Abstract
As lots of underground mines have been exploited in the past decades, many stope instability and surface subsidence problems are appeared in the underground mines, while the cemented paste backfill (CPB) technology has been applied for more than 40 years, and it can solve these problems. As it is shown that the effect of backfilling is mainly affected by the mechanical properties of the CPB, and there are lots of factors which can influence the strength of the CPB, but the coupled effects of curing conditions has not been reported. In this research, the coupled effects of curing conditions are importantly considered, and the uniaxial compressive strength (UCS) is adopted as the important evaluation index of CPB, then the evolution law of the UCS for CPB are analyzed, also the mathematical strength model of CPB is established. The findings suggest that the relationship between the UCS of CPB and curing stress develops the function of quadratic polynomial with one variable, while the UCS of the CPB shows the power function as the curing temperature increases. Moreover, the established mathematical strength model is verified on the basis of laboratory experiments, the error between the measured UCS and the prediction UCS is less than 15%. It shows that the established strength model of the CPB by considering the curing conditions can predict the UCS very well, it has great significance for the safety design of CPB.
Highlights
As more and more mines have been excavated, many voids are produced in the underground mines, a lot of tailings are disposed in the tailing dam, there are huge challenges we are facing, such as the surface subsidence, stope instability and safety of the tailing dams [1,2]
Based on the above analysis, it is evident that the mathematical strength model of cemented paste backfill (CPB) can be obtained by the Formula (5), and it contains the influencing factors of curing conditions, the parameters relation to the formula are clear
According to the above analysis, the histogram of UCSmeasured/UCSpredicted based on the mathematical strength model are shown in Figure 8, it shows that the means and the median are all close to 1, which indicates that the predicted uniaxial compressive strength (UCS) of CPB is consistent with the experiment UCS
Summary
As more and more mines have been excavated, many voids are produced in the underground mines, a lot of tailings are disposed in the tailing dam, there are huge challenges we are facing, such as the surface subsidence, stope instability and safety of the tailing dams [1,2]. In terms of the UCS for CPB, many studies had been done by the scholars, Andrew and Fall’s [11,12] study indicated that the UCS was significantly influenced by the curing temperature, because the hydration reaction rate of the cement was firstly affected. Wang and Yilmaz [18,19,20] had studied the relationship between the cement types, cement content and mechanical properties of CPB, indicating that the hydration reaction rate and UCS of the CPB were mostly affect by them. The majority of the above studies are concentrated on one influencing factor, while there are few studies about the coupled effects of curing conditions on the mechanical properties of CPB. UUCCSS TTeessttss AAss iitt iisskknnoowwnnththaat tththeeUUCCS Sisiosnoenoef othf ethmeaminaiinnfliuneflnuceinngciinngdeinxdesextoesretfolercetfltehcet mtheemcheacnhiacnalicparloppreorpteierstieosf oCfPCBP, Bth, tehreefroefroer, ea,fateftrearlalltlhtheespspeceicmimenenssaarreeccuurreeddffoorr tthhee rreeqquuiirreedd ccuurriinnggttiimmeess,,ththeennalalltlhtehespsepceimcimenesnasrearteestteesdtetdo otobtoabintatihne tUhCe SUoCfSthoefCthPeB.CBPeBfo. rBeetfhoeretetshtse, itteisstsn,eitedisendeteoddeidsptoosdeisapllotsheeaslpl ethciemsepnesc.imtheentso.pthaentdopboatntodmbootfttohme sopfetchiemsepnecsihmouenldsbheouthlde pbleatinhesuprlfaaincestuorfbaecpeatorablleelp, aarlsaollethl,easlstaontdhaersdtasnizdeaorfdtshiezespoefctihmeesnpiesc5im0 emnmisa5n0dm1m00amnmd 1f0o0r immttessamdtcihinfaoigmnremietitsasecdrahidaainnomdepetihteseedarigdtaohontpod.btIhetndeaiitgnthohitstoh.sbeItntuUadtiChnyiS,tsthohsetfeuUCWdPCyDBS, ,tWohthfe-5eCW0cPoDsBenW,rttvrh-oo5el0cacosocnecnrtutrvrroooallccuyaoncnoicatfurxiortialaiculsypn±rioae0fxs.2isita%uilrs.pe±rt0ee.ss2st%iunr.ge
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