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Tunnel step method discrimination method

A discriminant method, a technology of the step method, which is applied in the field of tunnel and underground engineering, and can solve problems such as the lack of systematic theoretical calculation basis for the construction of the step method

Active Publication Date: 2020-07-31
RES INST OF HIGHWAY MINIST OF TRANSPORT +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Specifically, the technical problem to be solved by the present invention is to provide a method for discriminating the tunnel step method to solve the technical problem of the lack of systematic theoretical calculation basis for the step method construction in the existing tunnel construction

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] Embodiment one: if figure 1 Shown, a kind of discrimination method of tunnel step method, this method comprises the following steps:

[0083] (1) Determine the overall excavation height of the tunnel;

[0084] (2) Calculate the maximum value of the one-time excavation height of the tunnel;

[0085] (3) According to the relationship between the overall tunnel excavation height and the maximum one-time excavation height, determine whether the tunnel excavation adopts the step method.

[0086] This method uses the relationship between the one-time excavation height and the overall excavation height of the tunnel to judge, among them, if the overall excavation height of the tunnel H A Greater than the maximum allowable one-time excavation height H of the tunnel max , the step method should be adopted for construction, if the overall tunnel excavation height H A Less than the maximum allowable one-time excavation height H of the tunnel max , then the full-section excava...

Embodiment 2

[0150] Embodiment two: embodiment two is basically the same as embodiment one, and its difference is: as figure 2 As shown, when the tunnel is excavated by steps, it is assumed that the loose collapse range of the top of the tunnel is a simply supported beam (ABCD). for:

[0151]

[0152] In the formula: L is the excavation span of the tunnel; h is the thickness of the simply supported beam (ABCD); the weight of the surrounding rock is ρg.

[0153] According to the relevant theory in material mechanics, the maximum tensile stress on the beam section is:

[0154]

[0155] When stable, the maximum tensile stress should be less than the tensile strength value of the surrounding rock, that is, the maximum tensile stress should satisfy:

[0156] σ max ≤σ t ;

[0157] Where: σ t is the design value of the tensile strength of the tunnel surrounding rock.

[0158] which is:

[0159]

[0160]

[0161] Such as image 3 As shown, when the tunnel is excavated, the coll...

Embodiment 3

[0184] Embodiment 3: The tunnel is a V-level surrounding rock tunnel, and the known mechanical parameters of the surrounding rock of the tunnel are taken as follows:

[0185] ρg (surrounding rock weight) = 20kN / m 3 ;

[0186] C (surrounding rock cohesion) = 0.1MPa;

[0187]

[0188]

[0189] σ t (Design value of tensile strength of tunnel surrounding rock) = 0.12MPa.

[0190] The excavation profile of the tunnel is an elliptical section, the overall excavation height of the tunnel is 10m, and the excavation span is 6m. The excavation profile function of the elliptical section is expressed as:

[0191]

[0192] The function of angle is:

[0193]

[0194] sinα=sin57°=0.838;

[0195] cosα = cos57° = 0.544;

[0196] cotα=cot57°=0.649.

[0197] The specific calculation process includes the following four steps:

[0198] (1) If the tunnel excavation is safe, the parameters of the tunnel excavation profile need to satisfy the relationship of three tunnel instabili...

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Abstract

The invention relates to the technical field of tunnels and underground engineering, in particular to a tunnel step method discrimination method, which comprises the following steps of: (1) determining an overall excavation height of a tunnel; (2) calculating a maximum value of the one-time excavation height of the tunnel; (3) and determining whether to adopt a step method for tunnel excavation ornot according to a relationship between the overall excavation height of the tunnel and the maximum one-time excavation height. Compared with the prior art, the tunnel step method discrimination method has the beneficial effects that: based on the common collapse types in tunnel construction, three tunnel surrounding rock collapse instability modes and collapse instability theoretical discrimination formulas are provided, on the basis, the relation between the sizes of steps and surrounding rock stability during tunnel step method construction is constructed, the one-time excavation height ofthe steps in the step method is obtained, and a theoretical basis is provided for construction method design of the step method construction.

Description

technical field [0001] The invention relates to the technical field of tunnels and underground engineering, in particular to a method for discriminating tunnel steps. Background technique [0002] During the construction of tunnels and underground projects, there are many construction methods. When the construction conditions of the project are poor or the excavation height of the project is too high, the one-time full-section excavation is likely to cause project instability. Therefore, in this case, it is often used Step method construction is used to ensure the safety of engineering construction, but there is a lack of more accurate judgment methods for step method construction in the prior art to determine the applicable situation of step method construction. [0003] The core content of the step method construction is to clarify the scientific and reasonable excavation height of each step, especially the excavation height of the upper step. The excavation height of the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/10
CPCG06F17/10Y02T90/00
Inventor 许崇帮张开顺王华牢刘志国李磊赵凡
Owner RES INST OF HIGHWAY MINIST OF TRANSPORT