1、 本科毕业设计 英文翻译 题 目 加拿大岩爆支护手册 学 院 水 利 水 电 学 院 专 业 水 利 水 电 工 程 学生姓名 尹 刚 学 号 0943062172 年级 09 级 指导教师 张 茹 二 一三年六月三日四川大学本科毕业设计 英文翻译 Canadian Rockburst Support Handbook 1 2.1Introduction Explicit analysis of each potential rockburst-damage mechanism and the interaction between the rockmass and the support s
2、ystem are complex tasks. This chapter provides a summary of the key items found in this handbook such that the practitioner is provided with guidance for support selection in burst-prone ground without undertaking all of the analytical steps necessary to complete a detailed design. For this summary
3、chapter, details of the analysis procedures have been omitted, but they are described in subsequent chapters. Rockburst damage refers to damage that occurs around an excavation in a sudden or violent manner and is associated with a seismic event. Rockburst damage may not necessarily result in ejecti
4、on of rock into the excavation, especially if the excavation is well supported. The damage mechanisms associated with different types of rockbursts vary from situation to situation (Kaiser 1993； Ortlepp and Stacey 1940). The first step in dealing with support selection for burst-prone conditions is
5、to estimate the type of damage mechanism involved and the likely severity of the resulting damage. Also it is useful to understand the conditions that lead to or trigger a rockburst. 2.2 What causes rockbursts? For the purposes of hazard assessment and support design we distinguish between rockburst
6、s that are triggered by remote seismic sources and rockbursts that are “self-initiated”. For self-initiated rockbursts, the location of the damage and the seismic event are the same. 2.2.1 Self-initiated rockbursts Self-initiated rockbursts occur when the stresses near the boundary of an excavation
7、exceed the rockmass strength, and failure proceeds in an unstable or violent manner. The stresses generally increase as a result of nearby mining. In addition, the rockmass strength may degrade with time or with loss of confinement, leading to sudden failure. In either case the rockmass strength-to-
8、stress ratio reaches unity and the rock fails. The failure process is sudden and violent if the stored strain energy in the rockmass is not dissipated in a gradual manner. This occurs when the stiffness of the loading system, i.e., the mine stiffness, is softer than the unloading stiffness of the vo
9、lume of failing rock (Jaeger and Cook 1969； Brady and Brown 1993). 四川大学本科毕业设计 英文翻译 Canadian Rockburst Support Handbook 2 Another form of self-initiated rockburst is caused by a loss of structural stability. One example is the sudden buckling of a column or slab of rock. Structural instability usuall
10、y leads to sudden failure but the conditions leading to failure are dependent on geometric considerations rather than the strength of the rock. 2.2.2 Remotely triggered rockbursts Rockbursts triggered by remote, relatively large magnitude seismic events (e.g., fault slip) are a common occurrence in
11、some hard rock mines, particularly during the later stages of the mines life and where faults intersect stopes or large mined-out areas and sill pillars. A remote seismic event within a rockmass may create sufficiently high vibrations, and hence dynamic stresses,near an underground opening to initia
12、te rockburst damage. The incoming seismic wave may lead to fracturing of rock near an underground opening, or lead to structural instability (buckling), or directly provide sufficient energy to eject rock due to seismic energy transfer, rockburst hazard assessment involves determining the peak parti
13、cle velocities induced in the rock around underground openings close to the seismic source, i.e., generally within a few hundred metres (Chapter 5). However, meta-stable structures such as dykes and pillars may react to seismic events at larger distances ( 1000m). 2.2.3 Influence of mining stage The nature of the mining-induced seismic activity and the associated rockbursts occurring in a mine usually change throughout the mines life span. In some Canadian mines, significant
