Physical modelling of the hydro-mechanical properties of backfilled mine stopes

在大多数胶结膏体充填采矿中，空场通常分两种充填顺序进行充填：充填和残留充填。此外，充填系统和废石路障(WRB)的设计是经过一段时间的反复试验，或者基于往往高估了控制充填采场整体稳定性的应力状态的假设和模型。这项研究计划的独创性在于，这将是第一次同时进行充填采场和WRB的物理模型。因此，作为这项研究计划的一部分，将开展的工作将提供有关关键设计参数的知识，并回答工程师(矿业公司和工程咨询公司)提出的关键和反复出现的问题。在实验装置方面，我们将使用一个全新的1/15比例尺的采场物理模型(P2MS)和一个新设计的K0-固结硬化(K0-CH)槽。此外，我们将进行一维固结、单轴和三轴压缩、直接剪切测试、无损检测(NDT)和现场测量。提出了三个研究主题：主题1(T1)：充填采场的流体力学特性本主题将分为三个部分：T1.1部分(WRB水平压力的评估和预测)将解锁科学和技术锁，以开发一种准确和可靠地测量充填期间WRB水平压力的方法。我们将使用现场采场测量和P_2MS设备进行这次调查。第T1.2部分(充填过程中对塞子的需求评估)将调查在使用P2MS设备进行充填过程中对塞子的实际需求。第T1.3部分(通过实验室样品测试的原位回填机械强度的衡量)将使用K0-CH电池从实验室测试中衡量CPB的原位强度。以前的工作表明，原位CPB的强度有时与实验室规模的强度有很大不同。主题2(T2)：作为膏状回填保持结构的废石路障的尺寸确定为此主题，我们将使用仪表式P2MS设备来研究WRB的不稳定机制和破坏强度，并制定合理的WRB设计和施工指南。主题3(T3)：开发地下回填系统的设计辅助工具为此主题，我们将对所需的CPB强度进行概率分析，同时开发用于预测CPB强度的通用分析模型，以及用于CPB系统的免费设计软件包。该研究计划将资助2个博士项目和3个MASC项目。学生们将与他们在UQAT的同事以及矿业合作伙伴互动。通过这样做，它们也将成为技术转让过程的一部分，从而使加拿大受益于这项研究的结果。

In most mining with cemented paste backfill (CPB) operations, the open stopes are usually backfilled in two sequences: the plug fill and the residual fill. In addition, backfill systems and waste rock barricades (WRB) have been designed by trial and error over time or based on assumptions and models that tend to overestimate the stress regime that governs the overall stability of filled stopes. The originality of this research program is the fact that this will be the first time that a physical modeling of both a backfilled stope and WRB is done. Thus, the work that will be carried out as part of this research program will provide knowledge on key design parameters and answer crucial and recurring questions posed by engineers (mining companies and engineering consulting firms). In terms of experimental devices, we will use a brand new-built physical model of a mine stope at 1/15 scale (P2MS) and a new designed K0-Consolidation and Hardening (K0-CH) cell. In addition, we will perform 1D consolidation, uniaxial and triaxial compressions, direct shear testing, and non-destructive testing (NDT), and in situ measurements. Three research themes are proposed: Theme 1 (T1): Hydromechanical characterization of backfilled stopes This theme will be divided into three parts: Part T1.1 (Assessement and prediction of horizontal pressure on WRB) will lift the scientific and technical locks in order to develop a methodology for accurate and reliable measurements of the horizontal pressures on the WRB during filling. We will used in situ stope measurements and P2MS device for this investigation. Part T1.2 (Evaluation of the need for a plug during backfilling) will investigate the real need of a plug during backfilling using the P2MS device. Part T1.3 (Scaling of in situ backfill mechanical strength from lab specimens testing) will scale the in situ strength of CPB from laboratory tests using the K0-CH cell. Previous work has shown that the strength of in situ CPB is sometime significantly different from the one obtained at the lab scale. Theme 2 (T2): Dimensioning of waste rock barricades as paste backfill-retaining structures For this theme, we will use the instrumented P2MS device to investigate the instability mechanisms and the failure strength of a WRB as well as the development of a guide for rational WRB design and construction. Theme 3 (T3): Development of design assistance tools of underground backfill systems For this theme, we will perform a probabilistic analysis of the required CPB strength, in conjunction with the development of a generalized analytical model, for predicting the CPB strength, and a free design software package for CPB systems. A total of 2 PhD and 3 MASc projects will be supported by the research program. Students will interact with their colleagues at UQAT, as well as with mining partners. In doing so, they will also become part of the technology transfer process so that Canada benefits from the results of this reserach.