock, 4- Primary lining, 5- Elastic shock absorption layer, 6- Second lining, 7- Mounting hole, 8- Pipe section, 9- Reset frame, 10-rolling unit, 11-reset elastic arm, 12-bottom plate, 13-layer plate, 14-top plate, 15-articulated seat, 16-damping rod, 17-connecting rod, 18-electric push rod, 19- Telescopic rod.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

The present invention provides a shock-absorbing and self-resetting tunnel structure for a fault fractured zone. The overall structure is shown in Figure 1. The two sides of the fault fractured zone are normal mountains, and ordinary tunnel structures can be used here for construction. That is the common section 1 shown in Figure 1; in the area of the fault broken zone, the expansion and excavation are to be carried out, that is, the expansion and excavation section 2. It sequentially includes a primary lining layer 4 in contact with the surrounding rock 3, an elastic shock absorbing layer 5 filled with elastic shock absorbing material, and a secondary lining layer 6. The elastic shock absorbing layer is filled with elastic rubber rods or cast with elastic concrete. The second lining layer is formed by connecting a plurality of tube sections 8 in sequence. The end surfaces of the tube sections are evenly distributed with mounting holes 7 for installing and fixing memory alloy springs, and the mounting holes extend radially inward to the second lining. At the inner wall of the layer; the positions of the installation holes set on different pipe sections are the same, and the pipe sections are connected and fixed by memory alloy springs.

The bottom of the two lining layers is provided with a reset frame 9, and its structure is shown in Figure 3 (the reset frame is assembled from multiple sections in the figure), and the top surface of the reset frame is fitted with the outer contour of the two lining layers, The bottom of the reset frame is in contact with the initial lining layer, and the bottom of the reset frame is provided with a rolling unit 10, and the reset frame and the initial lining layer can move relatively; the reset frame is a steel truss structure, and the rolling unit at the bottom of the reset frame Steel rollers are used, which are installed in the direction of travel of the tunnel.

A reset elastic arm 11 is laterally arranged between the two sides of the reset frame and the inner wall of the primary lining layer. Its structure is shown in Figure 4. The reset elastic arm is provided with an elastic damping rod for shock absorption and an electric power For the push rod, the bottom end of the reset elastic arm is fixed on the inner wall of the primary lining layer, and the top end of the reset elastic arm is hinged to the side surface of the reset frame. The reset elastic arms are evenly arranged along the traveling direction of the tunnel, and reset elastic arms are correspondingly provided on the left and right sides of the reset frame corresponding to each segment. The reset elastic arm includes: a bottom plate 12, a layer plate 13 and a top plate 14 arranged in parallel with each other, the middle of the layer plate is provided with a channel; a hinge seat 15 installed above the top plate for connecting the reset frame; There are four damping rods 16 between the plates, the top of the damping rod is fixed with the top plate, the bottom of the damping rod is fixed with the layer plate, the spacing between the top plate and the layer plate is elastically variable, and the four damping rods are distributed between the layer plate and the top plate. Four corners; connecting rod 17 connected between the bottom plate and the layer plate to fix the bottom plate and the layer plate; the electric push rod 18 fixed on the bottom plate, and the telescopic rod 19 of the electric push rod from the channel on the layer plate Extending out and being able to stretch up and down, the electric push rod is a worm gear type electric push rod, which can obtain a large transmission ratio.

During the construction process, when the tunnel is excavated to the fault fracture zone, the expansion and excavation shall be carried out first. After the expansion and initial lining construction is completed, and the secondary lining of the ordinary section connected with the expansion and excavation section has been completed, the pipeline shall be excavated. For the installation of sections, the pipe sections shall be constructed section by section. Before the first pipe section of the excavation section is installed, place the reset frame first, and the reset frame is placed on the initial lining layer of the excavation section, and then adjust the position of the reset frame, and then install the reset elastic arm. One end of the reset elastic arm is hinged with the side wall of the reset frame, the other end of the reset elastic arm is fixed with the initial lining layer, and the power line interface of the reset elastic arm is drawn out from the gap between the pipe sections. After the reset elastic arm is installed, the first pipe section is installed. The pipe section is transported from outside the tunnel through the tunnel prefabricated arch wall lining block transport and safety integrated machine, and the segments that make up the pipe section are assembled into rings and placed on the reset frame superior. Next, construct the elastic shock-absorbing layer between the pipe section and the primary lining layer, and fill it by filling elastic rubber rods or pouring elastic concrete (a barrier layer is set above the reset frame and the reset elastic arm to connect the two with the elastic shock-absorbing layer. separate layers). Finally, the memory alloy spring is installed. The staff enters the pipe section and inserts the memory alloy spring from the opening at the inner wall to the bottom of the installation hole, and then fixes the end of the memory alloy spring into the installation hole through the pressing block and bolt. At this point, the installation of the first pipe section of the excavation section is completed, and then repeat this step to install the next pipe section.

The working principle of the shock-absorbing self-resetting tunnel structure for the fault fracture zone provided by the present invention is as follows: when a slight earthquake occurs, the fault fracture zone is slightly displaced, and at this time, elastic shock absorption is arranged between the primary lining layer and the secondary lining layer. The elastic shock absorption layer can form protection for the second lining layer, and form an elastic protective layer around the second lining layer, which reduces the earthquake damage to the tunnel, so that the structure of the tunnel is basically not damaged. When a medium-to-large earthquake occurs, the fault fracture zone will have a large displacement, which will lead to a large sway between the two-liner pipe sections. In this application, memory alloy springs are arranged between the pipe sections. Through the elastic connection of the memory alloy spring, the degree of misalignment between the tube sections is reduced as much as possible. At the same time, the displacement of the pipe section will cause the reset frame to be dislocated together with the pipe section, and the damping in the reset elastic arms set on both sides of the reset frame (the telescopic rod of the reset elastic arm is in a retracted state under normal conditions, as shown in Figure 4) The rod can now act as a damper to minimize the shaking experienced by the tube section. After the earthquake, irreversible dislocation occurs between the pipe sections. At this time, according to the degree of lateral dislocation of each pipe section, the electric push rod in the reset elastic arm is controlled to start (if the pipe section is dislocated to the left, it means that the The reset elastic arm is squeezed, and the electric push rod on the left side of the reset frame is activated. Similarly, if it is displaced to the right, the electric push rod on the right side of the reset frame is activated. The large transmission ratio, coupled with the steel roller installed at the bottom of the reset frame along the traveling direction of the tunnel, can gradually reset the pipe section slowly through the slow extension of the telescopic rod in the electric push rod (as shown in Figure 5). In this way, the time for emergency repairs is greatly reduced, and the basic traffic in the tunnel can be restored as soon as possible (to ensure that the life rescue line is opened as soon as possible). If the earthquake damages the power facilities in the tunnel, the external generator can be used to generate electricity during the emergency repair of the tunnel to supply power to the specific reset elastic arm.

The above-mentioned effects of the shock-absorbing self-resetting tunnel structure for the fault fracture zone provided in this embodiment are verified in the following ways:

This application uses ABAQUS finite element software to verify the structure of the shock-absorbing self-resetting tunnel of the fault fracture zone (the model does not include the reset function of the electric push rod), as shown in Figure 6, Figure 7, and Figure 8. The specific modeling details are as follows: The model is divided into three parts: the upper wall, the lower wall and the tunnel structure. The mesh type of the soil, lining and shock absorption layer is 8-node hexahedral linear reduced integration element (C3D8R), and the mesh of the steel skeleton The lattice type is a 2-node truss element (T3D2); the soil adopts the Moore-Coulomb elasto-plastic constitutive, the steel bar and the damping layer adopt the classical plastic constitutive, and the primary lining and the secondary lining adopt the concrete elasto-plastic damage constitutive (Concrete damaged plasticity). ), and the memory alloy springs between the tube sections are simulated by elastic elements.

Small, medium and large earthquake models are used to analyze the dislocation momentum between the tube and tube sections of the tunnel in the fractured zone of the fault layer, and compared with the models without shock absorption layer, memory summation and damping rod. The specific results are shown in the table below. It is found that after adopting the shock-absorbing and self-resetting tunnel structure, the dislocation amount between the tube sections under the same conditions is only 24.5%, 18.7% and 16.5% of those without any shock absorption measures, respectively. , the shock absorption effect is more obvious as the magnitude increases (and the effect without electric push rod reset).

Displacement value between tunnel joints under different working conditions (unit: mm)

small earthquake medium earthquake earthquake Shock-absorbing self-resetting tunnel structure 2.3 4.5 6.2 Without any shock absorption measures 9.4 24.1 37.6

Claims (8)

1. A shock attenuation is from restoring to throne tunnel structure for fault fracture area includes ordinary section and the section of digging that expands that corresponds with fault fracture area at least, its characterized in that: the expanded excavation section sequentially comprises a primary lining layer, an elastic damping layer and a secondary lining layer from outside to inside, wherein the primary lining layer is in contact with surrounding rock, the elastic damping layer is filled with elastic damping materials, the secondary lining layer is formed by sequentially connecting a plurality of pipe joints, and the pipe joints are fixedly connected with the pipe joints through memory alloy springs;

the bottom of the two lining layers is provided with a reset frame, the top surface of the reset frame is attached to the outer contours of the two lining layers, the bottom of the reset frame is in contact with the primary lining layer, the bottom of the reset frame is provided with a rolling unit, and the reset frame and the primary lining layer can move relatively;

the elastic reset arm is transversely arranged between the two side faces of the reset frame and the inner wall of the primary lining layer, an elastic damping rod for shock absorption and an electric push rod for resetting are arranged in the elastic reset arm, the bottom end of the elastic reset arm is fixed on the inner wall of the primary lining layer, and the top end of the elastic reset arm is hinged to the side face of the reset frame.

2. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 1, wherein: the elastic arm that resets evenly sets up along tunnel advancing direction, and the left and right sides that resets that each section of jurisdiction corresponds all corresponds and is provided with the elastic arm that resets.

3. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 2, wherein: the reset spring arm comprises:

the bottom plate, the laminate and the top plate are arranged in parallel, and a channel is arranged in the middle of the laminate;

the hinge seat is arranged above the top plate and is used for connecting the reset frame;

the damping rods are arranged between the top plate and the laminated plate, the tops of the damping rods are fixed with the top plate, the bottoms of the damping rods are fixed with the laminated plate, and the distance between the top plate and the laminated plate is elastically variable;

a connecting rod connected between the bottom plate and the laminate and used for fixing the bottom plate and the laminate;

the electric push rod is fixed on the bottom plate, and the telescopic rod of the electric push rod extends out of the channel on the laminate and can stretch up and down.

4. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 3, wherein: four damping rods are arranged and distributed at four corners of the layer plate and the top plate.

5. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 3, wherein: the electric push rod is a worm and gear type electric push rod.

6. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 1, wherein: and the elastic shock absorption layer is filled with elastic rubber rods or poured with elastic concrete.

7. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 1, wherein: mounting holes for mounting and fixing the memory alloy springs are uniformly distributed on the end surface of the pipe joint, and the mounting holes extend inwards to the inner walls of the two linings along the radial direction; the positions of the mounting holes arranged on different pipe joints are the same.

8. The shock-absorbing self-resetting tunnel structure for a fault-breaking zone of claim 1, wherein: the reset frame is of a steel truss structure, the rolling unit at the bottom of the reset frame is a steel rolling shaft, and the steel rolling shaft is installed along the advancing direction of the tunnel.

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