Rock mass dynamic response to extraction

岩体对开采的动态响应

• 批准号: RGPIN-2015-04851
• 负责人: Mitri, Hani
• 金额: $ 1.6万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=590059
• 关键词: Rock; mass; dynamic; response; extraction

Many civil and mining engineering projects require that the rock be excavated to meet underground space design requirements, or for the purpose of extracting ore material from the earth crust. Shafts, tunnels and mining stopes are only some of the numerous examples of rock excavations widely used in civil and mining engineering projects. The process of rock extraction disturbs the equilibrium of the host rock in that the in-situ rock pressure decreases at some locations and increases at others around the excavation. This may cause instability problems leading to the fall of loose rock blocks in case of low rock pressure. In the case of high post-extraction rock pressure, the excavation may collapse violently, especially when the rock is strong and brittle. This is known as rockburst or strainburst. It is invariably accompanied by the occurrence of microseismic activities in the host rock. Microseismicity occurs as the host rock is re-adjusting itself to the sudden rise in rock pressure following extraction. Such effects are known as the dynamic response of rock to extraction – the topic of this research. In an effort to avoid disasters due to violent rock failure or rockburst, networks of microseismic sensors are installed underground to monitor the response of the rock to extraction activities on a 24/7 basis. When the data is analyzed, it is possible to identify the time, intensity and location of microseismic events and estimate the speed of rock shaking, known as peak particle velocity, and the seismic energy released from the host rock as a result of an extraction process. Much research was done in the past few decades to help advance the knowledge and understanding of the rock response to extraction. It is now possible to develop sophisticated numerical models capable of simulating complex shapes of rock excavations found in geologically complex environments, as well as the in situ rock pressure, and the planned extraction sequence. However, to date, the majority of these efforts focused on simulating the extraction process in the simpler-to-model “static” conditions, i.e. a process that is not accompanied by seismic response. This deficiency is dealt with in this research as it has created a gap between the developed static models and reality, i.e. dynamic response of the rock exhibiting burst and microseismicity. The applicant has begun in recent years to address this modelling deficiency, by developing algorithms depicting the dynamic response of rock to extraction, capable of computing post-extraction pressure, peak particle velocity and seismic energy released. This research will focus on the development and verification of algorithms for the characterization of the dynamic rock response to extraction. Subsequently, it will take the developed algorithms to real-life applications for validation in Canadian mines where tremors at great depth are of much concern to the safety of the mine operators.

许多土木工程和采矿工程项目要求挖掘岩石以满足地下空间设计要求，或用于从地壳中提取矿物质。竖井、隧道和采矿场只是在土木工程和采矿工程中广泛使用的众多岩石挖掘例子中的一部分。开挖过程破坏了围岩的平衡，在开挖过程中，围岩压力在某些位置减小，而在其他位置增大。这可能会造成失稳问题，导致松散岩块在低矿压情况下坍塌。在回采后围岩压力较大的情况下，开挖可能会剧烈坍塌，特别是在岩石坚硬和脆性的情况下。这就是众所周知的岩爆或应变爆破。它总是伴随着围岩中微震活动的发生。微震活动发生时，围岩正在重新调整，以适应开采后岩石压力的突然上升。这种效应被称为岩石对开采的动态响应--这是本研究的主题。为了避免剧烈岩石破裂或岩爆造成的灾难，地下安装了微地震传感器网络，以全天候监测岩石对开采活动的反应。当对数据进行分析时，就有可能确定微震事件的时间、强度和位置，并估计岩石震动的速度，即所谓的粒子峰值速度，以及由于提取过程而从宿主岩石释放的地震能量。在过去的几十年里，人们进行了大量的研究，以帮助提高对岩石对开采的响应的认识和理解。现在有可能开发复杂的数值模型，能够模拟在地质复杂环境中发现的复杂岩石挖掘的复杂形状，以及现场岩石压力和计划的开采顺序。然而，到目前为止，这些努力大多侧重于在模型更简单的“静态”条件下模拟开采过程，即不伴随地震响应的过程。这一不足在本研究中得到了解决，因为它造成了所开发的静态模型与实际之间的差距，即表现出突发性和微震活动的岩石的动态响应。申请人近年来已开始解决这一建模缺陷，开发了描述岩石对提取的动态响应的算法，能够计算提取后的压力、粒子峰值速度和释放的地震能量。这项研究将集中在开发和验证算法，以表征动态岩石对开采的响应。随后，它将把开发的算法带到加拿大煤矿的实际应用中进行验证，在那里，深度震动非常关系到煤矿操作员的安全。