CN106529002B - A kind of Design and analysis methods of tunnel steelframe Auxiliary support system - Google Patents

Abstract

The present invention relates to Tunnel Engineering fields, and in particular to a kind of Design and analysis methods of tunnel steelframe Auxiliary support system.According to the mechanism of action of steelframe Auxiliary support system, the mechanics analysis model for establishing steelframe Auxiliary support system solves the stress and deformation of the foundation load of each arch springing of steelframe when different operating conditions under steelframe Auxiliary support system support action can be obtained, arch springing settling amount, the internal force in each section of longitudinal beam connected, each lock foot component and its ground that underlies through force method.Tunnel Design personnel can utilize the stress and deformation of the foundation load of each arch springing of gained steelframe, each arch springing settling amount, each force on cross-section of longitudinal beam connected, lock foot component and its ground that underlies, the bearing capacity of each arch springing ground of steelframe when to different operating conditions, each arch springing settling amount, longitudinal beam connected and each lock foot component the underlie bearing capacity of ground of intensity and lock foot component check, be finally completed the design of steelframe Auxiliary support system.

Description

A kind of Design and analysis methods of tunnel steelframe Auxiliary support system

One, technical field:

The present invention relates to Tunnel Engineering fields, and in particular to a kind of design analysis side of tunnel steelframe Auxiliary support system Method.

Two, background technique:

Steelframe is a kind of weak broken formation tunnel commonly preliminary bracing pattern, since to have biggish early stage rigid for it Degree, can give country rock strong supporting immediately after erection, therefore the country rock initial stage after maintaining tunnel excavation stablizes Aspect, steelframe can play a significant role.However, the landslide or hole top that occur in investigation soft stratum constructing tunnel are substantially sunk Drop, problem then mostly occurs in the arch springing bearing of steelframe, such as arch springing foundation bearing capacity is insufficient or arch springing vacantly can be to steelframe The stability of arch springing adversely affects.

The Auxiliary support system of steelframe is a kind of currently used tunnel arch foot settlement Control measure, but still lack it is a set of can For Tunnel Design personnel use design analysis and evaluation method, cause using it is upper only by rule of thumb and there are biggish blindness.

Three, summary of the invention

Of the invention provides a kind of Design and analysis methods of tunnel steelframe Auxiliary support system.

To achieve the above object, a kind of the technical solution adopted by the present invention are as follows: design of tunnel steelframe Auxiliary support system Analysis method, it is characterised in that: the method and step are as follows:

Step 1): the mechanics analysis model of steelframe Auxiliary support system is established, the steelframe Auxiliary support system is by even It connects stringer and lock foot component is constituted；

Step 2): the mechanics analysis model established according to step 1) determines in steelframe Auxiliary support system on longitudinal beam connected The vertical imposed load of each steelframe transmitting in side；

Step 3): the vertical imposed load that the mechanics analysis model and step 2) established according to step 1) determine, using power Method determines the redundant force of longitudinal beam connected everywhere in steelframe Auxiliary support system；

Step 4): according to the resulting redundant force of step 3), the foundation load of each arch springing of steelframe when determining different operating conditions, The stress condition of each arch springing settling amount, the internal force in each section of longitudinal beam connected, lock foot component and its ground that underlies；

Step 5): according to foundation load, each arch springing settling amount, each section of longitudinal beam connected of each arch springing of steelframe that step 4) determines The internal force in face, the stress condition for locking foot component and its ground that underlies, the foundation bearing capacity of each arch springing, each arch springing when to different operating conditions Settling amount, longitudinal beam connected intensity, lock the intensity of foot component and its bearing capacity of the ground that underlies is checked, if being unsatisfactory for checking It is required that must then adjust the design parameter of steelframe Auxiliary support system, checking computations require until meeting checking computations again.

The mechanics analysis model for the steelframe Auxiliary support system that the step 1) is established meets the following conditions:

A: longitudinal beam connected is considered as fixing end at the bottomed spreading of steelframe, the longitudinal beam connected of the non-long joining section of steelframe is considered as cantilever Girder construction；

B: the vertical imposed load that the non-long joining section of steelframe transmits from top to bottom is by longitudinal beam connected, lock foot component and arch springing ground Common bearing.For longitudinal beam connected, by the vertical imposed load that steelframe each above stringer transmits, while also by each lock The vertical subgrade reaction of each arch springing transmitting of steelframe below the vertical support counter-force and stringer that foot component provides.The lock foot structure The bearing that part and steelframe arch springing ground provide is accordingly to be regarded as elastic bearing, and suffered subgrade reaction obeys Winkler's assumption, wherein The elastic supporting rigidity of each arch springing ground of steelframe is respectively K₁、K₂、K₃、K₄And K₅Deng each to lock the elastic bearing that foot component provides rigid Degree is respectively K_s1、K_s2、K_s3、K_s4、K_s5And K_s6；

C: the spring rate K by enabling steelframe arch springing ground₁=0, to consider that step lower part is excavated to hanging caused ground The loss of base supporting force.

The step 2) determines the vertical imposed load of each steelframe transmitting above longitudinal beam connected in steelframe Auxiliary support system, The vertical load takes two kinds of extreme cases to carry out envelope value.

Redundant force includes the vertical subgrade reaction of each arch springing of steelframe and respectively locks foot component to even in the step 3) Connect the bearing reaction of stringer.

It is required according to the checking computations of the step 5) are as follows:

A, each arch springing foundation load, which is less than ground, allows load or stress；

B, each arch springing settling amount is less than permissible value；

C, the stress of longitudinal beam connected is less than the yield strength of stringer material；

D, the stress for locking foot component is less than the yield strength of construction material；

E, lock foot component underlies ground stress less than ground permission load or stress.

Compared with prior art, the invention has the advantages that and effect:

The present invention is calculated by establishing the mechanics analysis model of steelframe Auxiliary support system (longitudinal beam connected+lock foot component) Obtain the foundation load of each arch springing of steelframe under steelframe Auxiliary support system (longitudinal beam connected+lock foot component) supporting, the sedimentation of each arch springing Amount, each section of longitudinal beam connected internal force, lock foot component and its ground that underlies stress condition, and then can be to different operating conditions when steelframe The reasonability of Auxiliary support system (longitudinal beam connected+lock foot component) design is checked, and steelframe Auxiliary support system is finally completed The design of (longitudinal beam connected+lock foot component).Steelframe Auxiliary support system (longitudinal beam connected+lock foot component) of the invention designs analysis Method can provide theoretical foundation for the design of steelframe Auxiliary support system (longitudinal beam connected+lock foot component), avoid current steelframe Auxiliary support system (longitudinal beam connected+lock foot component) is designing and the upper only existing blindness by rule of thumb of application.

Longitudinal beam connected, lock foot component of steelframe etc. are the common arch springing settlement Control measures of steelframe, with longitudinal beam connected or lock The exclusive use of foot component is compared, and the two, which is used in combination, obviously has better settlement Control effect.Support system (the longitudinal beam connected + lock foot component) support action be mainly manifested in it is following two aspect: first is that by longitudinal beam connected and lock foot component to top steelframe Common supporting role, share or reduce top steelframe and pass to the foundation load of arch springing, to avoid due to foundation bearing capacity Steelframe arch springing unstability caused by deficiency；Second is that when step lower part be excavated to steelframe arch springing it is hanging when, by longitudinal beam connected and lock foot Component provides bearing jointly for the steelframe of vacant state, so that it is guaranteed that stability of the steelframe in the work progress of step lower part.

Four, Detailed description of the invention:

Fig. 1 is a kind of process of the Design and analysis methods of tunnel steelframe Auxiliary support system (longitudinal beam connected+lock foot component) Figure；

Fig. 2 a is the schematic diagram of steelframe Auxiliary support system (longitudinal beam connected+lock foot component) along tunnel longitudinal direction；

Fig. 2 b is steelframe Auxiliary support system (longitudinal beam connected+lock foot component) along the schematic diagram of tunnel lateral direction；

Fig. 3 a is steelframe Auxiliary support system (longitudinal beam connected+lock foot component) mechanics schematic diagram in reality；

Fig. 3 b is the idealized model schematic diagram of steelframe Auxiliary support system (longitudinal beam connected+lock foot component)；

Fig. 4 a is that load when country rock load is uniformly distributed along longitudinal direction distributes schematic diagram；

Fig. 4 b is that arch springing load transmits schematic diagram；

Fig. 5 a is the schematic diagram of country rock load distribution triangular in shape along longitudinal direction；

Fig. 5 b be country rock load along longitudinal direction distribution triangular in shape when load distribute schematic diagram；

Fig. 6 is the force method primary structure that steelframe Auxiliary support system (longitudinal beam connected+lock foot component) redundant force solves Schematic diagram.

Five, specific embodiment

Technical solution of the present invention is described in further detail below with reference to specific embodiment:

A kind of Design and analysis methods step of tunnel steelframe Auxiliary support system are as follows:

Step 1): the mechanics analysis model of steelframe Auxiliary support system is established, the steelframe Auxiliary support system is by even It connects stringer and lock foot component is constituted；

The mechanics analysis model for the steelframe Auxiliary support system that the step 1) is established meets the following conditions:

A: longitudinal beam connected is considered as fixing end at the bottomed spreading of steelframe, the longitudinal beam connected of the non-long joining section of steelframe is considered as cantilever Girder construction；

B: the vertical imposed load that the non-long joining section of steelframe transmits from top to bottom is by longitudinal beam connected, lock foot component and arch springing ground Common bearing.For longitudinal beam connected, by the vertical imposed load that steelframe each above stringer transmits, while also by each lock The vertical subgrade reaction of each arch springing transmitting of steelframe below the vertical support counter-force and stringer that foot component provides.The lock foot structure The bearing that part and steelframe arch springing ground provide is accordingly to be regarded as elastic bearing, and suffered subgrade reaction obeys Winkler's assumption, wherein The elastic supporting rigidity of each arch springing ground of steelframe is respectively K₁、K₂、K₃、K₄And K₅Deng each to lock the elastic bearing that foot component provides rigid Degree is respectively K_s1、K_s2、K_s3、K_s4、K_s5And K_s6；

C: the spring rate K by enabling steelframe arch springing ground₁=0, to consider that step lower part is excavated to hanging caused ground The loss of base supporting force.

Step 2): the mechanics analysis model established according to step 1) determines in steelframe Auxiliary support system on longitudinal beam connected The vertical imposed load of each steelframe transmitting in side, vertical load take two kinds of extreme cases to carry out envelope value.

Step 3): the vertical imposed load that the mechanics analysis model and step 2) established according to step 1) determine, using power Method determines the redundant force of longitudinal beam connected everywhere in steelframe Auxiliary support system；Redundant force includes the perpendicular of each arch springing of steelframe To subgrade reaction and each foot component of locking to the bearing reaction of longitudinal beam connected.

Step 4): according to the resulting redundant force of step 3), the foundation load of each arch springing of steelframe when determining different operating conditions, The stress condition of each arch springing settling amount, the internal force in each section of longitudinal beam connected, lock foot component and its ground that underlies；

Step 5): according to foundation load, each arch springing settling amount, each section of longitudinal beam connected of each arch springing of steelframe that step 4) determines The internal force in face, the stress condition for locking foot component and its ground that underlies, the foundation bearing capacity of each arch springing, each arch springing when to different operating conditions Settling amount, longitudinal beam connected intensity, lock the intensity of foot component and its bearing capacity of the ground that underlies is checked, if being unsatisfactory for checking It is required that must then adjust the design parameter of steelframe Auxiliary support system, checking computations require until meeting checking computations again.

Checking computations require are as follows:

A, each arch springing foundation load, which is less than ground, allows load or stress；

B, each arch springing settling amount is less than permissible value；

C, the stress of longitudinal beam connected is less than the yield strength of stringer material；

D, the stress for locking foot component is less than the yield strength of construction material；

E, lock foot component underlies ground stress less than ground permission load or stress.

Embodiment:

As shown in Figure 1, the design method, first according to steelframe Auxiliary support system (longitudinal beam connected+lock foot component) Mechanism of action establishes the mechanics analysis model of steelframe Auxiliary support system (longitudinal beam connected+lock foot component) as shown in Fig. 2 a and b, As shown in Fig. 3 a and b, and meet following condition:

(1) longitudinal beam connected is considered as fixing end at the bottomed spreading of steelframe, the longitudinal beam connected of the non-long joining section of steelframe is considered as outstanding Arm girder construction；

(2) vertical imposed load that the non-long joining section of steelframe transmits from top to bottom is by longitudinal beam connected, lock foot component and arch springing Base supports jointly.For longitudinal beam connected, by the vertical imposed load that steelframe each above stringer transmits, while also by each Lock the vertical subgrade reaction of each arch springing transmitting of steelframe below the vertical support counter-force and stringer that foot component provides.The lock foot The bearing that component and steelframe arch springing ground provide is accordingly to be regarded as elastic bearing, and suffered subgrade reaction obeys Winkler's assumption, The elastic supporting rigidity of middle each arch springing ground of steelframe is respectively K₁、K₂、K₃、K₄And K₅Deng each elastic bearing locking foot component and providing Rigidity is respectively K_s1、K_s2、K_s3、K_s4、K_s5And K_s6Deng；

C: the spring rate K by enabling steelframe arch springing ground₁=0, to consider that step lower part is excavated to hanging caused ground The loss of base supporting force.

For the vertical imposed load for determining each steelframe transmitting above longitudinal beam connected, two kinds of extreme cases is taken to carry out envelope value (actual conditions always between two it is extreme between):

A: vertical country rock load is longitudinally to be uniformly distributed along tunnel, that is, disregards support of the Rock And Soil to country rock in front of working face Effect, as shown in Fig. 4 a and b, then has F₁=F₂=F₃=F₄=F₅=F.In view of the gradually release of country rock load, different loads Load intensity suffered by single Pin steelframe under release coefficient η are as follows:

Q=η q₀L_s (1)

And then it can determine the vertical imposed load of each steelframe transmitting above longitudinal beam connected are as follows:

The η is the country rock load combination ratio that steelframe undertakes；The q₀It, can be by related tunnel for the total vertical country rock load in tunnel Road design specification carries out calculating value (N/m)；The L_sFor the longitudinal pitch (m) of steelframe；The l is top bar excavation width (m)。

B: country rock load is longitudinally Triangle-Profile along tunnel, i.e., country rock load is zero at working face, then as work Make identity distance linearly to increase from increase, finally reaches maximum at the bottomed spreading of steelframe, as shown in Fig. 5 a and b.Next true Before determining the load that steelframe passes to longitudinal beam connected, it need to determine first under current country rock load assignment form apportioned by each Pin steelframe Country rock load, realization convert EDS maps load to the line distributed load acted on each Pin steelframe.In EDS maps load In any fore-and-aft plane, respective load distribution area is divided for each Pin steelframe, while ensuring the position of form center of each distribution area It is corresponding with each Pin steelframe position, it is then to act on each Pin steelframe by the distributed load equivalency transform in each distribution area On load, and then the vertical imposed load for acquiring each steelframe transmitting above longitudinal beam connected can respectively indicate are as follows:

It is erected using the mechanics analysis model of the steelframe Auxiliary support system (longitudinal beam connected+lock foot component) of foundation with what is determined To imposed load, force analysis is carried out to steelframe Auxiliary support system (longitudinal beam connected+lock foot component).Steelframe auxiliary branch is taken first The force method primary structure of support body system (longitudinal beam connected+lock foot component) is as shown in fig. 6, using force method to the steelframe Auxiliary support body It is the redundant force X of longitudinal beam connected everywhere in (longitudinal beam connected+lock foot component)₁、X₂、X₃、X₄、X₅、X₆、X₇、X₈、X₉、X₁₀With X₁₁It is solved.Redundant force X₁、X₂、X₃、X₄、X₅、X₆、X₇、X₈、X₉、X₁₀And X₁₁Solution procedure it is as follows:

In conjunction with Fig. 6, according to longitudinal beam connected in steelframe Auxiliary support system (longitudinal beam connected+lock foot component) in each steelframe arch springing The vertical displacement at place is equal to the vertical position of the compressive deformation and longitudinal beam connected of corresponding arch springing ground at each lock foot member supporting The vertical component for being equal to corresponding lock foot component ends amount of deflection is moved, following fundamental equation can be arranged:

Wherein

δ₂₁=δ₁₂,

δ₃₁=δ₁₃, δ₃₂=δ₂₃,

δ₄₁=δ₁₄, δ₄₂=δ₂₄, δ₄₃=δ₃₄

δ₅₁=δ₁₅, δ₅₂=δ₂₅, δ₅₃=δ₅₃, δ₅₄=δ₄₅

δ₆₁=δ₁₆, δ₆₂=δ₂₆, δ₆₃=δ₃₆, δ₆₄=δ₄₆, δ₆₅=δ₅₆

δ₇₁=δ₁₇, δ₇₂=δ₂₇, δ₇₃=δ₃₇, δ₇₄=δ₄₇, δ₇₅=δ₅₇, δ₇₆=δ₆₇

δ₈₁=δ₁₈, δ₈₂=δ₂₈, δ₈₃=δ₃₈, δ₈₄=δ₄₈, δ₈₅=δ₅₈, δ₈₆=δ₆₈

δ₈₇=δ₇₈,

δ₉₁=δ₁₉, δ₉₂=δ₂₉, δ₉₃=δ₃₉, δ₉₄=δ₄₉

δ₉₅=δ₅₉, δ₉₆=δ₆₉, δ₉₇=δ₇₉, δ₉₈=δ₈₉

δ₁₀₁=δ₁₁₀, δ₁₀₂=δ₂₁₀, δ₁₀₃=δ₃₁₀, δ₁₀₄=δ₄₁₀δ₁₀₅=δ₅₁₀, δ₁₀₆=δ₆₁₀, δ₁₀₇=δ₇₁₀, δ₁₀₈= δ₈₁₀, δ₁₀₉=δ₉₁₀

δ₁₁₁=δ₁₁₁, δ₁₁₂=δ₂₁₁, δ₁₁₃=δ₃₁₁, δ₁₁₄=δ₄₁₁, δ₁₁₅=δ₅₁₁

δ₁₁₆=δ₆₁₁, δ₁₁₇=δ₇₁₁, δ₁₁₈=δ₈₁₁, δ₁₁₉=δ₉₁₁, δ₁₁₁₀=δ₁₀₁₁

The X₂、X₄、X₆、X₈、X₁₀Respectively under steelframe Auxiliary support system (longitudinal beam connected+lock foot component) support action Vertical subgrade reaction at each arch springing of steelframe；The X₁、X₃、X₅、X₇、X₉And X₁₁Respectively each lock foot component mentions longitudinal beam connected The vertical support counter-force of confession；The K₁、K₂、K₃、K₄And K₅The respectively elastic supporting rigidity of each arch springing ground of steelframe, unit N/ M, and have K₁=K₂=K₃=K₄=K₅=K_fA_f；The K_fFor the coefficient of subgrade reaction of arch springing substrate, unit MPa/m；The A_f For the contact area of steelframe arch springing and substrate ground, unit m²；The K_s1、K_s2、K_s3、K_s4、K_s5And K_s6Respectively each lock foot The elastic supporting rigidity that component provides, unit N/m, and have

Wherein The L is the length for locking foot component, unit m；K is the coefficient of subgrade reaction for locking foot component underlying country rock, unit MPa/m；D For the width (or diameter) for locking foot component, unit m；EI is the bending stiffness for locking foot component, unit Nm²；The L_h= L_s/ 2, unit m；The δ_ikIt is basic structure in X_kUnder=1 effect, along unknown force X_iThe displacement that direction generates, wherein i, k= 1,2,3,4,5,6,7,8,9,10,11；The Δ_ipIt is basic structure in load F₁、F₂、F₃、F₄And F₅Under collective effect, along not Know power X_iThe displacement that direction generates, wherein i=1,2,3,4,5,6,7,8,9,10,11；The Δ_iFkIt is basic structure in F_kEffect Under, along unknown force X_iThe displacement that direction generates, wherein i=1,2,3,4,5,6,7,8,9,10,11, k=1,2,3,4,5；It is described E_bI_bFor the bending stiffness of longitudinal beam connected, unit Nm²。

Arrangement formula (6), solve in steelframe Auxiliary support system (longitudinal beam connected+lock foot component) suffered by longitudinal beam connected it is extra not Know power X₁、X₂、X₃、X₄、X₅、X₆、X₇、X₈、X₉、X₁₀And X₁₁Equation group can further indicate that are as follows:

In formula

a₁₁=δ₁₁+1/K_s1 a₁₂=δ₁₂ a₁₃=δ₁₃ a₁₄=δ₁₄ a₁₅=δ₁₅ a₁₆=δ₁₆

a₁₇=δ₁₇ a₁₈=δ₁₈ a₁₉=δ₁₉ a₁₁₀=δ₁₁₀ a₁₁₁=δ₁₁₁ b₁₀=Δ_1p

a₂₁=δ₂₁ a₂₂=δ₂₂+1/K₁ a₂₃=δ₂₃ a₂₄=δ₂₄ a₂₅=δ₂₅ a₂₆=δ₂₆

a₂₇=δ₂₇ a₂₈=δ₂₈ a₂₉=δ₂₉ a₂₁₀=δ₂₁₀ a₂₁₁=δ₂₁₁ b₂₀=Δ_2p

a₃₁=δ₃₁ a₃₂=δ₃₂ a₃₃=δ₃₃+1/K_s2 a₃₄=δ₃₄ a₃₅=δ₃₅ a₃₆=δ₃₆

a₃₇=δ₃₇ a₃₈=δ₃₈ a₃₉=δ₃₉ a₃₁₀=δ₃₁₀ a₃₁₁=δ₃₁₁ b₃₀=Δ_3p

a₄₁=δ₄₁ a₄₂=δ₄₂ a₄₃=δ₄₃ a₄₄=δ₄₄+1/K₂ a₄₅=δ₄₅ a₄₆=δ₄₆

a₄₇=δ₄₇ a₄₈=δ₄₈ a₄₉=δ₄₉ a₄₁₀=δ₄₁₀ a₄₁₁=δ₄₁₁ b₄₀=Δ_4p

a₅₁=δ₅₁ a₅₂=δ₅₂ a₅₃=δ₅₃ a₅₄=δ₅₄ a₅₅=δ₅₅+1/K_s3 a₅₆=δ₅₆

a₅₇=δ₅₇ a₅₈=δ₅₈ a₅₉=δ₅₉ a₅₁₀=δ₅₁₀ a₅₁₁=δ₅₁₁ b₅₀=Δ_5p

a₆₁=δ₆₁ a₆₂=δ₆₂ a₆₃=δ₆₃ a₆₄=δ₆₄ a₆₅=δ₆₅ a₆₆=δ₆₆+1/K₃

a₆₇=δ₆₇ a₆₈=δ₆₈ a₆₉=δ₆₉ a₆₁₀=δ₆₁₀ a₆₁₁=δ₆₁₁ b₆₀=Δ_6p

a₇₁=δ₇₁ a₇₂=δ₇₂ a₇₃=δ₇₃ a₇₄=δ₇₄ a₇₅=δ₇₅ a₇₆=δ₇₆

a₇₇=δ₇₇+1/K_s4 a₇₈=δ₇₈ a₇₉=δ₇₉ a₇₁₀=δ₇₁₀ a₇₁₁=δ₇₁₁ b₇₀=Δ_7p

a₈₁=δ₈₁ a₈₂=δ₈₂ a₈₃=δ₈₃ a₈₄=δ₈₄ a₈₅=δ₈₅ a₈₆=δ₈₆

a₈₇=δ₈₇ a₈₈=δ₈₈+1/K₄ a₈₉=δ₈₉ a₈₁₀=δ₈₁₀ a₈₁₁=δ₈₁₁ b₈₀=Δ_8p

a₉₁=δ₉₁ a₉₂=δ₉₂ a₉₃=δ₉₃ a₉₄=δ₉₄ a₉₅=δ₉₅ a₉₆=δ₉₆

a₉₇=δ₉₇ a₉₈=δ₉₈ a₉₉=δ₉₉+1/K_s5 a₉₁₀=δ₉₁₀ a₉₁₁=δ₉₁₁ b₉₀=Δ_9p

a₁₀₁=δ₁₀₁ a₁₀₂=δ₁₀₂ a₁₀₃=δ₁₀₃ a₁₀₄=δ₁₀₄ a₁₀₅=δ₁₀₅ a₁₀₆=δ₁₀₆

a₁₀₇=δ₁₀₇ a₁₀₈=δ₁₀₈ a₁₀₉=δ₁₀₉ a₁₀₁₀=δ₁₀₁₀+1/K₅ a₁₀₁₁=δ₁₀₁₁ b₁₀₀=Δ_10p

a₁₁₁=δ₁₁₁ a₁₁₂=δ₁₁₂ a₁₁₃=δ₁₁₃ a₁₁₄=δ₁₁₄ a₁₁₅=δ₁₁₅ a₁₁₆=δ₁₁₆

a₁₁₇=δ₁₁₇ a₁₁₈=δ₁₁₈ a₁₁₉=δ₁₁₉ a₁₁₁₀=δ₁₁₁₀ a₁₁₁₁=δ₁₁₁₁+1/K_s6 b₁₁₀=Δ_11p

Solving equations (7), can acquire redundant force are as follows:

Wherein

According to the redundant force X₁、X₂、X₃、X₄、X₅、X₆、X₇、X₈、X₉、X₁₀And X₁₁, and then can determine Auxiliary support Foundation load, each arch springing settling amount, the longitudinal beam connected of each arch springing of steelframe are each under system (longitudinal beam connected+lock foot component) support action The internal force in section, the stress condition for locking foot component and its ground that underlies, process are as follows:

1, the ground under steelframe Auxiliary support system (longitudinal beam connected+lock foot component) support action at each arch springing of steelframe is determined Load:

N₁=X₂ N₂=X₄ N₃=X₆ N₄=X₈ N₅=X₁₀ (9)

2, it determines each arch springing settling amount: by Winkler's assumption, steelframe Auxiliary support system (longitudinal beam connected+lock foot structure can be obtained Part) under support action, the vertical compressive deformation of each arch springing ground of steelframe, that is, arch springing sedimentation before step lower part is excavated are as follows:

A drilling depth, which is excavated, when step lower part vacantly (enables subgrade spring stiffness K to steelframe arch springing₁=0) when, arch springing at this Corresponding sedimentation are as follows:

3, the internal force in each section of longitudinal beam connected is determined

Acquire redundant force X₁、X₂、X₃、X₄、X₅、X₆、X₇、X₈、X₉、X₁₀And X₁₁Afterwards, steelframe Auxiliary support system (connects Connect stringer+lock foot component) in longitudinal beam connected become statically determinate structure.According to Fig. 6, the internal force in each section of longitudinal beam connected can be acquired.

4, the stress condition of lock foot component and its ground that underlies is determined

In the vertical support counter-force X for determining that lock foot component provides longitudinal beam connected₁、X₃、X₅、X₇、X₉And X₁₁Afterwards, according to bullet Property ground beam theory can acquire it is each lock foot component and its ground that underlies stress condition.

Finally, to the ground of each arch springing of steelframe under steelframe Auxiliary support system (longitudinal beam connected+lock foot component) support action Bearing capacity, each arch springing settling amount, longitudinal beam connected and lock foot component intensity and lock foot component underlie ground bearing capacity carry out Checking computations.Following checking computations requirement should be met: the foundation load of each arch springing, which is less than ground, allows load or stress；Each arch springing settling amount is small In permissible value；The stress of longitudinal beam connected is less than the yield strength of stringer material；The stress of each lock foot component is less than construction material Yield strength；Each lock foot component underlies ground stress less than ground permission load or stress.If being unsatisfactory for checking computations to require, must adjust The design parameter of whole steelframe Auxiliary support system (longitudinal beam connected+lock foot component), checking computations require until meeting checking computations again, finally Complete the design of tunnel steelframe Auxiliary support system (longitudinal beam connected+lock foot component).

Claims (1)

1. a kind of Design and analysis methods of tunnel steelframe Auxiliary support system, it is characterised in that: the method step are as follows:

Step 1): establishing the mechanics analysis model of steelframe Auxiliary support system, and the steelframe Auxiliary support system is vertical by connecting Beam and lock foot component are constituted；

Step 2): the mechanics analysis model established according to step 1) determines each above longitudinal beam connected in steelframe Auxiliary support system The vertical imposed load of steelframe transmitting；

Step 3): the vertical imposed load that the mechanics analysis model and step 2) established according to step 1) determine, it is true using force method Determine the redundant force of longitudinal beam connected everywhere in steelframe Auxiliary support system；

Step 4): according to the resulting redundant force of step 3), the foundation load of each arch springing of steelframe, each arch when determining different operating conditions The internal force in each section of foot settling amount, longitudinal beam connected, the stress condition for locking foot component and its ground that underlies；

Step 5): the foundation load of each arch springing of steelframe that is determined according to step 4), each arch springing settling amount, each section of longitudinal beam connected The stress condition of internal force, lock foot component and its ground that underlies, the foundation bearing capacity of each arch springing, the sedimentation of each arch springing when to different operating conditions Amount, the intensity of longitudinal beam connected, the intensity for locking foot component and its bearing capacity of the ground that underlies are checked；If being unsatisfactory for checking computations to want It asks, then must adjust the design parameter of steelframe Auxiliary support system, checking computations require until meeting checking computations again；

The mechanics analysis model for the steelframe Auxiliary support system that the step 1) is established meets the following conditions:

A: longitudinal beam connected is considered as fixing end at the bottomed spreading of steelframe, the longitudinal beam connected of the non-long joining section of steelframe is considered as cantilever beam knot Structure；

B: the vertical imposed load that the non-long joining section of steelframe transmits from top to bottom is common by longitudinal beam connected, lock foot component and arch springing ground Bearing, for longitudinal beam connected, by the vertical imposed load that steelframe each above stringer transmits, while also by each lock foot structure The vertical subgrade reaction of each arch springing transmitting of steelframe below the vertical support counter-force and stringer that part provides；The lock foot component and The bearing that steelframe arch springing ground provides is accordingly to be regarded as elastic bearing, and suffered subgrade reaction obeys Winkler's assumption, wherein steelframe The elastic supporting rigidity of each arch springing ground is respectively K₁、K₂、K₃、K₄And K₅, each elastic supporting rigidity difference locking foot component and providing For K_s1、K_s2、K_s3、K_s4、K_s5And K_s6；

C: the elastic supporting rigidity K by enabling steelframe arch springing ground₁=0, to consider that step lower part is excavated to hanging caused ground Supporting force loss；

The step 2) determines the vertical imposed load of each steelframe transmitting above longitudinal beam connected in steelframe Auxiliary support system, described Vertical load takes two kinds of extreme cases to carry out envelope value, and two kinds of extreme cases are a, country rock load uniformly divides along longitudinal direction Cloth；B, country rock load has a generally triangular shape distribution along longitudinal direction；

Redundant force includes that the vertical subgrade reaction of each arch springing of steelframe and each lock foot component indulge connection in the step 3) The bearing reaction of beam；

It is required according to the checking computations of the step 5) are as follows:

A, each arch springing foundation load, which is less than ground, allows load；

B, each arch springing settling amount is less than permissible value；

C, the stress of longitudinal beam connected is less than the yield strength of stringer material；

D, the stress for locking foot component is less than the yield strength of construction material；

E, lock foot component underlies ground stress less than ground permission load.