外文翻譯--破碎軟巖巷道圍巖的變形特征（英文）

1、Received 24 April 2008; accepted 10 September 2008 Project 40773040 supported by the National Basic Research Program of China Corresponding author. Tel: +86-15032009909; E-mail address: jinxi77@sohu.com Deformation char

2、acteristics of surrounding rock of broken and soft rock roadway WANG Jin-xi1, LIN Ming-yue1, TIAN Duan-xin2, ZHAO Cun-liang1 1Key Laboratory of Resource Survey and Research of Hebei Province, Hebei University of Enginee

3、ring,Handan, Hebei 056038, China 2The Bureau of Land and Resources of Wu’an City, Wu’an, Hebei 056300, ChinaAbstract: A similar material model and a numerical simulation were constructed and are described herein. The def

4、ormation and failure of surrounding rock of broken and soft roadway are studied by using these models. The deformation of the roof and floor, the relative deformation of the two sides and the deformation of the deep su

5、rrounding rock are predicted using the model. Measurements in a working mine are compared to the results of the models. The results show that the surrounding rock shows clear rheological features under high stress cond

6、itions. Deformation is unequally distributed across the whole section. The surrounding rock exhibited three deformation stages: displacement caused by stress concentration, rheological displacement after the digging ef

7、fects had stabilized and displacement caused by supporting pressure of the roadway. Floor heave was serious, accounting for 65% of the total deformation of the roof and floor. Floor heave is the main reason for failure

8、of the surrounding rock. The reasons for deformation of the surrounding rock are discussed based on the similar material and numerical simulations. Keywords: soft rock roadway; broken surrounding rock; similarity simula

9、tion; numerical simulation; deformation characteristics 1 Introduction As the depth of underground mining and railway tunnel construction increases failure problems in the soft rock get increasing attention from depar

10、tments of scientific research and construction[1]. In the 1970’s, Salamon M D et al. proposed the energy supporting theory. They thought that the supporting structure and surrounding rock of a roadway interact with e

11、ach other and deformed together. The supporting structure absorbs part of the energy that the surrounding rock releases in the deformation stage. However, the total energy does not change. Yu X F et al. proposed that

12、 the failure of surrounding rock of roadway was the result of stresses exceeding the strength limits of the rock. Landslide changes the axis ratio of the roadway, which leads to stress redistribution, i.e. a reduction

13、 in high stress and an increase in low stress to reach a stable balance. The roadway would be steady when the stress is equally distributed: Its final shape is elliptic. Dong F T et al. proposed the theory of the br

14、oken rock zone around roadway. His basic viewpo- int was that the broken rock zone of a bare roadway is close to zero. Although elasto-plastic deformation of surrounding rock of the roadway occurs, the rock needs no

15、supporting. Deformation increases with an increase in the broken rock zone. And the bigger the deformation is the more difficult support is. Therefore, the purpose of support is to prevent harmful deforma- tion in the

16、 broken rock zone around roadway[1]. The distribution of the plastic zone and an asymmetrical control mechanism of the surrounding roadway rock using weak structures were discussed in Reference [9]. Meanwhile, the st

17、ability of surrounding rocks of roadways was studied from various points of view. Owing to the lack of research related to soft rock engineering or large deformations in soft rock, most soft rock roadways are current

18、ly maintained just after being dug. They are difficult to support, which is a disadvantage for safe production in the mine. This seriously influences the economic benefits of the enterprise. Therefore, the deformatio

19、n and support of soft rock roadway is one of the key problems of coal mining. Developing safe production requires better information[2]. The deformation of a broken soft rock roadway is simulated by a similar-materia

20、l experi- ment and by a numerical model based on geological conditions and supporting parameters of a refit roadway. The results are described in this paper. The deformation and failure characteristics of a broken s

21、oft rock roadway were analyzed based on the measured results.Mining Science and Technology 19 (2009) 0205–0209MINING SCIENCE AND TECHNOLOGYwww.elsevier.com/locate/jcumt WANG Jin-xi et al Deformation charac

22、teristics of surrounding rock of broken and soft rock roadway 207Table 2 Similarity parameters Geometrical ratio l CDensity ratioγ COutside force ratio f CStrength ratio σ CTime ratiot C20 1.5 12000 30 4.47 The

23、moving peak stress method is used for simulating dynamic pressure mining. The size of the model is 2.0 m×2.0 m×0.1 m. The load is applied by an iron mass and a jack. The circumferential displace- ment of the

24、 roadway, which includes displacements of the roof, floor and the two sidewalls, is measured throughout loading. The relationship between the deformation of the surrounding rocks and the load, as well as the relatio

25、nship between deformation and displacement of the surrounding rock, was measured. Results from the model are shown in Fig. 3. ???????????????? ? ? ? ? ? ? ? ? ?? ?? ?? ??????????????????????????????????????????????????

26、??????????????????????? ?? ?? ?? ?? ?? ?????????????????????????????(a) Deformation of surrounding rock and loading (b) Deformation and depth of the surrounding rocks Fig. 3 Relationship between de

27、formation and surrounding rock and loading and depth Fig. 3 shows that under a low load (less than class 7) the roof sinking is rapid compared to the floor and sides. This is because the roof surface was exposed when

28、the roadway was excavated. The roof surface and concrete shotcrete clearly deform toward the roadway space. The deformation of the floor was bigger than the convergent deformation of the sidewalls. Under high loads t

29、he speed of deformation of the floor and the sidewalls rapidly increased; these deformations exceeded the convergence of the roof. These deformations progressed from asymmetry to equality and then back to asymmetry a

30、gain on the anchored segments of the sidewalls and roof, in the supporting model, when the roadway was loaded with an extremely high load. The anchored segments separate from deeper surrounding rock under this high l

31、oad[6–8]. Floor heave occurred in the model but did not appear homogeneously at every deformation stage, although it was obvious under a high load. 3.2 Numerical simulations A section of rock 40 m long perpendicular

32、to the strike and 40 m high were simulated. This model included a total of 12 strata in the model. The roadway is 5.0 m×4.1 m in size and the pull-out length every time is 1 m. The material mechanical propertie

33、s used in the model are shown in Table 3.Table 3 Mechanical properties of materials used in the numerical model Elasticity (GPa) Poisson’s ratio Bonding strength (MPa) Friction angle (tan) Density (kN/m3) Tensile streng

34、th (MPa)Fine-sandstone ? 0.2 0.8 1.42 26.0 6.9 Sandy mudstone 7.5 0.15 0.4 1.15 22.0 3.1 Siltstone 1.3 0.2 0.7 1.25 22.4 1.5 Shale 8 0.35 0.3 1.3 23.1 2.4 Mudstone 7.5 0.35 0.3 1.15 22.0 1.8

35、6 Coal 7.5 0.1 0.1 0.5 18 3.6 The roadway is an underground roadway with broken surrounding rock. The Moore-Coulomb criterion[9] was used for numerically simulating the linear broken surface corresponding to the

36、 shear failure: s 1 3 2 f N c N ? ? σ σ = ? +(1) where (1 sin )(1 sin ) N? ? ? = + ? , 1 σ is the maximum principal stress, 3 σ is the minimum principal stress, ? is the friction angle and c is cohesive force. Th

37、e bottom of the model is fixed. The sides and the top of the model are force field boundaries with the values: v H 2.5 MPa σ σ = =(2) The model is meshed into 38520 geological units, 41937 nodes and 2094 supporting uni

38、ts. The displace- ment and stress contours are drawn in Fig. 4. The surrounding rock of the roof and the shallow floor are a low stress region in the primary digging time; the stress is lower than that of the sidewal

39、ls. The regions at the base angles of the roadway and below the belt line of the sidewalls are in a concentrated stress region where the stress is 10 times that in the roof. The stress in the surrounding rock is comp