煤礦軟巖巷道支護(hù)強(qiáng)度優(yōu)化外文文獻(xiàn)翻譯中英文翻譯

1、英文原文The optimal support intensity for coal mine roadway tunnels in soft rocksC. Wang* Mining Engineering Program, Western Australian School of Mines, PMB 22, Kalgoorlie WA6430, Australia1. IntroductionThe essence of underground roadway support is to provide the surrounding rocks of an underground ro

2、adway with assistance to help them achieve stress and strain equilibrium and ultimately stability of deformation.The approaches to this goal are either to reinforce the rock mass by rock bolting or injection(internal rock stabilization) or to provide the surrounding rocks with a support resistance w

3、ith a magnitude being described as the support intensity (external rock stabilization).When an underground roadway is located in soft rocks which are too soft to be reinforced by bolting and/or unsuitable for rock injection because of restraints imposed by either the rock mass impermeability or rock

4、 mass deterioration when water is encountered, external rock support, such as steel sets, therefore becomes the only option for the stability control of the roadway. Under this circumstance, the support intensity means a support force acting per unit surface area of the surrounding rocks of the road

5、way. In soft rock engineering practice, the design of a support pattern for a roadway in underground coal mining is normally based on rules of thumb. In most cases, heavy support measures are adopted to secure a successful roadway.Fig. 1(a) demonstrates the excellent condition of a sub-level roadway

6、 within soft rocks at an underground coal mine in north China, where an excessive capital cost was applied for the achievement of roadway stability. In some cases, such as a service roadway driven in soft rocks at the same mine (Fig. 1(b), insufficient support intensity was specified as a result of

7、a lack of relevant experience and design codes. Consequently, failure of the roadway stability was inevitable and an extra cost was incurred when the subsequent roadway repair or rehabilitation was undertaken.The critical issue in both cases lies in the determination of an optimal support intensity

8、which is the function of the geometry and dimension of a roadway and its geotechnical conditions including rock mass properties, stress conditions and hydrological status.Physical modelling using simulated materials based on the theory of similarity provides a direct perceptional methodology for min

9、ing geomechanics study 1-6.Using simulated materials of the same composition to construct a roadway and its soft surrounding rocks, applying a certain magnitude of simulated support intensity to the surface of a roadway under simulated stress conditions, the three-dimensional physical modelling meth

10、od depicted in this Note emonstrates a quantitative solution for strategic design of roadway support concerned with soft rocks. A relation between the support intensity and deformation of the surrounding rocks of a roadway has been established after a series of simulation tests had been conducted. A

11、 discussion on the optimal support intensity for a roadway in soft rocks is also given.Fig. 1. Examples of successful and unsuccessful support of underground roadways within soft rocks: (a) Good condition of a sublevel roadway, (b) Unsuccessful support of a service roadway.2. Features of the three-d

12、imensional physical modellingA physical modelling study of the interaction between support intensity and roadway deformation was carried out using the three dimension physical modelling system (see Fig. 2) at the Central Laboratory of Rock Mechanics and Ground Control, China University of Mining and

13、 Technology. Features of this system are described in the following sub-sections.Hih pnesMift liLtnifcii iipcf Jitcd h)xlruulk vlwutTv l(< iibinlairing ciwiVueI h>s»dswaler、叫中用l“c、iuLln:rU，=、：clliFig. 2.Three-dimensional loaded physical modelling system at the CentralEleUfiuNy coninltxl 帖

14、dnkuh4 7曲|哨 hxj xppUi” 人心，to IhvSinevt rnc.i*urcnic»L <4 fhc"UmnntinF rmL、N' thwRcjI 3D 仲限"trjJTicLaboratory of Rock Mechanics and Ground Control, China University of Mining andTechnology.2.1. Size of the physical modelThe effective size of a physical model is 1000 mm wide, 100

15、0 mm high and 200 mm thick.2.2. Three dimensional active loading capabilitySix flatjacks are used to apply loads to the six sides of the physical model in the form of a rectangular prism. Each flatjack was designed to cover the full area of one of the six sides and be capable of applying a pressure

16、of up to 10 MPa on to the surface of the simulated rock mass. This means that the flatjacks are capable of applying an active load of up to 1000 tonnes and 200 tonnes simultaneously on the front and back facets, the top and bottom, and the two side facets of a model, respectively.2.3. Long-term cont

17、inuous loading capabilityA high-pressure, nitrogen-operated, hydraulic pressure stabilising unit was employed to maintain a consistent magnitude of load applied to the model so that the physical modelling test is able to last continuously for weeks, months or even years without interruption. This fe

18、ature ensures that the study of the long-term rheological behaviour of soft rocks can be carried out.3. Physical modelling testsPhysical modelling of an underground roadway/ tunnel within soft rocks with a hydrostatic stress condition was carried out. The same simulated materials were repeatedly use

19、d six times to construct six physical models. Each roadway model was provided with a different magnitude of support intensity.3.1. Geotechnical conditions for the prototype and the modelling scaleA specified underground roadway within soft rocks was assumed to be the prototype for the modelling stud

20、y. Detailed geotechnical conditions of the roadway and its surrounding rocks are:circular roadway with a diameter (D) of 4.5 m and cross-sectional area of 16 m 2;UCS (Rc ) of the surrounding rock was 20 MPa;bulk density of the surrounding rock was 2500 kg/m3;depth of the roadway location was 500 m b

21、elow surface;rock mass stress (s0 ) was 12.5 MPa in all directions;support intensity(pa) to be applied to the roadway was 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6MPa, respectively.The geotechnical modelling scale (Cl ) determined was 1 : 25. The bulk density (gm ) of the simulated rock mass materials was 160

22、0 kg/m3.Therefore, all the related simulation constants are:similarity constant for bulk density: Cg ? 1600/2500=0.64;similarity constant for strength: Cs ? ClCg ? 0:256;similarity constant for load: CF ? CgC1 ? 4:096 10?5 ;similarity constant for time: Ct ? C l:5 ? 0:2:Geotechnical conditions of th

23、e simulated rock massand roadway were derived from those of the prototype rock mass as presented below:strength of the simulated rock mass: Rm=RcCs=0.512;diameter of the simulated roadway: Dm=DCl=180 mm;load intensity on the facets of the model: pm=s0Cs=0.32 MPa;Simulated support intensity: pam=paCs

24、=0.00256, 0.00516, 0.00768, 0.01024, 0.0128 and 0.01536 MPa; respectively.3.2. Realization of support intensity in physical modellingDue to the restraints of the small dimensions of the model roadway on the simulation of support structure, the support pattern and structure were unable to be simulate

25、d. Instead, an equivalent support intensity was simulated and applied to the surface of the surroundingrock of the model roadway. A Static Water Support and Deformation Measurement System (SWSDMS) was designed specially. Fig. 3 illustrates the SWSDMS being installed in the model roadway. The mechani

26、sm of SWSDMS is to use 4 separate water capsules to apply a support intensity to the surface of the roadway roof, two side walls and floor. Four rubber tubes, each of which was linked to a water capsule and filled with water, were used to generate a water pressure at the capsule/rock interface and m

27、easure it through the water level reading.A certain constant simulated support intensity was achieved by applying a certain height of static water pressure. A change to support intensity could be made by changing the water height in the rubber tube. The volume change of each of the four water capsul

28、es was measured at the due time by collecting and weighing the water overflow. The volume of water coming from each of the four water capsules was used to calculate the radial deformation of roadway surrounding rock, i.e., roof subsidence, wall-to-wall closure and floor heave. The proposed simulated

29、 supportintensities, i.e., Pam ? 0:00256, 0.00516, 0.00768, 0.01024, 0.0128 and 0.01536 MPa, were achieved by adjusting the static water level to 256, 516, 768, 1024, 1280 and 1536 mm high, respectively.TulWh hir 汕“中皿血¥ tnEo tfte capMiles and italic 削仃 prt大、uw 加比打市口塞iixiSwtiiunding 門小 i*f 屁On$m

30、jl hmndar) of ihcFig. 3. Static Water Support and Deformation Measurement System (SWSDMS)being accommodated in a roadway model in the real 3-D loaded physical modelling system.3.3. Construction of physical modelThe compositions and properties of materials to be used for the construction of physical

31、models were studied prior to the physical model construction. Given the significant rheological deformation of roadways excavated in soft rock, sand and paraffin wax were chosen for the simulated soft rock. The properties of a series of sand/paraffin wax mixtures were studied in laboratory and are p

32、resented in Table 1.Table 1 Compositions and properties of sand/paraffin wax mixturesRecipe-'Sand : paraffin wax (by weight)*Uniaxial compressive streneth (MPa)Sample 1Sample 2Sample 3Average -100:20.0330.0300.0290.0307100:30.05540.0530.0530.053&100:40.08640.08420.08520,0853舉100:5,wWwVmMmW*0

33、.100.1070.1120.106+j100:60.1280.13040.1240.1275J100:70.13860.13800.14240.13974According to the geotechnical conditionsof the prototyperock mass and themodelscale, a mixture of sand/paraffin wax of 100 : 3 was selected to construct the rock massmodel. The procedures involved in the model construction

34、 include cold mixing of the sand and paraffin wax, oven heating the sand/wax mixture and constructing the physical model using the hot sand/wax mixture.3.4. Process of physical modellingThe real process of an underground roadway excavation, support installation and deformation of the surrounding roc

35、ks with time was simulated in the laboratory physical modelling. After the model had cooled down, prestressing the model, excavation of the roadway under pressure, installation of the SWSDMS device and measurement of the roadway deformation were carried out step by step. The whole process of modelli

36、ng was strictly conducted according to the time similarity constant. Each physical modelling step lasted for 10-25 days in the laboratory, which were equivalent to a real time period of 50-125 days approximately.4. Relations between support intensity and roadway deformationComparable results of the

37、six physical modelling tests conducted with the identical materials and geotechnical conditions revealed the significance of the support intensity in underground roadway/tunnel support.4.1. Effect of support intensity on the deformation characteristics of a roadwayThe deformation characteristics of

38、an identical roadway with different support intensity is graphically presented in Fig. 4(a) and (b). It can be seen that the influence of support intensity on the deformation characteristics is significant. With a support intensity of 0.1 MPa, the roadway experienced a large eformation for a period

39、of 118 days after the roadway excavation and the provision of support intensity. During this period, an average of 828 mm deformation was accumulated. Following this period, the wall-to-wall closure and網(wǎng) 4mTiu ifkf nxd wty cowMICO-M煦麗T-roof-to-floor convergence stayed steady at a level of 4.4 mm/day

40、. By contrast, when a support intensity of 0.6 MPa was provided to the identical roadway, its post-excavation deformation merely lasted for 36 days with an accumulative closure/convergence of 40 mm, followed by a rheological deformation of 0.08 mm/day, which was continuously reducing withFig. 4 Defo

41、rmation of roadway with a series of support intensities:(a) Deformation of roadway with time, (b) Deformation rate of roadway with time.time. The comparison shows that the deformation magnitude of the latter was only 4.8% that of the former.A negative exponential relation between the deformation rat

42、e and support intensity canalso be deduced from the curve of deformation rate vs. support intensity presented in Fig. 5 and be mathematically expressed as: v ? 0:023pa2:4 :where v is the rheological deformation rate of the surrounding rock of a roadway in mm/day, pa is the support intensity in MPa p

43、rovided to the surrounding rock.Supporting vtensity (M冏Fig. 5 elations between rheological deformation rate and support intensity of aroadway in soft rocks.4.2. Optimal support intensity for a roadway in soft rocksRequirements on the control of roadway deformation depend on the usage and servicelife

44、 of the roadway. It is known that a zero deformation rate is impossible practically to target in supporting a roadway in soft rocks. A wise approach is to exercise a design principle that the roadway deformation is allowed to take place to a degree within an acceptable limit. Physical modelling resu

45、lts indicated that an increase of support intensity from 0.1 to 0.5 MPa can markedly reduce the deformation rate of the surrounding rocks. A further increase of support intensity from 0.5 to 0.6 MPa, however, did not bring about as much reduction of deformation rate as that created by the support in

46、tensity increase of from 0.1 to 0.2 MPa or from 0.3 to 0.4 MPa. This means that a reasonable range of support intensity exists and an increase of support intensity can be rewarded with a significant reduction of roadway deformation if the actual support intensity is within this range.Further increas

47、es of support intensity can only cause less reduction of roadway deformation. Therefore, if both technical and economical considerations are taken into account, a support intensity of from 0.3 to 0.5 MPa would be appropriate for most temporary tunnels such as roadways in underground coal mining. Wit

48、h this support intensity, the rheological deformation rate of the surrounding rocks can be controlled within a range of from 0.1 to 0.4 mm/day, with which an ordinary temporary roadway can be maintained safely for years to one decade.5. ConclusionsThe three- dimensional physical modelling method pro

49、vides a nceptual apcooach to quantitative design ' of roadway support associated with soft rocks. With lack of knowledge of the constitutive relations, especially for the rheological mechanisms, in rock engineering practice, the modelling results could serve as a foundation on which a scientific

50、 design of underground roadway/tunnel support is developed, particularly when a large amount of rock mass deformation is concerned.The experimental study conducted with a series of support intensities revealed that a reasonable support intensity exists. Its value depends on the geotechnical and geom

51、etric conditions of the underground roadway/tunnel concerned and the requirements applied by the roadway/tunnel safe use specifications and the roadway/tunnel service life span. The results indicate that a support intensity of 0.3 to 0.5 MPa can securely control the closure rate for the conditions t

52、ested within a magnitude of 0.1 to 0.4 mm/day for a medium size underground roadway/tunnel driven in soft rocks of around 20 MPa at a depth of about 500 m below surface.References1 Internal Research Report. Study on the technology of large deformation control for roadways within soft rocks. China Un

53、iversity of Mining and Technology, 1995 in Chinese.2 Wang C. Study on the supporting mechanism and technology for roadways in soft rocks. PhD thesis, China University of Mining and Technology, 1995 in Chinese.3 Internal reference (1993). Properties of simulated materials for physical geomechanical m

54、odelling. The Central Laboratory of Rock Mechanics and Ground Control, China University of Mining and Technology in Chinese.4 Lin Y . Simulated materials and simulation for physical modelling. Publishing House of China Metallurgy Industry, Beijing, China,1986 in Chinese.5 Duro ve J, Hatala J, Maras

55、M, Hroncova E. Support' bsseesign physicalmodelling. Proceedings of the International Conference of Geotechnical Engineering of Hard Soils Soft Rocks. Rotterdam: Balkema, 1993.6 Singh R, Singh TN. Investigation into the behaviour of a support system and roof strata during sub-level caving of a t

56、hick coal seam. Int J Geotech Geol. Engng.1999;17:21-35.中文譯文煤礦軟巖巷道支護(hù)強(qiáng)度優(yōu)化C. Wang采礦工程專業(yè)，西澳礦業(yè)學(xué)校，港口及航運(yùn)局 22卡爾古利 WA6430 ,澳大利亞1引言地下巷道支護(hù)的實(shí)質(zhì)是給巷道圍巖提供支撐以實(shí)現(xiàn)應(yīng)力應(yīng)變平衡，并最終使變形穩(wěn)定。為達(dá)到這一目標(biāo)，需通過錨桿支護(hù)加固巖體或注漿(內(nèi)部巖石穩(wěn)定) 或?yàn)閲鷰r提供被描述為支撐強(qiáng)度的具有有一定數(shù)量級(jí)的支撐阻力(外部巖石穩(wěn) 定)。當(dāng)?shù)叵孪锏捞幱谒绍泿r石中，巖石過于松軟以致錨桿加固或不適合注漿加周。這是因?yàn)橛龅剿畷r(shí)巖體滲透性或巖體惡化施加的限制。因此，外部巖石支護(hù)如鋼棚支

57、護(hù)，成為了巷道穩(wěn)定控制的唯一選擇。在這種情況下，支護(hù)強(qiáng)度是指單 位巷道圍巖表面積的支撐力。在軟巖工程實(shí)踐中，地下煤礦巷道支護(hù)模式設(shè)計(jì)通 常是基于經(jīng)驗(yàn)法則。在大多數(shù)情況下，采用支護(hù)強(qiáng)度大的支護(hù)措施，確保巷道穩(wěn) 定。圖1 (a)展示了在中國北方一煤礦為實(shí)現(xiàn)巷道穩(wěn)定投入過多資金成本的煤 礦井下軟巖分段巷道的良好條件。 在某些情況下，例如在同一煤礦軟巖中開掘的 服務(wù)巷道(如圖1 (b),支撐力不足被指定為缺乏相關(guān)經(jīng)驗(yàn)和設(shè)計(jì)規(guī)范所致。 因此，巷道失穩(wěn)是必然的。在隨后進(jìn)行巷道維修或重建時(shí)，又需支出額外的費(fèi)用。這兩種情況的關(guān)鍵問題在于最佳的支護(hù)強(qiáng)度， 與巷道的斷面形狀和巖土工程 條件，包括巖性，應(yīng)力條件和水

58、文狀況呈函數(shù)關(guān)系。基于相似理論的相似材料的物理模擬為礦山地質(zhì)力學(xué)研究提供了直接感知 的方法。1-6利用組成相同的相似材料來模擬巷道及周圍軟巖， 模擬應(yīng)力條件下施加一定 的支護(hù)強(qiáng)度到巷道表面。在這份說明中描述的三維實(shí)體建模方法， 展示了軟巖巷 道支護(hù)戰(zhàn)略設(shè)計(jì)方面定量計(jì)算的方案。通過一系列相似實(shí)驗(yàn)的結(jié)果，支護(hù)強(qiáng)度和 巷道圍巖變形間的關(guān)系建立。關(guān)于軟巖巷道最佳支護(hù)強(qiáng)度的討論也 由此展開。圖1地下軟巖巷道支護(hù)成功和失敗的例子a分段巷道的良好條件b服務(wù)巷道支護(hù)失效2.三維實(shí)體模型的特征在中國礦業(yè)大學(xué)巖土力學(xué)與地面控制中心實(shí)驗(yàn)室進(jìn)行的關(guān)于支護(hù)強(qiáng)度和巷道圍巖變形間關(guān)系的物理模擬研究采用了三維實(shí)體模型系統(tǒng)（見圖2）。該系統(tǒng)的特征描述如下：液壓控制臺(tái)操作高壓 氮?dú)獗３重?fù)載一致都水支撐和變龍測(cè)量系統(tǒng)電控液壓站向 物理模型加載巷道圍巖應(yīng)力測(cè)量真實(shí)三維實(shí)體模型推架圖2中國礦業(yè)大學(xué)巖土力學(xué)與地面控制中心實(shí)驗(yàn)室三維加載實(shí)體模型系統(tǒng)2.1 實(shí)體