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

在大多数采用胶结充填（CPB）作业的采矿中，空场通常以两种顺序进行充填：充填塞和残留充填。此外，回填系统和废石挡墙（WRB）的设计是通过长期试错或基于假设和模型进行的，这些假设和模型往往高估了控制充填采场整体稳定性的应力状态。这项研究计划的独创性在于，这将是第一次对回填采场和WRB进行物理建模。 因此，作为该研究计划的一部分，将开展的工作将提供关键设计参数的知识，并回答工程师（采矿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比例的采场物理模型（P2 MS）和一个新设计的K 0-固结和硬化（K 0-CH）单元。此外，我们还将进行一维固结、单轴和三轴压缩、直接剪切试验、无损检测（NDT）和现场测量。提出了三个研究主题： 专题1（T1）：回填采场的流体力学特性 该主题将分为三个部分：第T1.1部分（水RB水平压力的评估和预测）将解除科学和技术锁，以开发一种方法，用于准确和可靠地测量水RB在填充期间的水平压力。我们将使用现场采场测量和P2 MS设备进行本次调查。第T1.2部分（在使用P2 MS器械进行调试期间对插头需求的评价）将调查在使用P2 MS器械进行调试期间对插头的真实的需求。第T1.3部分（根据实验室样本测试的原位回填机械强度的缩放）将使用K 0-CH单元根据实验室测试缩放CPB的原位强度。先前的工作表明，原位CPB的强度有时与在实验室规模下获得的强度显著不同。 主题2（T2）：将废石挡墙作为膏体回填挡土结构 对于这个主题，我们将使用仪器化的P2 MS设备来研究WRB的不稳定机制和失效强度，以及制定合理的WRB设计和施工指南。 主题3（T3）：地下回填系统设计辅助工具的开发 对于这个主题，我们将进行所需的CPB强度的概率分析，结合开发一个通用的分析模型，用于预测CPB强度，以及CPB系统的免费设计软件包。 该研究计划将支持2个博士和3个硕士项目。学生将与UQAT的同事以及采矿合作伙伴进行互动。在这样做的过程中，他们也将成为技术转让过程的一部分，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.