Civil engineering

Rock excavation in urban development and civil engineering is getting more and more complicated. The reason for this is the increased urbanization of cities. Cities expand but they also get denser. This means that construction increasingly takes place close to surrounding buildings. Regulations demand safe operation and that noise and dust levels are to be kept at a minimum.

 

At Epiroc. we always strive to be one step ahead when it comes to noise reduction, dust suppression and safety features. All this without compromising the core values; drilling performance, wide hole range, large coverage area and well balanced drill rigs.


Dictionary

Some useful industry terms


Civil engineering and urban development applications

A few examples
  • Trenching
  • Residential foundation drilling
  • Industrial foundation drilling
  • Infrastructure
    • Road construction
    • Pipeline construction
    • Hydroelectric dams
  • Shaft sinking – drill- and blast
  • Boulder blasting
  • Underground service operations
  • Small tunneling
  • Selective bolting
  • Utility installation
  • De-watering
  • Grouting

Road construction

Meeting special aesthetic criteria is often required for highway development projects that cross land with special scenic or recreational characteristics. However, the topographic setting of most highway projects means that it is impossible to replicate exactly natural landforms in engineered rock cuts. Natural landforms almost always involve flatter slopes than can economically be designed for highway embankments, and even where the natural landscape is sufficiently rugged, the natural rock slopes are generally much more degraded than is desired for the sides of highway cuttings. In consequence, it is difficult to make cut slopes look ‘natural’.

Urban blasting

Drilling in urban environments presents a number of challenges, of which noise reduction is key. Blasting constraints include keeping ground vibration to a minimum, and preventing both air blast and flyrock. For this reason, drilling and blasting on urban sites is much more tightly controlled than elsewhere, with impact minimization becoming increasingly important. Indeed, in some situations, drilling and blasting is no longer an option and in extreme conditions, technologies such as excavator-mounted rock cutters, diamond wire machines, hydraulic hammers and splitters may be the only way to achieve the required excavation. There has been a growing trend for non-blast rock excavation in urban areas. In competent rock formations, the most common method is large size hydraulic splitters that are driven and attached to an excavator. A large number of drill holes are required in patterns from 0.2x0.2 m up to 0.8x08 m depending on hole size and power of the splitter device. To reduce the vibration from blasting the sensitive foundation or structure can be separated from the rock by a deep cut close to the structure. The cut is done by diamond wire machines.

Noise reduction

Our Noise Reduction Kit is the perfect equipment for operation in urban areas. Noise Reduction Kit reduces noise levels by as much as 10 dB, making it perfect for job sites with noise regulations. The design is lightweight and sturdy with hydraulically operated hatches. Since noise levels can affect people in and around the job site, you need to be aware of possible regulations. With the Noise Reduction Kit, you are fully prepared to work in an urban environment – without disturbing your surroundings

 

Here are some of the additional benefits:

 

Longer working hours

The Noise Reduction Kit minimizes the exposure of sound while drilling and it's perfect for places with noise regulations. So, if working hours are limited due to noise, the Noise Reduction Kit may result in longer working hours as the disturbance decreases. Add to that – it can be remotely controlled. This means higher productivity and greater time efficiency.

 

Easy to monitor

The lightweight and sturdy design makes it a reliable partner for an enhanced working environment. Thanks to the hydraulic hatches the operator can have total control over the drilling process. It's designed by several modules, which makes it easy to replace parts if needed.

 

Working environment

Since the Noise Reduction Kit can be controlled remotely from a distance, the ergonomic situation for the operator is enhanced. Add to that, the feed is encapsulated, which contributes to lower dust- and oil levels in the air. In summary, the kit improves the working environment for both personnel and citizens around the job site.

 

Hear the difference with and without Noise Reduction Kit

The types of drill rigs favored by construction drilling contractors, typically tophammer drill rigs, are inherently noisier than for example a DTH rig. One reason for this is that the rock drill is mounted on the feed instead of Down-The-Hole. Nonetheless, the need for noise reduction on urban construction sites can be addressed by equipping the rig with a noise reduction kit, which Epiroc has been offering since 2005. An updated version, is available for use on rigs such as the SmartROC T35 and SmartROC T40, cutting the noise output from these machines from 127 dB(A) unsilenced to 115 dB(A), and making it possible to hold a conversation next to the operating drill rig. A more sophisticated Rig Control System (RCS) also play its part in cutting noise, with the engines on the current generation of rigs responding to second-by-second requirements, rather than running at full speed all the time. 

 

Air blast is a particular phenomenon that is invariably caused by the detonation of unconfined – or inadequately confined – explosives. The resulting pressure wave is manifested as noise and in damage to surrounding properties; even low overpressure levels can break windows, while high energy waves can cause structural damage. Risk minimization is achieved by using careful blasting procedures, and by ensuring that all explosives are confined with an adequate amount of stemming or cover material in place before detonation.

 

Ground vibrations result from blasting, with the aim of a good blast design being to minimize the peak particle acceleration associated with the propagation of shock waves through the ground. It is quite common for specialized blasting consultants to be involved to assist the contractor with vibration control and the design of drill patterns, as well as to carry out a thorough survey of adjacent structures before the drilling and blasting can begin. The key to minimizing ground vibrations is to optimize the blasting sequence in terms of the amount of explosives being detonated at one time, through the use of a properly designed detonator delay program. In addition, the drill hole diameter should be kept as small as possible, normally in the range 30–50 mm. To eliminate the risk of fly rock, blasts can be covered with inert material such as sand, or by using heavy mats made of timber, rubber or tires, cut into sections and bound together with steel wire. Weighing around 1 tonne each, these mats absorb energy and prevent loose rock from being dispersed, while their structure allows the gases produced by the blast to flow through.

FlexiROC T15 R

Reach and stability

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Trenching

Trenches are often excavated for the installation of gas, oil, water and sewage pipelines, as well as for power cables. Trench blasting is often defined as rounds with a width of less than 4 m, meaning that the width of the round can be considerably smaller than its length. By its nature, a trench blast is more constricted than a normal open-pit blast, so has a higher explosives consumption per cubic meter of blasted rock. The drill hole diameter used is normally smaller than in other construction or quarrying applications. This provides for better distribution of the explosive in the rock and avoids excessive overbreak outside the theoretical contour. As a rule of thumb, the hole diameter should be one sixtieth of the width of the trench, so if the width is 2.0 m, a 33 mm hole diameter would be suitable. Two methods are used for trench blasting: traditional and smooth wall. In traditional trench blasting, the middle hole/holes are placed in front of the edge holes, and all the holes are charged with the same amount of explosives. In smooth wall trench blasting, all the holes in each row are in line. The middle hole or holes are quite heavily charged, while the edge holes have light charges.

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