Ground drilling for linear structures — manholes, markings, noise barriers

The linear construction differs from the flat design in four respects, which directly determine the choice of technology and machinery.

Hundreds of points in the regular season. The spacing between the base points is usually in the order of units of meters and repeats along the entire length of the route. Therefore, what matters is not the performance at one point, but the time for that point multiplied by the number of points — and the ability of the machine to move smoothly without re-arming.

Work in operation. The route is usually not closed. Work is being carried out on one lane of traffic, under temporary traffic signs, often at night. Every day when the base is not sufficient to accommodate traffic, the restriction period is extended.

Protection zones of engineering networks. Along the roads there are cable lines, water pipes, gas pipes and fiber optics. Interference with the protective zone has its own regime — and the point base is located in a different position than the continuous trench.

Variable longitudinal profile. The route passes through a ditch, a notch, and a transition between the overgrown terrain and compacted roadside vegetation. The soil profile changes along its length without the project changing.

Funfairs and landfills. In concrete work, there needs to be space for the material, equipment, and wet processes along the entire route. That is exactly what is most expensive and most difficult to implement in linear construction.

This is the most sensitive part of linear structures and is always handled in the same way:

1. Designation of networks by administrators. Before starting work, a statement and the designation of all the networks in the route are requested. Without the designation, work cannot proceed.
2. Verification probe at critical points. In places where the line of points intersects the designated grid, a manually-drilled probe is performed or the point is moved according to the project.
3. DTH drill through hard casing. Where there is over a load-bearing layer of asphalt or compacted substrate, a DTH pre-drill is used — controlled and without causing any damage to the surrounding area.
4. Continuous recording of depth and moment. The unexpected increase in torque at an unusual depth is an immediate signal to stop. The recording also serves as evidence for the network administrator.

 

The specific working conditions in the protection zone are determined by the network operator’s statement and the relevant regulations for the specific type of operation. The scope and depth of the intervention must be agreed upon before the work begins.

1. Project preparation and statements by network operators. The static engineer determines the type and length of the screw and the spacing of the points according to the load on the structure. All engineering networks in the route will be specified and marked.
2. Geotechnical base along the length of the route. Because the profile changes along the route, the load-bearing capacity is verified at the representative points of each section, not just at one location. Eurocode 7.
3. Temporary traffic signs and impounding. Establishing a workplace in accordance with the approved transport engineering measure, usually in one lane or in the night window.
4. Gradual turning along the route. The machine moves along the route, marking each point. When laying down on the side, no need to rotate between points. The moment and depth are recorded for each point.
5. Checking the alignment and position. Verification of deviation from the projected position and orientation at each point, protocolly.
6. Reinforcement of the structure and release of the section. The joint, bar or panel is installed immediately after drilling. The finished section is ready for use without waiting for curing.