CN109667598B - Tunnel composite lining design method based on total safety factor method - Google Patents
Tunnel composite lining design method based on total safety factor method Download PDFInfo
- Publication number
- CN109667598B CN109667598B CN201811496389.8A CN201811496389A CN109667598B CN 109667598 B CN109667598 B CN 109667598B CN 201811496389 A CN201811496389 A CN 201811496389A CN 109667598 B CN109667598 B CN 109667598B
- Authority
- CN
- China
- Prior art keywords
- surrounding rock
- secondary lining
- anchor rod
- load
- lining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 63
- 239000011435 rock Substances 0.000 claims abstract description 143
- 239000007921 spray Substances 0.000 claims abstract description 75
- 230000008093 supporting effect Effects 0.000 claims abstract description 74
- 231100000817 safety factor Toxicity 0.000 claims abstract description 55
- 230000006378 damage Effects 0.000 claims abstract description 33
- 238000004364 calculation method Methods 0.000 claims description 46
- 238000010276 construction Methods 0.000 claims description 35
- 230000003993 interaction Effects 0.000 claims description 12
- 239000004570 mortar (masonry) Substances 0.000 claims description 10
- 238000004873 anchoring Methods 0.000 claims description 9
- 230000007423 decrease Effects 0.000 claims description 6
- 238000009792 diffusion process Methods 0.000 claims description 6
- 238000009412 basement excavation Methods 0.000 claims description 5
- 238000003908 quality control method Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 2
- 238000005507 spraying Methods 0.000 description 23
- 229910000831 Steel Inorganic materials 0.000 description 13
- 239000010959 steel Substances 0.000 description 13
- 230000000694 effects Effects 0.000 description 11
- 239000004567 concrete Substances 0.000 description 7
- 230000002787 reinforcement Effects 0.000 description 6
- 239000011378 shotcrete Substances 0.000 description 6
- 238000005457 optimization Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 238000009933 burial Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 201000004569 Blindness Diseases 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- 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
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- 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
- E21D11/003—Linings or provisions thereon, specially adapted for traffic tunnels, e.g. with built-in cleaning devices
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- 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
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Architecture (AREA)
- Structural Engineering (AREA)
- Civil Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
The invention relates to a tunnel composite lining design method based on a total safety factor method, which comprises the steps of determining a surrounding rock pressure representative value of a composite lining; determining the total safety factor of the composite lining according to the support type; preliminarily distributing the determined total safety coefficient of the composite lining to obtain respective safety coefficients of the spray layer, the anchor rod-surrounding rock bearing arch and the secondary lining; determining parameters of a spray layer, an anchor rod and a secondary lining according to distribution results of the safety factors and load structure models corresponding to the distribution results; according to the parameters of the sprayed layer and the secondary lining, a composite structure model is adopted to obtain a load proportion coefficient of the overall damage stage of the composite structure, and the strength matching property between all supporting members can be obtained by comparing the relationship between the load proportion coefficient and the sum of the safety coefficients of the sprayed layer and the secondary lining; and (4) drawing out multiple groups of support parameters according to the total safety factor multi-component matching result, and selecting an optimal support scheme through strength matching, economy and feasibility comparison and comprehensive analysis.
Description
Technical Field
The invention belongs to the field of tunnel engineering, and particularly relates to a tunnel composite lining design method based on a total safety coefficient method.
Background
The composite lining is composed of system anchor rods or anchor cables, sprayed concrete, steel arch frames, a waterproof layer and molded concrete, is a supporting form widely applied to mining, hydraulic caverns and traffic tunnels, mainly depends on engineering analogy and experience value in the design of the traditional composite lining, cannot achieve quantitative design, and brings adverse effects on the safety and economy of engineering.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a design method of a tunnel composite lining, which divides a composite lining support member into an anchor rod-surrounding rock bearing arch, a sprayed concrete layer (comprising sprayed concrete, a reinforcing mesh, a steel arch frame and the like, hereinafter referred to as sprayed layer for short) and a secondary lining three-layer bearing structure, establishes a load structure model (model I) of the sprayed layer, a load structure model (model II) of the anchor rod-surrounding rock bearing arch and a load structure model (model III) of the secondary lining, obtains respective safety coefficients of the three through calculation, and the sum of the safety coefficients of the three is the total safety coefficient of the composite lining, so that the total safety coefficient meets the design requirements of a construction period and an operation period, and finally realizes the optimization design of the support structure through the comparison and selection of the strength matching of the support member, the economical efficiency and the practicability of support parameters, the technical scheme of the invention is as follows:
a tunnel composite lining design method based on a total safety factor method comprises the following steps:
s1, determining a surrounding rock pressure representative value of the composite lining;
s2, determining the value of the total safety factor of the composite lining according to the support type;
s3, preliminarily distributing the total safety coefficient of the composite lining determined in the S2 to obtain a plurality of distribution combinations, wherein each distribution combination comprises a spray layer safety coefficient, an anchor rod-surrounding rock bearing arch safety coefficient and a secondary lining safety coefficient;
s4, calculating spray layer parameters corresponding to each group of distribution combination by adopting a load structure model of the spray layer according to the spray layer safety coefficient in each group of distribution combination, wherein the spray layer parameters comprise the strength grade, the thickness, the steel arch frame parameters and the like of the spray layer;
s5, calculating secondary lining parameters corresponding to each group of distribution combination by adopting a load structure model of secondary lining according to the secondary lining safety coefficient in each group of distribution combination, wherein the secondary lining parameters comprise the concrete grade, the thickness, the reinforcement parameters and the like of the secondary lining;
s6, calculating anchor rod parameters corresponding to each group of distribution combination by adopting an anchor rod-surrounding rock bearing arch load structure model according to the safety factors of the spray layer, the secondary lining and the anchor rod-surrounding rock bearing arch in each group of distribution combination, wherein the anchor rod parameters comprise the length, the diameter, the material, the distance between adjacent anchor rods and the like;
s7, calculating the load proportion coefficient of the overall damage stage of the composite structure corresponding to each group of distribution combination, the damage sequence of the sprayed layer and the secondary lining and the corresponding damage load by adopting a composite structure model according to the sprayed layer parameters and the secondary lining parameters calculated in each group of distribution combination;
and S8, performing strength matching, economical efficiency and implementability ratio selection and comprehensive analysis on the supporting member according to the sprayed layer safety coefficient, the anchor rod-surrounding rock bearing arch safety coefficient and the secondary lining safety coefficient in each group of distribution groups and the sprayed layer parameter, the secondary lining parameter, the anchor rod parameter and the load proportion coefficient calculated by each group of distribution groups to obtain a more economical and reasonable supporting scheme.
Further, the S1 specifically includes:
when the buried depth H is more than or equal to 10-15 times of the hole diameter D, the calculation formula of the surrounding rock pressure representative value is as follows:
the vertical uniform load is that q is α gamma (R)pd-a)；
Horizontally and uniformly distributing load, wherein e is β lambda q;
wherein the content of the first and second substances,
wherein gamma is the weight of the surrounding rock, lambda is the lateral pressure coefficient of the surrounding rock, α and β are the pressure adjusting coefficients of the surrounding rock at the arch part and the lateral part respectively, which are generally not less than 1.2, and are adjusted according to the factors of the occurrence of the surrounding rock and the like (for example, the horizontal rock stratum, α can be a coefficient more than 1.0, β can be a coefficient less than 1.0), and PiFor the supporting force, time P is calculatedi＝0；RpdIs the radius of the tunnel plastic zone; p0Initial stress of surrounding rock; c is the cohesive force of the surrounding rock;
the internal friction angle of the surrounding rock; theta is an included angle with the transverse shaft of the tunnel, and the included angle is 45 degrees during calculation; r0Taking the equivalent circle radius when the section is non-circular; a is the distance from the center of the equivalent circle to the tunnel excavation boundary at the position of 45 degrees;
when the time is 2.5hq<H<(10-15) D;
wherein h isq＝0.45×2S-1ω；
Wherein S is the grade of surrounding rock; ω is the width influence coefficient, ω 1+ i (B-5); b is the width (m) of the tunnel; i is the surrounding rock pressure increase and decrease rate when the B increases and decreases by 1m, and when the B is less than 5m, i is 0.2; when B is more than 5m, i is 0.1;
solving the plastic zone range without support by adopting an elastic-plastic finite element method under actual buried depth, taking the average plastic zone height within 90-degree range of an arch part as the equivalent height of a surrounding rock pressure representative value, and directly adopting a formula calculated value when H is (10-15) D for ensuring safety;
when H is present<2.5hqWhen the current is over;
calculating by adopting a shallow-buried surrounding rock pressure formula E.0.2-1-E.0.2-1 in appendix E of Tunnel design Specification TB 10003-2016;
the surrounding rock pressure representative value of the weak surrounding rock needs to consider the space effect (the clamping effect of the good surrounding rock on two sides) and the reduction effect of the advanced grouting reinforcement ring on the surrounding rock pressure.
Further, the value of the total safety factor in S2 should satisfy:
total safety factor K in operation phaseop≥3.0～3.6；
Total safety factor K in the construction phasec≥1.8～2.1；
The total safety coefficient can be adjusted according to the structural importance, the specific conditions of surrounding rocks and construction quality control factors;
wherein, no secondary lining is adopted in the construction stage, and the total safety factor is formed by the sum of the safety factors of the spray layer and the anchor rod-surrounding rock bearing arch.
Further, the distribution principle and the distribution of the total safety factor preliminary distribution of the composite lining in S3
The preparation method adopts the following formula to calculate:
and (3) construction stage: kc＝K1+K2；
And (3) an operation stage:
when adopting durability stock: kop＝K1+K2+K3；
When a non-durable anchor rod is adopted: kop＝K1+K3；
Wherein, K1、K2、K3Safety factors of a spray layer, an anchor-enclosure bearing arch and a secondary lining are respectively set;
wherein, no secondary lining is adopted in the construction stage, and the total safety coefficient is formed by the sum of the safety coefficients of the spray layer and the anchor rod-surrounding rock bearing arch; in the operation stage, the total safety coefficient when the durable anchor rod is adopted consists of the sum of the safety coefficients of the spray layer, the anchor rod-surrounding rock bearing arch and the secondary lining, and the total safety coefficient when the non-durable anchor rod is adopted consists of the sum of the safety coefficients of the spray layer and the secondary lining.
Further, the determination of the load structure model of the spray layer in S4 and the calculation method of the spray layer parameters in each group of distribution combination are as follows:
the load structure model of the spraying layer is a calculation model based on finite elements, the spraying layer is simulated by adopting a beam unit, the interaction between the structure and the stratum is simulated by adopting a non-pulling radial spring and a tangential spring, the rigidity of the tangential spring can be generally about 1/3, the load adopts the surrounding rock pressure representative value in the step S1, after the internal force of the spraying layer is obtained, the spraying layer parameters and the safety coefficient are calculated by adopting a damage stage method according to the current railway tunnel design specification TB10003-2016, when a steel frame and a steel bar net are arranged in the spraying layer, the minimum thickness of the spraying layer as a structural layer is not smaller than 8cm, and the spraying layer parameters are not counted when the thickness is smaller than 8 cm.
Further, the determination of the load structure model of the secondary lining in S5 and the calculation method of the secondary lining parameters in each group of distribution combination are as follows:
the load structure model of the secondary lining is a calculation model based on finite elements, the secondary lining is simulated by adopting a beam unit, the area where the waterproof board is laid on the arch wall is simulated by adopting a tension-free radial spring, the contact between the inverted arch area and the primary support is simulated by adopting a tension-free radial spring and a tangential spring, the rigidity of the tangential spring can be about 1/3 of the tension-free radial spring generally, and the load adopts the surrounding rock pressure representative value in the step S1; after the internal force of the secondary lining is obtained, secondary lining parameters and safety coefficients are calculated by adopting a damage stage method according to the current railway tunnel design specification TB 10003-2016.
Further, the determination of the load structure model of the anchor rod-surrounding rock bearing arch in S6 and the calculation method of the anchor rod parameters in each group of distribution combination are as follows:
s61: pressure diffusion is carried out on the outer end of each anchor rod towards the inner side of the tunnel according to a certain angle (the angle is selected from 30-45 degrees according to physical and mechanical indexes of surrounding rocks, the surrounding rocks with high strength have large values), a connecting line formed by intersection points of adjacent anchor rods after pressure diffusion is an outer edge line of the bearing arch, the inner edge line of the bearing arch is the outer surface of a spraying layer, a beam unit is adopted to simulate an anchor rod-surrounding rock bearing arch, a tension-free radial spring is adopted to simulate the interaction between the surrounding rocks and the bearing arch, elastic support is adopted at the arch foot, and the load adopts the surrounding rock pressure representative value in the step S1;
s62: and after the internal force of the bearing arch is obtained, calculating anchor rod parameters and the anchor rod-surrounding rock bearing arch safety coefficient according to tunnel design specification TB 10003-2016. Wherein, the ultimate strength of the surrounding rock in the anchor rod-surrounding rock bearing arch range only considers the strength increased after supporting, and the calculation formula is as follows:
wherein: [ sigma ]c]For bearing the ultimate strength, σ, of the surrounding rock within the arch3The supporting force is provided for the spray layer and the anchor rod;
supporting force sigma provided by anchor rods32The calculation formula is as follows:
σ32＝min[fyπd2/(4bs·ks),frbπdglg/(bs·kg)]。
wherein σ32The supporting force provided for the anchor rod; k is a radical ofsThe yield bearing capacity safety factor of the anchor rod is not less than 2.0; k is a radical ofgThe anti-pulling safety coefficient of the anchor rod is not less than 2.5; f. ofyThe yield strength of the anchor bar steel; d is the anchor bar diameter; f. ofrbThe ultimate bonding strength between the mortar anchoring body and the ground layer; dgThe outer diameter of the mortar anchoring body; lgThe anchoring length of the anchor bar and the mortar; b. s is the circumferential spacing and the longitudinal spacing of the anchor rods respectively;
supporting force sigma provided by the sprayed layer31Supporting force sigma provided by secondary lining31Is calculated asThe following:
σ31＝0.5K1·q；
σ33＝0.5K3·q；
wherein, K1、K3Safety factors of a sprayed layer and a secondary lining are respectively set;
when the thickness of the sprayed layer is less than 8cm, the sprayed layer provides sigma31Can be ignored;
the total supporting force provided by the anchor rod, the sprayed layer and the secondary lining is taken as sigma3The values are different in the construction period and the operation period, and sigma can be adopted3cAnd σ3opThe supporting force provided by the supporting system for the anchor rod-surrounding rock bearing arch in the construction period and the operation period respectively has the following calculation formula:
σ3c＝σ31+σ32；
σ3op＝σ31+σ32+σ33；
s63: when the thickness of the sprayed layer of the tunnel is less than 8cm, the supporting effect of the sprayed layer is ignored, the anchor rod needs to meet the requirement of the minimum supporting force besides the requirement of all supporting forces required by the anchor rod-surrounding rock bearing arch in the S62, and the calculation formula is as follows:
min[fyπd2/(4bs·ks),frbπdglg/(bs·kg)]＞Pimin；
further, the determination of the composite structure model in S7 and the calculation method of the load proportionality coefficient of the corresponding overall failure stage are as follows:
s71: the composite structure model is a calculation model based on finite elements, the spray layer and the secondary lining are simulated by adopting beam units, the interaction between the spray layer and the stratum is simulated by adopting non-pull radial springs and tangential springs, and the rigidity of the non-pull radial springs and the rigidity of the tangential springs are consistent with that of the non-pull radial springs and the tangential springs in the load structure model of the spray layer in the step S4; the interaction between the sprayed layer and the secondary lining is simulated by using a non-pulling radial spring between the sprayed layer and the secondary lining, and the rigidity k of the non-pulling radial spring between the sprayed layer and the secondary lining can be expressed as follows:
wherein E is1、E2The elastic modulus h of the sprayed layer and the secondary lining respectively1、h2The thicknesses of the sprayed layer and the secondary lining are respectively, and A is the area of the contact unit;
wherein, the tangential spring stiffness of the secondary lining inverted arch area is consistent with that of the spray layer tangential spring.
S72: and (4) adopting the composite structure model of S71 to gradually increase the load, wherein a certain section reaches the damage stage, assuming that the section can maintain the bearing capacity of the damage stage, applying the internal force of the damage region as a boundary condition to the damage position, and then continuously increasing the load until the whole structure is damaged, wherein the load at the moment is taken as a limit load, and the ratio of the limit load to the design load is the load proportionality coefficient of the whole damage stage of the composite lining.
Further, the S8 specifically includes:
dividing the load proportion coefficient in each group of distribution combination by the sum of the safety factors of the sprayed layer and the secondary lining to serve as an index for judging the strength matching of the supporting member, wherein the ratio is always greater than 1, and the matching is better when the ratio is close to 1;
wherein the economic indicators of the supporting member comprise: the economic factors such as the excavation amount, the amount of each supporting member, the personnel mechanical configuration required by each supporting measure, the supporting cycle period and the like; the implementability indexes of the supporting member include: each supporting member cannot exceed the existing construction level and cannot influence the operation conditions of other supporting members.
The invention has the beneficial effects that:
according to the design method of the tunnel composite lining based on the safety coefficient method, provided by the invention, the safety coefficient of a composite lining support system can be calculated, so that the bearing capacity of the composite lining can be quantitatively analyzed, powerful means can be provided for support member selection, quantitative design and integral optimization design of the composite lining, and the blindness and the randomness of the traditional design method are avoided; in addition, the calculation model, the acquisition of the calculation parameters and the solving process of the safety coefficient in the tunnel composite lining design method provided by the invention are simple and easy to operate, can be quickly mastered by engineering technicians, and are convenient to popularize and use.
Drawings
FIG. 1 is a schematic flow chart of a tunnel composite lining design method based on a total safety factor method according to an embodiment of the present invention;
FIG. 2 is a schematic view of a load structure model of a sprayed layer in the tunnel composite lining design method based on the total safety factor method, namely a model I;
fig. 3 is a schematic view of a load structure model of an anchor rod-surrounding rock bearing arch in the tunnel composite lining design method based on the total safety coefficient method, namely a model two, provided by the embodiment of the invention;
fig. 4 is a schematic view of a load structure model of a secondary lining in the tunnel composite lining design method based on the total safety factor method, namely a model three, provided by the embodiment of the invention;
fig. 5 is a schematic view of a load structure model of a composite structure in the tunnel composite lining design method based on the total safety factor method according to the embodiment of the present invention.
Description of reference numerals: 1. spraying a layer; 2. a tension-free radial spring; 3. a tangential spring; 4. secondary lining; 5. anchor-surrounding rock bearing arches; 6. an anchor rod; 7. no radial spring is pulled between the sprayed layer and the secondary lining.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention can provide powerful means for the selection, quantitative design and integral optimization design of the supporting member of the composite lining, and the parameters to be designed and confirmed in the composite lining are as follows: (1) spraying a layer 1: the method comprises the following steps of (1) including the thickness of sprayed concrete, the strength grade of the sprayed concrete and the parameters of a steel arch frame; (2) anchor rod 6: the length, the interval, the diameter and the material of the anchor rod are included; (3) and the secondary lining 4 comprises the thickness of the secondary lining, the concrete strength grade and the reinforcement parameters.
The design flow chart of the composite lining design method based on the safety coefficient method is shown in figure 1, spray layer parameters, anchor rod parameters and secondary lining parameters can be determined in sequence, optimal design is achieved by selecting the implementability and the economical ratio and checking the strength matching relationship of the spray layer and the secondary lining, and the specific design steps and the parameter determination process are as follows:
s1, determining a surrounding rock pressure representative value of the composite lining; the method is divided into three cases according to the buried depth of the tunnel: (1) deeply burying; (2) medium burial depth; (3) shallow burying, different burying depth grades correspond to different calculation formulas, and the specific calculation is as follows:
when the buried depth H is larger than or equal to 10-15 times of the hole diameter D, the buried depth is deep, and a calculation formula of a surrounding rock pressure representative value is as follows:
the vertical uniform load is that q is α gamma (R)pd-a)； (1)
Horizontal uniform load, e is β lambdaq (2)
Wherein
Wherein gamma is the weight of the surrounding rock, lambda is the lateral pressure coefficient of the surrounding rock, α and β are respectively the pressure adjusting coefficients of the arch and the lateral surrounding rock, which are generally not less than 1.2, and are adjusted according to the conditions of the surrounding rock (such as horizontal rock, α is more than 1.0, β is less than 1.0)Coefficients); piFor the supporting force, P is taken in calculationi＝0；RpdThe radius of the tunnel plastic zone; p0Initial stress of surrounding rock; c is the cohesive force of the surrounding rock;
the internal friction angle of the surrounding rock; theta is an included angle with the transverse shaft of the tunnel, and is taken as 45 degrees; r0Taking the equivalent circle radius when the section is non-circular; a is the distance from the center of the equivalent circle to the tunnel excavation boundary at the position of 45 degrees;
when the time is 2.5hq<H<(10-15) D, burying the substrate in medium depth;
wherein h isq＝0.45×2S-1ω； (4)
Wherein S is the grade of surrounding rock; ω is the width influence coefficient, ω 1+ i (B-5); b is the width (m) of the tunnel; i is the surrounding rock pressure increase and decrease rate when the B increases and decreases by 1m, and when the B is less than 5m, i is 0.2; when B is more than 5m, i is 0.1;
solving the plastic zone range without support by adopting an elastic-plastic finite element method under actual buried depth, taking the average plastic zone height within 90-degree range of an arch part as the equivalent height of a surrounding rock pressure representative value, and directly adopting a formula calculated value when H is (10-15) D for ensuring safety;
when H is present<2.5hqWhen in use, the shallow buried layer is formed;
calculating by adopting a shallow buried surrounding rock pressure formula E.0.2-1-E.0.2-1 in appendix E of railway tunnel design specification TB 10003-2016;
the surrounding rock pressure representative value of the weak surrounding rock needs to consider the space effect (the clamping effect of the surrounding rocks on two sides is good) and the reduction effect of the advanced grouting reinforcement ring on the surrounding rock pressure, the weak surrounding rock in the short section, namely the surrounding rocks on two sides, is high in grade, the clamping effect on the weak surrounding rock can be achieved, and the influence of the space effect needs to be considered in the surrounding rock pressure representative value. The long section deep-buried weak surrounding rock generally needs to be reinforced in advance, and the surrounding rock pressure needs to consider the reduction effect of the advanced grouting reinforcement ring on the surrounding rock pressure.
S2, determining the value of the total safety factor of the composite lining according to the support type, wherein the value is suggested as follows:
total safety factor K in operation phaseop≥3.0～3.6；
Total safety factor K in the construction phasec≥1.8～2.1；
The total safety coefficient can be adjusted according to the structural importance, the specific conditions of surrounding rocks and construction quality control factors;
wherein, no secondary lining 4 is arranged in the construction stage, and the total safety factor is formed by the sum of the safety factors of the spray layer 1 and the anchor rod-surrounding rock bearing arch 5.
S3, preliminarily distributing the total safety coefficient of the composite lining determined in the S2 to obtain a plurality of distribution combinations, wherein each distribution combination comprises a spray layer safety coefficient, an anchor rod-surrounding rock bearing arch safety coefficient and a secondary lining safety coefficient, and the distribution principle and the distribution method of the total safety coefficient of the composite lining can be calculated by adopting the following formula:
and (3) construction stage: kc＝K1+K2； (5)
And (3) an operation stage:
when adopting durability stock: kop＝K1+K2+K3； (6)
When a non-durable anchor rod is adopted: kop＝K1+K3； (7)
Wherein, K1、K2、K3Safety factors of the spray layer 1, the anchor rod-surrounding rock bearing arch 5 and the secondary lining 4 are respectively set;
wherein, no secondary lining 4 is arranged in the construction stage, and the total safety coefficient is formed by the sum of the safety coefficients of the spray layer 1 and the anchor rod-surrounding rock bearing arch 5; in the operation stage, the total safety coefficient when the durable anchor rod is adopted consists of the sum of the safety coefficients of the spray layer 1, the anchor rod-surrounding rock bearing arch 5 and the secondary lining 4, and the total safety coefficient when the non-durable anchor rod is adopted consists of the sum of the safety coefficients of the spray layer 1 and the secondary lining 4.
In the above embodiment, it is first distinguished whether the anchor rod 6 is a durable anchor rod, if not, the total safety factor will not be taken into account for the action of the anchor rod-surrounding rock bearing arch in the operation stage, and when the safety factors are distributed, the safety factors of the spray layer 1 and the anchor rod-surrounding rock bearing arch 5 should meet the safety requirement of the construction period in S3. For example: the total safety coefficient is 3.6, the spraying layer safety coefficient can be primarily distributed to be 1.5, the anchor rod-surrounding rock bearing arch safety coefficient is 0.5, and the secondary lining safety coefficient is 1.6; and the safety coefficient of a sprayed layer can be preliminarily distributed to be 1.3, the safety coefficient of the anchor rod-surrounding rock bearing arch is 1.3, the safety coefficient of the secondary lining anchor rod-surrounding rock bearing arch is 1.0 and the like.
S4, calculating spray layer parameters corresponding to each group of distribution combination by adopting a load structure model of the spray layer according to the spray layer safety coefficient in each group of distribution combination, wherein the spray layer parameters comprise the strength grade, the thickness, the steel arch frame parameters and the like of the spray layer;
the method for determining the load structure model of the sprayed layer and calculating the parameters of the sprayed layer comprises the following steps:
the load structure model of the spraying layer is a calculation model based on finite elements, the spraying layer 1 is simulated by a beam unit, the interaction between the structure and the stratum is simulated by a non-pulling radial spring 2 and a tangential spring 3, the rigidity of the tangential spring 3 can be about 1/3 of the rigidity of the non-pulling radial spring 2 generally, the load is a surrounding rock pressure representative value, after the internal force of the spraying layer 1 is obtained, the spraying layer parameters and the safety coefficient are calculated by adopting a damage stage method according to the existing railway tunnel design specification TB10003-2016, when a steel frame and a steel bar net are arranged in the spraying layer 1, the minimum thickness of the spraying layer 1 as a structural layer is not smaller than 8cm according to calculation according to a reinforced concrete or a section steel-concrete combined structure, the safety coefficient is not considered as 0 at the moment.
S5, calculating secondary lining 4 parameters corresponding to each group of distribution combination by adopting a load structure model of the secondary lining 4 according to the secondary lining safety coefficient in each group of distribution combination, wherein the secondary lining 4 parameters comprise concrete grade, thickness, reinforcement parameters and the like of the secondary lining 4;
the method for determining the load structure model of the secondary lining and calculating the secondary lining parameters comprises the following steps:
the load structure model of the secondary lining is a calculation model based on finite elements, as shown in figure 4, the secondary lining 4 is simulated by adopting a beam unit, a waterproof plate laying area of an arch wall is simulated by adopting a tension-free radial spring 2, an inverted arch area is contacted with a primary support and is simulated by adopting a tension-free radial spring 2 and a tangential spring 3, the rigidity of the tangential spring 3 can be about 1/3 of that of the tension-free radial spring 2 generally, and the load is represented by the surrounding rock pressure; after the internal force of the secondary lining 4 is obtained, secondary lining parameters and safety coefficients are calculated by adopting a damage stage method according to the current railway tunnel design specification TB 10003-2016.
And S6, calculating anchor rod parameters corresponding to each group of distribution combination by adopting a load structure model of the anchor rod-surrounding rock bearing arch according to the safety factors of the spray layer, the secondary lining and the anchor rod-surrounding rock bearing arch in each group of distribution combination, wherein the anchor rod parameters comprise the length, the diameter, the material, the distance between adjacent anchor rods 6 and the like.
The method for determining the load structure model of the anchor rod-surrounding rock bearing arch and calculating the anchor rod parameters comprises the following steps:
s61: as shown in fig. 3, the outer end of the anchor rod 6 is subjected to pressure diffusion towards the inner side of the tunnel according to a certain angle (the angle is selected from 30-45 degrees according to the physical and mechanical indexes of the surrounding rock, and the surrounding rock with high strength is large), a connecting line formed by intersection points of adjacent anchor rods 6 after pressure diffusion is an outer edge line of the bearing arch, the inner edge line of the bearing arch is the outer surface of the spraying layer 1, the bearing arch is simulated by adopting a beam unit, the interaction between the surrounding rock and the bearing arch is simulated by adopting a non-tension radial spring 2, and the arch foot is elastically supported;
s62: after the internal force of the bearing arch is obtained, anchor rod parameters and a safety factor are calculated according to railway tunnel design specification TB10003-2016, wherein the ultimate strength of the surrounding rock in the range of the anchor rod-surrounding rock bearing arch 5 only considers the strength increased after supporting, and the calculation formula is as follows:
wherein: [ sigma ]c]For bearing the ultimate strength, σ, of the surrounding rock within the arch3The supporting force is provided for the spray layer 1 and the anchor rod 6;
the supporting force σ provided by the anchor rods 632The calculation formula is as follows:
σ32＝min[fyπd2/(4bs·ks),frbπdglg/(bs·kg)]。 (9)
wherein σ32The supporting force provided for the anchor 6; k is a radical ofsThe yield bearing capacity safety factor of the anchor rod 6 is not less than 2.0; kg is the anti-pulling safety coefficient of the anchor rod 6 and is not less than 2.5; f. ofyThe yield strength of the anchor bar steel; d is the anchor bar diameter; f. ofrbThe ultimate bonding strength between the mortar anchoring body and the ground layer; dgThe outer diameter of the mortar anchoring body; lgThe anchoring length of the anchor bar and the mortar; b. s is the circumferential spacing and the longitudinal spacing of the anchor rods 6 respectively;
supporting force sigma provided by the sprayed layer 131The supporting force sigma being provided by the secondary lining 431The calculation formula of (a) is as follows:
σ31＝0.5K1·q； (10)
σ33＝0.5K3·q； (11)
wherein, K1、K3Safety factors of a sprayed layer and a secondary lining are respectively set;
when the thickness of the sprayed layer 1 is less than 8cm, the sprayed layer 1 provides sigma31Can be ignored;
the total supporting force provided by the anchor rod 6, the spray layer 1 and the secondary lining 4 is taken as sigma3The values are different in the construction period and the operation period, and sigma can be adopted3cAnd σ3opThe supporting force provided by the supporting system for the anchor rod-surrounding rock bearing arch in the construction period and the operation period respectively has the following calculation formula:
σ3c＝σ31+σ32； (12)
σ3op＝σ31+σ32+σ33； (13)
s63: when the thickness of the tunnel spray layer 1 is less than 8cm, the support effect of the spray layer 1 is ignored, the anchor rod 6 needs to meet the requirement of the minimum support force besides the requirement of all the support forces required by the anchor rod-surrounding rock bearing arch in the S62, and the calculation formula is as follows:
min[fyπd2/(4bs·ks),frbπdglg/(bs·kg)]＞Pimin； (14)
s7, calculating the load proportion coefficient of the overall damage stage of the composite structure corresponding to each group of distribution combination, the damage sequence of the spray layer 1 and the secondary lining 4 and the corresponding damage load by adopting a composite structure model according to the parameters of the spray layer 1 and the secondary lining 4 calculated in each group of distribution combination;
the method for determining the composite structure model and calculating the load proportion coefficient of the corresponding overall failure stage comprises the following steps:
s71: the composite structure model is a finite element-based calculation model, as shown in fig. 5, the spray layer 1 and the secondary lining 4 are both simulated by using beam units, the interaction between the spray layer 1 and the ground is simulated by using the tension-free radial springs 2 and the tangential springs 3, and the rigidity of the tension-free radial springs 2 and the rigidity of the tangential springs 3 are consistent with that of the tension-free radial springs 2 and the tangential springs 3 in the load structure model of the spray layer 1 in the step S4; the interaction between the sprayed layer 1 and the secondary lining 4 is simulated by using the radial spring 7 without tension between the sprayed layer and the secondary lining, and the rigidity k of the radial spring 7 without tension between the sprayed layer and the secondary lining can be expressed as:
wherein E is1、E2The elastic modulus h of the sprayed layer 1 and the secondary lining 4 respectively1、h2The thicknesses of the spray layer 1 and the secondary lining 4 are respectively, and A is the area of the contact unit;
wherein, the rigidity of the tangential spring 3 of the inverted arch area of the secondary lining 4 is consistent with that of the tangential spring 3 of the spray layer 1;
s72: using the composite structure model described in S71, gradually increasingA large load, wherein a certain cross section reaches a breakage stage, assuming that the cross section can maintain the bearing capacity of the breakage stage, and applying the internal force (bending moment and axial force) of the breakage region as a boundary condition to the breakage position, as shown in fig. 5(b) and (c) corresponding to two conditions of large eccentric compression failure and small eccentric compression failure, respectively, wherein M is a structural bending moment; and N is structural axial force. And then continuing to increase the load until the structure is integrally destroyed, taking the load at the moment as a limit load, taking the ratio of the limit load to the design load as a load proportion coefficient of the overall destruction stage of the composite lining, simultaneously recording the destruction sequence of the spray layer 1 and the secondary lining 4 and the corresponding destruction load, respectively calling the members which successively reach the worst cross section as a first member and a second member, and calling the loads during destruction as a critical destruction load and a limit load. Because the anchor rod-surrounding rock bearing arch is positioned at the outermost layer, as long as the spray layer 1 and the secondary lining 4 are not damaged, sigma can be continuously provided for the anchor rod-surrounding rock bearing arch3Therefore, the situation that the anchor rod-surrounding rock bearing arch is firstly damaged in the spraying layer 1 and secondarily cannot occur, and according to the requirements of the unified design standard for reliability of engineering structure (GB50153-2008) on the safety and the applicability of the structure, the invention considers that if one section of the spraying layer 1 and the secondary lining 4 reaches a damaged state or at least three sections of the secondary lining 4 reach the damaged state, the composite lining structure reaches the limit load.
S8, carrying out strength matching, economical efficiency and implementability ratio selection and comprehensive analysis on the supporting members according to the spraying layer 1 safety coefficient, the anchor rod-surrounding rock bearing arch 5 safety coefficient and the secondary lining 4 safety coefficient in each group of distribution groups and the spraying layer 1 parameter, the secondary lining 4 parameter, the anchor rod 6 parameter and the load proportion coefficient calculated by each group of distribution groups to obtain a more economical and reasonable supporting scheme;
the strength matching performance of the supporting member is specifically as follows: dividing the load proportion coefficient in each group of distribution combination by the sum of the safety factors of the sprayed layer and the secondary lining to serve as an index for judging the strength matching of the supporting member, wherein the ratio is always greater than 1, and the matching is better when the ratio is close to 1;
the strength matching of the supporting member is compared with the economic indexes of each parameter combination, the feasibility of each supporting parameter is comprehensively analyzed, and reasonable supporting parameters are finally obtained;
the economic indexes of the supporting member comprise: excavating amount, the amount of each supporting member, personnel mechanical configuration required by each supporting measure, supporting cycle period and the like;
the implementability indexes of the supporting member include: each supporting member cannot exceed the existing construction level, and cannot affect the construction conditions of other supporting members.
In order to more accurately illustrate the practicability of the invention and facilitate the understanding of the wide engineering technicians, the calculation results of the durable anchor rod and the non-durable anchor rod are adopted and compared with a general reference diagram by taking the burial depth of 400m of the IV-grade surrounding rock of the double-track tunnel of the high-speed railway with the speed of 350km per hour as a case, and the specific steps are as follows:
1) and determining a surrounding rock pressure representative value of the composite lining.
The physical and mechanical indexes of the surrounding rock parameters are the lower one third of the range value of railway tunnel design specification TB10003-2016, the equivalent circle radius of the double-track tunnel of the high-speed railway with the speed per hour of 350km is 7.5m, q is 227kPa according to the formulas (1) to (3), and the lateral pressure coefficient is 0.5.
2) Determining the value range of the total safety coefficient of the composite lining according to the support type;
total safety factor K in operation phaseopNot less than 3.0-3.6, and the total safety coefficient K of the spray layer 1 and the anchor rod-surrounding rock bearing arch 5 in the construction stage (without the secondary lining 4)cNot less than 1.8 to 2.1, in this case K is takenop≥3.6，Kc≥2.1。
3) For comparison and explanation, firstly, the safety coefficient calculation is carried out on general reference diagram parameters of '350 km/h passenger special line double-track railway tunnel composite lining', the calculation result is shown in table 1, wherein the safety coefficient of a spray layer 1 is 2.96, the safety coefficient of an anchor rock bearing arch in the safety coefficient construction period is 2.64, the safety coefficient of an operation period is 4.53, the safety coefficient of a secondary lining is 5.08, the total safety coefficient is higher, even if anchor rods 6 are omitted in part of work points, the safety of the construction period and the operation period cannot be greatly influenced, and the support parameters have larger optimization space.
4) During design, the determined total safety factor of the composite lining is primarily distributed to obtain respective safety factors of a spray layer, an anchor rod-surrounding rock bearing arch and a secondary lining, and two schemes are adopted for distribution:
scheme one, adopt durability stock 6: the safety coefficient of the spray layer 1 is 1.5, the safety coefficient of the anchor rod-surrounding rock bearing arch in the construction period is 1.0, and the safety coefficient of the secondary lining 4 is 1.2;
scheme two, adopt non-durability stock 6: the safety coefficient of the spray layer 1 is 2.5, the safety coefficient of the anchor rod-surrounding rock bearing arch in the construction period is 0.5, and the safety coefficient of the secondary lining 4 is 1.2.
When the non-durable anchor rod 6 is adopted, the safety coefficient of the anchor rod-surrounding rock bearing arch cannot be taken into account of the total safety coefficient in the operation period, and only the safety requirement in the construction period is met.
5) The parameters of the spray layer 1, the anchor rod 6 and the secondary lining 4 can be respectively determined according to the model I, the model II and the model III in the steps S4, S5 and S6, the calculation result is shown in Table 1, and it needs to be explained that in order to meet the pouring requirement of concrete, the thickness of the secondary lining 4 is generally not less than 30cm, 30cm is uniformly taken in the present case, and the safety coefficient of the secondary lining of 30cm is 2.83 which is higher than 1.2 of the distribution.
It should be noted that, when the parameters are drawn up by the assigned safety factors, the safety factors of the obtained parameters need only be substantially equal to the assigned safety factors, and need not be completely consistent.
6) Establishing the S7 composite structure model, calculating to obtain that the first support member damaged in the first scheme is the sprayed layer 1, the critical damage load is 800kPa, the second support member is the secondary lining 4, the limit load is 1100kPa, the load proportion coefficient is 4.84, the sum of the safety coefficients of the sprayed layer 1 and the secondary lining 4 determined in the steps S4 and S5 is 12% higher than the sum of the safety coefficients of the sprayed layer 1 and the secondary lining 4, and the matching relation is reasonable;
and in the second scheme, the first supporting member of the second scheme is calculated to be the sprayed layer 1, the critical failure load is 900kPa, the second supporting member is the secondary lining 4, the limit load is 1150kPa, the load proportion coefficient is 5.06, the sum of the safety coefficients of the sprayed layer 1 and the secondary lining 4 is higher than 4%, and the strength matching relationship is good.
In the aspect of economic analysis, compared with the first scheme, the excavation amount is increased, the thickness of the sprayed layer 1 is increased, but the using amount of the anchor rods 6 is reduced, and the non-durable anchor rods 6 can be adopted. The thickness of the spraying layer 1 in the first scheme is small, the erection requirement of a temporary steel frame (I-shaped steel I14, the thickness is 14cm) in the construction period cannot be met, and the practicability is poor.
And the result of the comprehensive comparison and selection is a second supporting scheme.
TABLE 1 calculation results of scheme one and scheme two support parameters and safety factor
Note: c30 sprayed concrete is uniformly adopted in the sprayed layer 1; the secondary lining 4 concrete adopts C30; the anchor rod 6 is a phi 22 mortar anchor rod, the first scheme adopts a durability design, and the second scheme does not adopt the durability design; denotes C35 reinforced concrete; two numerical values in the anchor rod-surrounding rock bearing arch safety coefficient respectively represent the safety coefficient in the construction period and the operation period.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (6)
1. A tunnel composite lining design method based on a total safety factor method is characterized by comprising the following steps:
s1, determining a surrounding rock pressure representative value of the composite lining;
s2, determining the value of the total safety factor of the composite lining according to the support type;
s3, preliminarily distributing the total safety coefficient of the composite lining determined in the S2 to obtain a plurality of distribution combinations, wherein each distribution combination comprises a spray layer safety coefficient, an anchor rod-surrounding rock bearing arch safety coefficient and a secondary lining safety coefficient;
s4, calculating spray layer parameters corresponding to each group of distribution combination by adopting a load structure model of a spray layer according to the spray layer safety coefficient in each group of distribution combination;
s5, calculating secondary lining parameters corresponding to each group of distribution combination by adopting a load structure model of secondary lining according to the secondary lining safety coefficient in each group of distribution combination;
s6, calculating anchor rod parameters corresponding to each group of distribution combination by adopting an anchor rod-surrounding rock bearing arch load structure model according to the safety factors of the spray layer, the secondary lining and the anchor rod-surrounding rock bearing arch in each group of distribution combination;
s7, calculating the load proportion coefficient of the overall damage stage of the composite structure corresponding to each group of distribution combination, the damage sequence of the sprayed layer and the secondary lining and the corresponding damage load by adopting a composite structure model according to the sprayed layer parameters and the secondary lining parameters calculated in each group of distribution combination;
s8, carrying out strength matching, economical efficiency and implementability ratio selection and comprehensive analysis on the supporting member according to the sprayed layer safety coefficient, the anchor rod-surrounding rock bearing arch safety coefficient and the secondary lining safety coefficient in each group of distribution groups and the sprayed layer parameter, the secondary lining parameter, the anchor rod parameter and the load proportion coefficient calculated by each group of distribution groups to obtain a more economical and reasonable supporting scheme;
the method for determining the load structure model of the sprayed layer in S4 and calculating the sprayed layer parameters in each group of distribution combination comprises the following steps:
the load structure model of the spray layer is a calculation model based on finite elements, the spray layer is simulated by adopting a beam unit, the interaction between the structure and the stratum is simulated by adopting a tension-free radial spring and a tangential spring, the rigidity of the tangential spring is 1/3 of the rigidity of the tension-free radial spring, the load adopts the surrounding rock pressure representative value in the step S1, and after the internal force of the spray layer is obtained, the spray layer parameters and the safety coefficient are calculated by adopting a damage stage method;
the method for determining the load structure model of the secondary lining in S5 and calculating the secondary lining parameters in each group of distribution combination comprises the following steps:
the load structure model of the secondary lining is a calculation model based on finite elements, the secondary lining is simulated by adopting a beam unit, the area where the waterproof board is laid on the arch wall is simulated by adopting a tension-free radial spring, the contact between the inverted arch area and the primary support is simulated by adopting a tension-free radial spring and a tangential spring, the rigidity of the tangential spring is 1/3 of the rigidity of the tension-free radial spring, and the load adopts the surrounding rock pressure representative value in the step S1; after the internal force of the secondary lining is obtained, secondary lining parameters and a safety coefficient are calculated by adopting a damage stage method;
the method for determining the load structure model of the anchor rod-surrounding rock bearing arch in the S6 and calculating the anchor rod parameters in each distribution combination comprises the following steps:
s61: pressure diffusion is carried out on the outer end of the anchor rod towards the inner side of the tunnel according to a certain angle, a connecting line formed by intersection points of adjacent anchor rods after pressure diffusion is an outer side line of the bearing arch, the inner side line of the bearing arch is the outer surface of a spray layer, the anchor rod-surrounding rock bearing arch is simulated by adopting a beam unit, interaction between surrounding rock and the bearing arch is simulated by adopting a tension-free radial spring, elastic support is adopted at an arch foot, and the load adopts the surrounding rock pressure representative value in the step S1;
s62: after the internal force of the bearing arch is obtained, anchor rod parameters and the anchor rod-surrounding rock bearing arch safety coefficient are calculated according to a damage stage method, wherein the ultimate strength of surrounding rock in the anchor rod-surrounding rock bearing arch range only considers the strength increased after supporting, and the calculation formula is as follows:
wherein: [ sigma ]c]For bearing the ultimate strength, σ, of the surrounding rock within the arch3The supporting force is provided for the spray layer, the anchor rod and the second lining;
supporting force sigma provided by anchor rods32The calculation formula is as follows:
σ32＝min[fyπd2/(4bs·ks),frbπdglg/(bs·kg)]；
wherein σ32The supporting force provided for the anchor rod; k is a radical ofsThe yield bearing capacity safety factor of the anchor rod is not less than 2.0; kg is the anti-pulling safety coefficient of the anchor rod and is not less than 2.5; f. ofyFor anchor barsThe yield strength of (d); d is the anchor bar diameter; f. ofrbThe ultimate bonding strength between the mortar anchoring body and the ground layer; dgThe outer diameter of the mortar anchoring body; lgThe anchoring length of the anchor bar and the mortar; b. s is the circumferential spacing and the longitudinal spacing of the anchor rods respectively;
supporting force sigma provided by the sprayed layer31Supporting force sigma provided by secondary lining31The calculation formula of (a) is as follows:
σ31＝0.5K1·q；
σ33＝0.5K3·q；
wherein, K1、K3Safety factors of a sprayed layer and a secondary lining are respectively set;
when the thickness of the sprayed layer is less than 8cm, the sprayed layer provides sigma31Can be ignored;
the total supporting force provided by the anchor rod, the sprayed layer and the secondary lining is taken as sigma3The values are different in the construction period and the operation period, and sigma can be adopted3cAnd σ3opThe supporting force provided by the supporting system for the surrounding rock in the anchor-rock bearing arch in the construction period and the operation period respectively has the following calculation formula:
σ3c＝σ31+σ32；
σ3op＝σ31+σ32+σ33；
s63: when the thickness of the sprayed layer of the tunnel is less than 8cm, the supporting effect of the sprayed layer is ignored, and the anchor rod needs to meet all supporting force sigma required by the anchor-rock bearing arch in the S623In addition, the requirement of minimum supporting force is also required to be met, and the calculation formula is as follows:
min[fyπd2/(4bs·ks),frbπdglg/(bs·kg)]＞Pimin；
2. the method for designing the composite tunnel lining based on the total safety factor method according to claim 1, wherein S1 specifically comprises:
when the buried depth H is more than or equal to 10-15 times of the hole diameter D, the calculation formula of the surrounding rock pressure representative value is as follows:
the vertical uniform load is that q is α gamma (R)pd-a)；
Horizontally and uniformly distributing load, wherein e is β lambda q;
wherein the content of the first and second substances,
wherein gamma is the weight of the surrounding rock, lambda is the lateral pressure coefficient of the surrounding rock, α and β are the pressure adjusting coefficients of the surrounding rock at the arch part and the side part respectively, and P is the pressure adjusting coefficient of the surrounding rock at the side partiFor the supporting force, P is taken in calculationi＝0；RpdIs the radius of the tunnel plastic zone; p0Initial stress of surrounding rock; c is the cohesive force of the surrounding rock;
the internal friction angle of the surrounding rock; theta is an included angle between theta and the transverse shaft of the tunnel, and theta is 45 degrees during calculation; r0Taking the equivalent circle radius when the section is non-circular; a is the distance from the center of the equivalent circle to the tunnel excavation boundary at the position of 45 degrees;
when the time is 2.5hq<H<(10-15) D;
wherein h isq＝0.45×2S-1ω；
Wherein S is the grade of surrounding rock; ω is the width influence coefficient, ω 1+ i (B-5); b is the width (m) of the tunnel; i is the surrounding rock pressure increase and decrease rate when the B increases and decreases by 1m, and when the B is less than 5m, i is 0.2; when B is more than 5m, i is 0.1;
solving the plastic zone range without support by adopting an elastic-plastic finite element method under actual buried depth, and taking the average plastic zone height within 90-degree range of the arch part as the equivalent height of the surrounding rock pressure representative value;
when H is present<2.5hqWhen the current is over;
the shallow buried surrounding rock pressure formula E.0.2-1-E.0.2-1 is adopted for calculation.
3. The method for designing the tunnel composite lining based on the total safety factor method according to claim 1, wherein the value of the total safety factor in S2 is satisfied:
total safety factor K in operation phaseop≥3.0～3.6；
Total safety factor K in the construction phasec≥1.8～2.1；
The total safety coefficient can be adjusted according to the structural importance, the specific conditions of surrounding rocks and construction quality control factors;
wherein, no secondary lining is adopted in the construction stage, and the total safety factor is formed by the sum of the safety factors of the spray layer and the anchor rod-surrounding rock bearing arch.
4. The method for designing the tunnel composite lining based on the total safety factor method according to claim 1, wherein the distribution principle and the distribution method for the preliminary distribution of the total safety factor of the composite lining in the step S3 are calculated by adopting the following formula:
and (3) construction stage: kc＝K1+K2；
And (3) an operation stage:
when adopting durability stock: kop＝K1+K2+K3；
When a non-durable anchor rod is adopted: kop＝K1+K3；
Wherein, K1、K2、K3Safety factors of a spray layer, an anchor-enclosure bearing arch and a secondary lining are respectively set;
wherein, no secondary lining is adopted in the construction stage, and the total safety coefficient is formed by the sum of the safety coefficients of the spray layer and the anchor rod-surrounding rock bearing arch; in the operation stage, the total safety coefficient when the durable anchor rod is adopted consists of the sum of the safety coefficients of the spray layer, the anchor rod-surrounding rock bearing arch and the secondary lining, and the total safety coefficient when the non-durable anchor rod is adopted consists of the sum of the safety coefficients of the spray layer and the secondary lining.
5. The method for designing the tunnel composite lining based on the total safety factor method according to claim 1, wherein the method for determining the composite structure model in S7 and calculating the load proportionality coefficient of the overall failure stage in each group of distribution combination comprises the following steps:
s71: the composite structure model is a calculation model based on finite elements, the spray layer and the secondary lining are simulated by adopting beam units, the interaction between the spray layer and the stratum is simulated by adopting non-pull radial springs and tangential springs, and the rigidity of the non-pull radial springs and the rigidity of the tangential springs are consistent with that of the non-pull radial springs and the tangential springs in the load structure model of the spray layer in the step S4; the interaction between the sprayed layer and the secondary lining is simulated by adopting a non-pulling radial spring between the sprayed layer and the secondary lining, and the rigidity k of the non-pulling radial spring between the sprayed layer and the secondary lining can be expressed as follows:
wherein E is1、E2The elastic modulus h of the sprayed layer and the secondary lining respectively1、h2The thicknesses of the sprayed layer and the secondary lining are respectively, and A is the area of the contact unit;
wherein the tangential spring stiffness of the secondary lining inverted arch area is consistent with that of the spray layer tangential spring;
s72: and (4) adopting the composite structure model of S71 to gradually increase the load, wherein a certain section reaches the damage stage, assuming that the section can maintain the bearing capacity of the damage stage, applying the internal force of the damage region as a boundary condition to the damage position, and then continuously increasing the load until the whole structure is damaged, wherein the load at the moment is taken as a limit load, and the ratio of the limit load to the design load is the load proportionality coefficient of the whole damage stage of the composite lining.
6. The method for designing the composite tunnel lining based on the total safety factor method according to claim 1, wherein S8 specifically comprises:
dividing the load proportion coefficient in each group of distribution combination by the sum of the safety factors of the sprayed layer and the secondary lining to serve as an index for judging the strength matching of the supporting member, wherein the ratio is always greater than 1, and the matching is better when the ratio is close to 1;
wherein the economic indicators of the supporting member comprise: excavating amount, the amount of each supporting member, personnel mechanical configuration required by each supporting measure and supporting cycle period; the implementability indexes of the supporting member include: each supporting member cannot exceed the existing construction level and cannot influence the operation conditions of other supporting members.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811496389.8A CN109667598B (en) | 2018-12-07 | 2018-12-07 | Tunnel composite lining design method based on total safety factor method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811496389.8A CN109667598B (en) | 2018-12-07 | 2018-12-07 | Tunnel composite lining design method based on total safety factor method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109667598A CN109667598A (en) | 2019-04-23 |
| CN109667598B true CN109667598B (en) | 2020-06-09 |
Family
ID=66144174
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811496389.8A Active CN109667598B (en) | 2018-12-07 | 2018-12-07 | Tunnel composite lining design method based on total safety factor method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109667598B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110206563A (en) * | 2019-06-25 | 2019-09-06 | 深圳市综合交通设计研究院有限公司 | A kind of full packet waterproof composite lining structure resistant to pressure and its construction method |
| CN110671128B (en) * | 2019-09-19 | 2020-12-29 | 中铁第四勘察设计院集团有限公司 | Method for evaluating mechanical state of secondary lining of mine tunnel |
| CN110608054B (en) * | 2019-09-30 | 2021-04-02 | 中铁第四勘察设计院集团有限公司 | Deformation prediction method and device for tunnel support structure excavated by full-section method |
| CN110909429B (en) * | 2019-11-26 | 2022-04-26 | 中铁第四勘察设计院集团有限公司 | Corrugated steel plate lining reinforcement parameter optimization design method and structure based on tunnel lining defect detection |
| CN111027129B (en) * | 2019-12-30 | 2022-09-16 | 石家庄铁道大学 | Design method of extruded surrounding rock tunnel structure |
| CN111488707B (en) * | 2020-04-21 | 2024-05-07 | 长安大学 | Design method for tunnel section parameters of single-hole four-lane highway |
| CN111581696B (en) * | 2020-04-23 | 2022-11-22 | 中铁（天津）隧道工程勘察设计有限公司 | Method for calculating safety coefficient of extra-large cross-chamber supporting structure |
| CN111691906B (en) * | 2020-05-12 | 2021-09-03 | 同济大学 | Operating tunnel anchor rod reinforcing method |
| CN112647970B (en) * | 2020-12-28 | 2022-04-26 | 中国科学院武汉岩土力学研究所 | Polyurethane large-deformation numerical simulation method for tunnel buffer support |
| CN112832809B (en) * | 2021-01-21 | 2022-09-20 | 中铁第四勘察设计院集团有限公司 | Railway tunnel expansive rock tunnel structure design method based on strength-rigidity double control |
| CN112818445B (en) * | 2021-01-25 | 2022-03-22 | 中铁第四勘察设计院集团有限公司 | Method and device for testing mechanical response of deep-buried isobaric circular composite lining tunnel |
| CN113111408B (en) * | 2021-03-17 | 2022-08-09 | 中铁第四勘察设计院集团有限公司 | Porous space small-clear-distance tunnel design method based on secondary lining post-pouring |
| CN114003993B (en) * | 2021-10-29 | 2023-05-05 | 中铁隧道局集团有限公司 | Method for evaluating repairing effect and selecting repairing scheme of tunnel fracture lining |
| CN114151107A (en) * | 2021-11-10 | 2022-03-08 | 武义县交通运输局 | Tunnel reinforcing method based on disease characteristics and safety evaluation |
| CN118070406A (en) * | 2024-04-22 | 2024-05-24 | 深圳大学 | Tunnel three-dimensional modeling design method, device, medium and product |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1870559A2 (en) * | 2006-06-21 | 2007-12-26 | Industrial Roll Formers Pty Limited | A two-stage rock bolt and method of use |
| CN104462835A (en) * | 2014-12-16 | 2015-03-25 | 湖南科技大学 | Tunnel lining safety assessing device and calculation method based on fire scenes |
| CN107066807A (en) * | 2017-02-27 | 2017-08-18 | 湖南科技大学 | It is a kind of to determine vertical shaft lining cutting security and the computational methods of optimization |
| CN108005697A (en) * | 2017-12-29 | 2018-05-08 | 中铁第四勘察设计院集团有限公司 | A kind of tunnel system Soil Anchor Design method based on method of safety coefficients |
| CN108222969A (en) * | 2017-12-29 | 2018-06-29 | 中铁第四勘察设计院集团有限公司 | A kind of Design of Tunnel method based on method of safety coefficients |
-
2018
- 2018-12-07 CN CN201811496389.8A patent/CN109667598B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1870559A2 (en) * | 2006-06-21 | 2007-12-26 | Industrial Roll Formers Pty Limited | A two-stage rock bolt and method of use |
| CN104462835A (en) * | 2014-12-16 | 2015-03-25 | 湖南科技大学 | Tunnel lining safety assessing device and calculation method based on fire scenes |
| CN107066807A (en) * | 2017-02-27 | 2017-08-18 | 湖南科技大学 | It is a kind of to determine vertical shaft lining cutting security and the computational methods of optimization |
| CN108005697A (en) * | 2017-12-29 | 2018-05-08 | 中铁第四勘察设计院集团有限公司 | A kind of tunnel system Soil Anchor Design method based on method of safety coefficients |
| CN108222969A (en) * | 2017-12-29 | 2018-06-29 | 中铁第四勘察设计院集团有限公司 | A kind of Design of Tunnel method based on method of safety coefficients |
Non-Patent Citations (1)
| Title |
|---|
| 复合式衬砌隧道的总安全系数设计方法探讨;肖明清;《铁道工程学报》;20180115(第1期);第84-88页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109667598A (en) | 2019-04-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109667598B (en) | Tunnel composite lining design method based on total safety factor method | |
| CN108005697B (en) | Tunnel system anchor rod design method based on safety coefficient method | |
| CN109885911B (en) | Tunnel composite lining design method including secondary lining under multi-load action | |
| CN104264899B (en) | Embedded outsourcing U-shaped steel-concrete composite beam | |
| CN204551241U (en) | A kind of crack resistance type seamless bridge bridge abutment structure with X muscle | |
| CN109853381B (en) | Transitional structure for preventing bridge head from jumping and construction method thereof | |
| CN203923924U (en) | No. 0 section bracket prepressing device | |
| CN102364012B (en) | Method for expanding existing large-span truss | |
| CN104652293A (en) | Cable-stayed bridge structure used for reinforcing PSC (Pre-stressed Concrete) continuous box girder bridge and construction method | |
| CN204001813U (en) | A kind of existing reinforced concrete floor or roof panel ruggedized construction | |
| CN103147385B (en) | Double-spliced extradosed cable-stayed bridge | |
| CN103966953B (en) | Based on the post-tensioned prestressed large-span concrete beam construction method of non-bending steel cable | |
| CN104831639B (en) | A kind of ultra-wide nonprismatic continuous beam 0# block consolidation and releasing construction method | |
| CN103726586A (en) | H-shaped steel and steel plate framework assembly shear wall with interfaces with grooves and manufacturing method | |
| CN106869012A (en) | Using the prefabricated thin-wall bent cap of prestressing with bond system | |
| CN104652242A (en) | Derrick connecting structure used for reinforcing PSC (Pre-stressed Concrete) continuous box girder bridge and construction method | |
| WO2012031459A1 (en) | Long segment structure of offshore high pile wharf | |
| CN103352578B (en) | A kind of construction method of carbon fiber cloth steel member composite reinforcement beam | |
| CN104652244B (en) | A kind of Suspension bridge structure for reinforcing PSC Continuous Box Girder Bridge and construction method | |
| CN109457608A (en) | A kind of construction method of prefabricated steel reinforced concrete combined bridge deck | |
| CN105631190A (en) | Reinforcement method of concrete deep beam | |
| CN107761580A (en) | A kind of old pier stud rebuilding construction scheme of bridge | |
| CN209523119U (en) | A kind of prefabricated steel reinforced concrete combined bridge deck | |
| CN206635638U (en) | Using the prefabricated thin-wall bent cap of prestressing with bond system | |
| CN202866315U (en) | Outer sleeved frame story adding structure accepting cushion block |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |