大直径直眼掏槽钻爆施工技术的应用

本文从隧道爆破开挖点出发,重点介绍了隧道开挖中的钻爆设计,断面爆破各项参数及钻爆开挖的质量控制要点,以达到最佳的爆破效果。     

铜锣山隧道全断面开挖法钻爆设计

通过铜锣山隧道施工实例,就隧道全断面开挖钻爆设计进行了探析,分别对爆破参数选择、炮眼布置、爆破控制及监测、开挖爆破设计及验算等展开论述,通过此钻爆设计,解决了常规爆破存在的问题。     

光面爆破技术在洛阳村隧道Ⅲ级围岩应用总结

以洛阳村隧道Ⅲ级围岩段光面爆破工程为例,阐述了在中硬岩条件下隧道光面爆破材料选择及爆破参数的选取方法,重点介绍了全断面光面爆破及其钻爆设计流程,对实施程序进行了论述,并对爆破技术要求以及注意事项作了总结,以确保施工安全。     

光面爆破在隧道开挖中的应用

结合工程概况及其工程地质条件,对秦岭1号隧道开挖中的围岩钻爆设计过程及其钻爆施工技术进行了分析计算,介绍了钻爆作业的工艺流程,并对其光面爆破进行了评价,以供类似工程参考借鉴。     

复杂环境城市地铁大断面钻爆开挖施工技术研究

针对新建青岛地铁1号线海小区间地铁大断面钻爆开挖施工对周围构筑物和环境产生不利影响,通过现场勘探及理论分析,论述了控制爆破振速的可能性,通过优化爆破设计,提出合理的钻爆方案和参数,并经过爆破试验,验证了新方案的可靠性和安全性,达到了良好的钻爆施工效果。     

大断面瓦斯隧道钻爆开挖施工技术

针对新建简蒲高速大断面低瓦斯的二峨山隧道钻爆开挖施工难题,通过现场勘探及理论分析,论述了瓦斯涌出的可能性,并从爆破参数、安全验算及施工工艺等方面,提出了合理的爆破方案及参数,确保了瓦斯隧道钻爆开挖工程的质量及安全,达到了良好的爆破施工效果。     

微地震精细爆破技术在2扩4隧道开挖施工中的应用

本文依托于隧道扩挖工程实践介绍了微地震精细爆破技术的重要性。介绍了精细爆破的技术研究、爆破设计、器材选型、施工技术、施工管理以及爆破效果评价等内容。通过具体隧道扩挖工程实践,将爆破的计算理论、设计原则、钻爆参数以及减震措施等进行介绍,对具体工程进行监测和数值分析。最后本文还对应用的效果进行了总结。     

隧道爆破开挖数值分析研究

山岭隧道施工的常用方法是钻爆法,其关键技术是光面爆破。本文采用AUTODYN数值计算软件,对隧道IV级围岩全断面爆破开挖时的压应力场、爆破振动速度场进行了数值分析计算,根据数值分析计算结果,得出了相应的优化爆破设计的结论,从而达到隧道后期安全快速施工的目的,并为类似隧道工程爆破施工提供了较好的借鉴。     

桃花铺二号隧道光面爆破技术

介绍了桃花铺二号隧道施工中,根据不同断面、不同岩性,采用合理的钻爆设计,包括所采用的掏槽技术、光爆参数、炸药选择、装药结构等,使隧道的光面爆破取得了较好的效果。     

隧道水平岩层钻爆施工技术研究

结合具体工程实例,对隧道施工的地质情况进行了分析,探讨了影响柳林隧道光爆效果的因素,对隧道水平岩层钻爆施工技术进行了研究,提出了减小爆破震动的措施,积累了隧道围岩钻爆经验。     

Rogers pass tunnel—bore and blast

The 14.7-m Mt MacDonald Tunnel beneath Rogers Pass in Canada used both drill-and-blast and machine boring methods. A unique ventilation system provides for diesel operations. The design featured minimum construction support and an unreinforced poured concrete lining. The west heading was excavated in a single-stage drill-and-blast operation; the east heading used a TBM top heading with a drill-and-blast keyhole bench. The choice of methods was controlled by varying geology, which involved up to 1700 m rock cover. This paper evaluates construction performance and progress.     

Bore-and-blast techniques in different types of rock: Sweden's experience

The choice between drill-and-blast vs mechanical boring methods is often not obvious. Several factors may have a decisive influence on this choice-e.g. the geometry and length of the tunnel, site conditions and borability of the rock. Both the unconfined compression strength and the joint distance have a considerable influence on the net penetration rate. Site conditions, rock quality and water conditions influence the utilization of the tunnel boring machine. The drill-and-blast method is normally less sensitive to deviations from assumed ground conditions.     

New developments in drill-and-blast methods

Current drill-and-blast methods are described, and promising new methods currently under development, e.g. water-jet drilling, robotization, improvements in piston design, are discussed.     

Studies on the evolution process of rockbursts in deep tunnels

This paper focuses on the evolution processes of different types of rockbursts occurring in deep tunnels. A series of laboratory tests and in-situ monitoring in deep tunnels excavated by tunnel boring machine (TBM) and drill-and-blast (D&B) method have been conducted to understand the mechanisms and processes of the evolution of different types of rockbursts, including strain rockburst, strain-structure slip rockburst, immediate rockburst and time-delayed rockburst. Three different risk assessment methods are proposed to evaluate the intensity and potential failure depth of rockbursts. These methods can be applied before excavation and the results can be updated according to the real-time information during excavation. Two micro-seismicity based real-time warning systems have been established for predicting various intensities of rockbursts, such as slight, moderate, intensive and extremely intensive rockbursts. Meanwhile, the probability and intensity of the rockburst are also given. The strategy for excavation and support design has been suggested for various intensities of rockbursts before excavation. The strategy for dynamic control of the rockburst evolution process is also proposed according to the monitoring results. The methodology has been successfully applied to rockburst risk reduction for deep tunnels at Jinping II hydropower project. The results have illustrated the applicability of the proposed methodology and techniques concerning rockbursts.     

Blast-induced rock damage control in Fangchenggang nuclear power station,China

In the process of blasting excavation, stress wave propagation and gas expansion can basically induce damage to surrounding rocks, which is detrimental to rock mass integrity and engineering safety. In this case, evaluation and control of blast-induced effects are essential to the safety of nearby buildings and integrity of bedrock in blasting field. In Fangchenggang nuclear power station of China, the drill-and-blast method was employed for bedrock excavation. In order to reduce the blast-induced damage zone, the wave propagation and associated damage to rock mass should be carefully investigated. In this paper, the wave propagation regressively obtained from field monitoring data was presented based on empirical formula (e.g. Sadovsky formula). The relationship between the peak particle velocity (PPV) at a distance of 30 m away from the charge hole and charge per delay in blast design was derived. Meanwhile, the acoustic tests before and after blasting were conducted to determine the damage depth of rock mass. The charge per delay in blast design was then calibrated based on the blast-induced wave propagation regularity. The results showed that a satisfactory effect was achieved on blast-induced damage control of rock mass. This could be helpful to rock damage control in similar blasting projects.     

Tunnelling and underground construction in the twenty-first century

Future designers of underground structures will be able to take advantage of improved construction techniques in conceiving and designing their works. Conventional drill-and-blast and mechanical boring techniques will be competitive well into the twenty-first century. This paper examines different machines for mechanical excavation and discusses operating conditions and problems related to the use of rock boring machines. The author suggests a number of improvements that will be necessary for hard rock tunnel boring machines to achieve wider application; and describes a new design concept for TBMs that will allow them to cover a wide range of ground conditions. Technological achievements envisaged for the future include a “universal” hard rock TBM, the use of autopilot in excavating machines, and a significant increase in tunnelling advance rates.     

隧道钻爆法开挖的超欠挖控制

阐述了钻爆法隧道开挖时超欠挖产生的原因,分析了超欠挖对隧道施工成本和施工工序的影响,提出了控制超欠挖的主要途径,指出只有将施工技术管理、施工现场管理、施工资源配置等因素置于可控状态,才能取得最终的效益.     

Energy release process of surrounding rocks of deep tunnels with two excavation methods

Numerical analysis of the total energy release of surrounding rocks excavated by drill-and-blast(D&B) method and tunnel boring machine(TBM) method is presented in the paper.The stability of deep tunnels during excavation in terms of energy release is also discussed.The simulation results reveal that energy release during blasting excavation is a dynamic process.An intense dynamic effect is captured at large excavation footage.The magnitude of energy release during full-face excavation with D&B method is higher than that with TBM method under the same conditions.The energy release rate(ERR) and speed(ERS) also have similar trends.Therefore,the rockbursts in tunnels excavated by D&B method are frequently encountered and more intensive than those by TBM method.Since the space after tunnel face is occupied by the backup system of TBM,prevention and control of rockbursts are more difficult.Thus,rockbursts in tunnels excavated by TBM method with the same intensity are more harmful than those in tunnels by D&B method.Reducing tunneling rate of TBM seems to be a good means to decrease ERR and risk of rockburst.The rockbursts observed during excavation of headrace tunnels at Jinping II hydropower station in West China confirm the analytical results obtained in this paper.     

Dam foundation excavation techniques in China:A review

A protective layer(PL) is commonly reserved above foundation surface to protect the underlying rock mass during dam foundation excavation. In China, the PL of dam foundation is conventionally subdivided into two or three thin layers and excavated with the shallow-hole blasting method, even by pneumatic pick method in case of soft rock mass. The aforementioned layered excavation of the PL delays the construction of the whole project. After nearly 30-year practices, several safe and effcient methods for the PL excavation of dam foundation are gradually developed. They include shallow-hole bench blasting with cushion material(SBC) at the bottom of the hole, and horizontal smooth blasting(HSB). The PL is even cancelled on the condition that horizontal pre-split technique is employed during dam foundation excavation. This paper introduces the aforementioned two PL excavation methods(shallow-hole blasting and bench blasting) and horizontal pre-split technique of dam foundation without protective layer(HPP). The basic principles of blasting method, blasting geometry, charge structure, drill-and-blast parameters of typical projects are examined. Meanwhile, the merits and limitations of each method are compared. Engineering practices in China show that HSB is basically the optimal method for dam foundation PL excavation in terms of foundation damage control and rapid construction. Some new problems for dam foundation PL excavation arising, such as strong unloading and relaxation phenomenon that encountered in the gorge region of southwest China, are needed to be addressed; and the corresponding countermeasures are discussed as well.