ABSTRACT
This paper documents the successful application of explosive compaction technology for the densification of granular soils using case history data from a number of sites. The data include densification projects in urban areas, for dam foundations and for offshore structures. The paper provides general background information on the theory of explosive compaction of soils, design considerations, and the densification results achieved.

An offshoot technology using the sequential detonation of explosives is also described to evaluate in situ the seismic liquefaction potential of soil. The method is based on the use of a number of blast pulses to generate shearing strains within a test volume of soil, having similar strain magnitudes (or cyclic shear stress ratios) as a design level earthquake.

Keywords: Explosive compaction; blast densification; liquefaction testing.

ABSTRACT
This paper discusses the challenges encountered in drilling and blasting of a small diameter shaft underneath a parking garage in historic Gastown, Vancouver, BC. This project involved drilling in a restricted headroom area, blasting in a confined space environment, and excavating using a novel vacuum technique. The 1.2m x 1.2 m x 8.5m deep shaft was required for installation of a hydraulic piston for a show lift. The project called for very accurate drilling through inter-bedded sandstone and siltstone within the water table. Development of a unique blast design was required for blast vibration control on a historic structure located just 15.8 meters away. The shaft was successfully completed without damage to any of the surrounding structures.

ABSTRACT
This paper describes techniques used in the demolition of reinforced concrete structures, problems encountered, and practical solutions to many of these problems. The authors draw upon the experience and international reputation gained by Pacific Blasting & Demolition Ltd. over a period of close to 50 years in the successful completion of construction blasting works. The paper also discusses the design and fabrication of specialized drilling equipment to tackle unique challenges. Special requirements unique to demolition blasting of underwater structures are also discussed.

ABSTRACT
This paper presents data gathered during a comprehensive study on the impact of improvements to fragmentation in a major Limestone quarrying operation. The full impacts of gains in fragmentation are tracked through the mucking, crushing, and grinding phases of the operation.

The target of this study was to attain a D-90 or 90% passing size of 0.20 meters from the current D-90 fragmentation level for production blasts of 0.60 meters, or in other words, basically increase fragmentation three fold. This was accomplished through a change from 200mm blast holes on a 6.0 x 7.0 meter pattern to 102mm blast holes on a 3.0 x 3.5 meter equilateral triangle based staggered pattern. Extensive use was made of high speed photography, WipFrag Fragmentation Analysis, production studies, power consumption studies, and micro fissure analysis, to track the impact of gains in fragmentation.

ABSTRACT
This paper is a summary of the work carried out by an international team of specialists in the successful explosive compaction of the sand fill core of the Molikpaq offshore oil production structure. The sand fill core is an essential element for the stability of the structure. The sand core must resist liquefaction forces caused by heavy wave action, ice loading, and earthquakes. Explosive compaction methods were used to improve the stability of 220,000 cubic meters of coarse dredged sand placed in the core area.

This project was challenging for a number of reasons. It was performed offshore in Russia, seven kilometers off the East Coast of Sakhalin Island. Logistics were a challenge, not just in getting the men and materials to the site, but also working with restricted headroom inside an operating oil drilling platform. This project called for the use of specialty explosives, strict blast vibration controls requiring a complex sequential blast design, and use of custom designed drill rigs. As Russian equivalent explosives were not available, the project involved getting approval for use of North American explosives in Russia, and use of a combined Russian - Canadian blasting crew. The blasting program was carried out successfully, meeting the required densification target in a safe, effective manner, with no damage to the structure.

ABSTRACT
This paper covers the successful application of explosive compaction technology for the densification of the foundation soils for the seismic upgrade of the Seymour Falls Dam, Vancouver, BC. The original earth fill embankment constructed during 1958-1961, was upgraded in 2004-2007 to withstand the effects of a maximum credible earthquake.

This paper provides general background information on the theory of the explosive compaction of soils, history of use, geology of the site, project constraints, explosives selection, blast designs, instrumentation used, problems encountered and solutions implemented, and the results achieved.

The project involved the use of electronic detonators and cap sensitive emulsion explosives subjected to an extreme overpressure environment. The project is an excellent example of what can be achieved through the use of “state of the art” explosives technology coupled with the latest instrumentation. The project demanded the close cooperation of a team of drillers, blasters and engineers to accomplish a difficult goal under very demanding conditions.

ABSTRACT
This paper discusses the successful blasting demolition of three bridge piers for construction of the new 4-lane Stave River Bridge. The bridge is located at the junction of the Stave and Fraser Rivers, approximately fifty kilometres east of Vancouver, BC. The new westbound span had been constructed within 1 meter of the older span to be demolished. The new span carried a 150mm diameter gas line and overhead power lines, telephone lines, and the nearby CP Rail bridge carrying a fibre optic line all represented additional challenges. As the Stave River is a major salmon spawning stream, great care with control of overpressures was required. Tight blast vibration control was also required to protect the new bridge structure. The Pacific Group was involved in jacking and removal of the old steel span structure as well as demolition of the bridge piers.

ABSTRACT
This paper describes rock slope remediation performed along America’s first Superhighway, the Pennsylvania Turnpike and in particular, the specialized drilling equipment designed and built by Pacific Blasting to complete this work. This 8-month project was performed on an existing rock cut slope within the Bedford Narrows, a gap formed by the Juniata River through Evitts Mountain. These rocks are in the folded Juniata and Tuscarora Formations within the Valley and Ridge Province and strike northeast with near vertical to slightly overturned bedding.

Over three hundred 50-foot (15.24m), 1¼” rock dowels were pattern bolted on the rock face. The specialized drilling equipment, designed and fabricated specifically for this project, that enabled safe, efficient drilling and dowel installation throughout the project area is highlighted. This system was also successfully employed at Seattle, Washington for drilling blast holes at the Kingdome Implosion.

Public safety and unimpeded traffic flow throughout the project area of this busy highway was of prime importance. Protection from falling rock was provided with an in-house modification of a proven rock fall containment net first tried by Washington State Department of Transportation. The protection system allowed for safe vehicular travel on the Pennsylvania Turnpike while rock excavation and scaling activities were performed. This protection system and specialized rock excavation techniques employed are also discussed.

Two additional projects, the Kingdome Implosion in Seattle and the Kootenay Pass rock slope stabilization project also utilized specialized drilling systems. The drilling systems required for these projects are highlighted.