Calculation method for evaluating stability of tunnel face-footage section of inclined shaft
A calculation method evaluates the stability of the inclined shaft face-footage section by analyzing geometric and angular relationships, velocity, and energy dissipation to ensure safe construction by determining stability safety factors.
Patent Information
- Application Number
- CN202311410411.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-27
- Publication Date
- 2024-12-27
AI Technical Summary
Existing methods lack a theoretical analysis for evaluating the stability of the inclined shaft face-footage section, which affects construction safety, particularly in tunnels with deeper burial depth and larger cross-sections.
A calculation method is developed to evaluate the stability of the inclined shaft face-footage section by determining geometric and angular relationships, velocity of failure blocks, surrounding rock gravity, and internal energy dissipation, culminating in a stability safety factor to assess safety.
The method provides a basis for safe construction by determining stability safety factors, allowing for appropriate reinforcement measures based on excavation height and footage, ensuring the stability and safety of the inclined shaft face-footage section.
Smart Images
Figure CN119203289A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of inclined shaft construction, and in particular relates to a calculation method for evaluating the stability of an inclined shaft face-footage section. Background Art
[0002] With the improvement of tunnel construction technology in my country, tunnels are currently developing towards a trend of deeper burial depth, longer length and larger cross-section. In order to speed up the construction progress, auxiliary channels such as inclined shafts are often used to increase the working surface. For example, the Yuelongmen Tunnel of the Chenglan Railway crosses the Longmen Mountain Range in western Sichuan. It is a double-hole tunnel with a total length of 19,981 m for the left line and 20,042 m for the right line. It has a single-side uphill slope of 17.8‰ and a maximum burial depth of 1,450 m. Three inclined shafts are used as auxiliary channels to speed up the construction progress. During the construction of the inclined shaft, each excavation will affect the stability of the face; and there is an interaction between the stability of the footage section and the stability of the face. The instability of the footage section will affect the face, and the instability of the face may extend to the footage section. Therefore, the stability research of the inclined shaft face-footing section has important theoretical significance and engineering application value.
[0003] At present, there are few studies on the stability of the inclined shaft face-footage section. The few existing literatures or patents use numerical simulation to analyze the stability of the inclined shaft face under different inclined shaft inclination angles and different inclined shaft face forms, but fail to provide a theoretical analysis method. Summary of the invention
[0004] The purpose of the present invention is to provide a calculation method for evaluating the stability of the inclined shaft face-footage section. The present invention can determine whether the inclined shaft face-footage section meets the safety requirements, and then determine the stability safety factor of the inclined shaft at different excavation heights and different excavation footages, thereby providing a basis for the safe construction of the inclined shaft.
[0005] The calculation method for evaluating the stability of the inclined shaft face-footage section of the present invention comprises the following steps in order: (1) Geometric and angular relationship between the failure surface dimensions of the inclined shaft face and the footage section: ; ; ; ; ; ; ; ; ; Where: L AE is the length between point A and point E; D is the excavation height of the inclined shaft; L AF is the length between point A and point F; L en Excavation footage for inclined shaft; L OA is the length between point O and point A; L OB is the length between point O and point B; φ is the internal friction angle of surrounding rock; a is the inclination angle of the inclined well; a 1 is the angle between side OA and side AB; a 2 is the angle between side OB and side AB; a 3 is the angle between side AE and side FE; a 4 is the angle between side FE and side AF; a 5 is the angle between side AE and side AF; (2) Determine the velocity relationship of each failure block in the tunnel face-depth section: ; ; ; ; ; Where: v 1 is the velocity of the block OAB; v 0 is the speed of destroying the block AFE; v 0,1 is the relative velocity of block AFE relative to block OAB; a 6 For speed v 0 and speed v 0,1 The angle of a 7 For speed v 1 and speed v 0,1 The angle of a 8 For speed v 0 and speedv 1 The angle of (3) The power of the surrounding rock gravity external force, which includes the following steps: (I) Based on the above calculation of the relationship between the side lengths of the blocks, the area of each block is obtained: ; ; Where: S OAB is the area of block OAB; S AFE is the area of the block AFE; (II) The power of the external force of surrounding rock gravity is the product of the gravity of each block and the vertical component of the velocity. Based on the area and velocity of the block obtained above, we can get: ; Where: W γ is the external force power of surrounding rock gravity; γ is the weight of surrounding rock; (4) The power dissipated by the surrounding rock internal energy is: ; Where: E D is the energy dissipation power within the surrounding rock; c is the cohesion of surrounding rock; (5) The stability safety factor is: ; Where: Fos is the stability safety factor; (6) Determine whether the inclined shaft face-footage section is stable and safe: like , then the inclined shaft face-footage section is stable and the construction is safe; like , then the inclined shaft face-footage section is unstable and the construction is unsafe; Where: [Fos] is the allowable stability safety factor.
[0006] Compared with the prior art and research methods, the present invention has the following advantages: At present, there are few studies on the stability of the inclined shaft face-footage section. The few existing literatures or patents use numerical simulation to analyze the stability of the face under different inclined shaft inclination angles and different inclined shaft face forms, and adopt specific engineering reinforcement measures, but fail to provide a theoretical analysis method.
[0007] The present invention provides a calculation method for evaluating the stability of the inclined shaft face-footage section; based on this, it can be evaluated whether the face-footage section is stable and safe; and then the stability safety factor under different inclined shaft excavation heights and different excavation footages can be determined, thereby providing a basis for the safe construction of the inclined shaft. The method of the present invention can also be applied to the stability evaluation of the face-footage section when the inclined shaft auxiliary channel is used for the construction of mining tunnels, hydraulic tunnels, etc., and the analysis of pre-reinforcement measures. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 It is a schematic diagram of the principle of the method of the present invention.
[0009] Figure 2 It is a velocity relationship diagram of each failure block in the inclined shaft face-feed section.
[0010] Figure 3 It is a stability safety factor diagram under different excavation heights and different excavation footages of an embodiment of the present invention.
[0011] In the figure, 1 is the inclined shaft excavation face; 2 is the inclined shaft excavation section; 3 is the inclined shaft lining section; L en Excavation footage for inclined shaft; D is the excavation height of the inclined shaft; a is the inclination angle of the inclined well; φ is the internal friction angle of surrounding rock; a 1 is the angle between side OA and side AB; a 2 is the angle between side OB and side AB; a 3 is the angle between side AE and side FE; a 4 is the angle between side FE and side AF; a 5 is the angle between side AE and side AF; v 1 is the velocity of the block OAB; v 0 is the speed of destroying the block AFE; v 0,1 is the relative velocity of block AFE relative to block OAB; a 6 For speed v 0 and speed v 0,1 The angle of a 7 For speed v 1 and speed v 0,1 The angle of a8 For speed v 0 and speed v 1 Angle. DETAILED DESCRIPTION
[0012] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.
[0013] See also Figure 1 , is a schematic diagram of the principle of the calculation method for evaluating the stability of the inclined shaft face-footage section of the present invention.
[0014] First, according to the engineering overview of the inclined shaft and the surrounding rock grade, relevant parameters are obtained, such as the surrounding rock cohesion c and the surrounding rock internal friction angle. φ , Inclined shaft angle a， Inclined shaft excavation height D, inclined shaft excavation footage L en wait.
[0015] The specific calculation steps are as follows: Step 1: The geometric and angular relationship between the failure surface dimensions of the inclined shaft face and the footage section: ; ; ; ; ; ; ; ; ; Where: L AE is the length between point A and point E; D is the excavation height of the inclined shaft; L AF is the length between point A and point F; L en Excavation footage for inclined shaft; L OA is the length between point O and point A; L OB is the length between point O and point B; φ is the internal friction angle of surrounding rock; a is the inclination angle of the inclined well; a 1 is the angle between side OA and side AB; a 2is the angle between side OB and side AB; a 3 is the angle between side AE and side FE; a 4 is the angle between side FE and side AF; a 5 is the angle between side AE and side AF; Step 2: Determine the velocity relationship of each failure block in the tunnel face-depth section: ; ; ; ; ; Where: v 1 is the velocity of the block OAB; v 0 is the speed of destroying the block AFE; v 0,1 is the relative velocity of block AFE relative to block OAB; a 6 For speed v 0 and speed v 0,1 The angle of a 7 For speed v 1 and speed v 0,1 The angle of a 8 For speed v 0 and speed v 1 The angle of Step 3: The power of the surrounding rock gravity external force, which includes the following steps: (I) Based on the above calculation of the relationship between the side lengths of the blocks, the area of each block is obtained: ; ; Where: S OAB is the area of block OAB; S AFE is the area of the block AFE; (II) The power of the external force of surrounding rock gravity is the product of the gravity of each block and the vertical component of the velocity. Based on the area and velocity of the block obtained above, we can get: ; Where: W γ is the external force power of surrounding rock gravity; γ is the weight of surrounding rock; Step 4: The power dissipated by the surrounding rock internal energy is: ; Where: E D is the energy dissipation power within the surrounding rock; c is the cohesion of surrounding rock; Step 5: Stable safety factor: ; Where: Fos is the stability safety factor; Step 6: Determine whether the inclined shaft face-footage section is stable and safe: like , then the inclined shaft face-footage section is stable and the construction is safe; like , then the inclined shaft face-footage section is unstable and the construction is unsafe; Where: [Fos] is the allowable stability safety factor.
[0016] The above equation is an explicit equation. c is 40kPa, the internal friction angle of surrounding rock φ is 15°, and the surrounding rock mass γ is 25kN / m 3 , Inclined shaft angle a is 10°, the inclined shaft excavation height D is 5m, and the inclined shaft excavation footage L en The inclined shaft is 3m, and the allowable safety factor [Fos] is 1.2. According to the above steps, the stable safety factor Fos can be obtained as 1.50, which is greater than [Fos]=1.2, so the inclined shaft face-footage section is safe.
[0017] Then, by changing the different inclined shaft excavation heights D and different excavation and footage Len, the corresponding stable safety factor can be obtained, such as Figure 3 shown.
[0018] It can be seen from the figure that: with the increase of excavation height and excavation footage, the safety factor of inclined shaft stability decreases. Therefore, in order to improve the stability of the inclined shaft face-footage section, measures such as lowering the excavation height of the inclined shaft or reducing the length of excavation footage at one time can be taken.
Claims
1. A calculation method for evaluating the stability of the inclined shaft face-feed section, characterized in that The steps include the following sequence: (1) Geometric and angular relationship between the failure surface dimensions of the inclined shaft face and the footage section: ； ； ； ； ； ； ； ； ； Where: L AE is the length between point A and point E; D is the excavation height of the inclined shaft; L AF is the length between point A and point F; L en Excavation footage for inclined shaft; L OA is the length between point O and point A; L OB is the length between point O and point B; φ is the internal friction angle of surrounding rock; a is the inclination angle of the inclined well; a 1 is the angle between side OA and side AB; a 2 is the angle between side OB and side AB; a 3 is the angle between side AE and side FE; a 4 is the angle between side FE and side AF; a 5 is the angle between side AE and side AF; (2) Determine the velocity relationship of each failure block in the tunnel face-depth section: ； ； ； ； ； Where: v 1 is the velocity of the block OAB; v 0 is the speed of destroying the block AFE; v 0,1 is the relative velocity of block AFE relative to block OAB; a 6 for speed v 0 and speed v 0,1 The angle of a 7 for speed v 1 and speed v 0,1 The angle of a 8 for speed v 0 and speed v Angle of 1; (3) The power of the surrounding rock gravity external force, which includes the following steps: (I) Based on the above calculation of the relationship between the side lengths of the blocks, the area of each block is obtained: ； ； Where: S OAB is the area of block OAB; S AFE is the area of the block AFE; (II) The power of the external force of surrounding rock gravity is the product of the gravity of each block and the vertical component of the velocity. Based on the area and velocity of the block obtained above, we can get: ； Where: W γ is the external force power of surrounding rock gravity; γ is the weight of surrounding rock; (4) The power dissipated by the surrounding rock internal energy is: ； Where: E D is the energy dissipation power within the surrounding rock; c is the cohesion of surrounding rock; (5) The stability safety factor is: ； Where: Fos is the stability safety factor; (6) Determine whether the inclined shaft face-footage section is stable and safe: like , then the inclined shaft face-footage section is stable and the construction is safe; like , then the inclined shaft face-footage section is unstable and the construction is unsafe; Where: [Fos] is the allowable stability safety factor.