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Chapter 8
Push technology in the rail environment
Introduction (to in-situ testing in the rail environment)
| INTRODUCTION (TO IN-SITU TESTING IN THE RAIL ENVIRONMENT) 8.1 | |
| Testing on rail tracks is a challenging and difficult task. The work is mostly carried out at night and within short periods of time. Access to the sites and working areas are often difficult. Until recently, the majority of rail-site investigations have been dynamic probing and window sampling. The problem with these methods is that the required depths are not always reached and the information gained is limited. Cone penetration testing (CPT) offers a better solution for gaining quality site investigation. Speed Working on the railways during night requires speed. It will take about 40 minutes to carry out a 15 m CPT. In a 6-hour night possession, 4 to 5 tests to depths of 15 m can be carried out, including getting on and off the track (depending on the length between access point and CPT positions). CPTs are fast, and productivity is higher which counteracts their extra cost compared to dynamic probing. Quality CPTs offer high quality data in an environment where it is difficult to get it from other methods. The CPT takes measurements every centimetre of the cone resistance, sleeve friction and inclination of thrust rods; and the method is guaranteed to obtain deeper penetration than dynamic probing. All of the results are shown instantly on a computer screen and therefore decisions concerning the investigation can be taken directly on site. Versatility There are a number of different CPT rigs for different rail conditions. These are described later in this chapter, but as long as there is a reaction force and a power supply, cone penetration tests can be carried out almost anywhere. A standard CPT rig can use any of the special cones described in Chapter 4. The rail unit can also install instrumentation such as piezometers and inclinometers. | |