Route surveying is comprised of all survey operations required for design and construction of engineering works such as highways, pipelines, canals, or. Route aracer.mobi - Download as PDF File .pdf), Text File .txt) or read online. route aracer.mobi - Download as PDF File .pdf), Text File .txt) or read online.
|Language:||English, Spanish, Indonesian|
|Distribution:||Free* [*Registration needed]|
Route surveying pertains to the laying out of proposed corridors for Alignment data involved three different data types: survey, legal, and construction. Land surveying is basically an art and science of mapping and measuring land. Route Survey: Refers to those control, topographic, and construction surveys. Route surveying includes the field and office work required to plan, design, and lay out any “long and narrow” transportation facility. • Most of.
Based on the designed cable survey route, logistics and environmental parameters a route survey scope of work is prepared which is the basis of the survey plan. The shallow-water survey covers typically a m — m survey corridor where cable burial is proposed and which should be surveyed using a different range of sensors such as multibeam echo sounder , sub-bottom profiler , side-scan sonar and magnetometer.
There are also nearshore sections from 0 to approximately 3m that need to be surveyed by divers that collect video footage and probe sediment thickness where survey vessels cannot operate. The survey sensors used in deep water are like those for nearshore surveys but with different specifications. A burial assessment survey using CPTs and coring is also required for ground-truthing the geophysical interpretation and finalisation of the Burial Assessment Survey.
In deep water beyond the proposed water depth for burial a single line of multibeam echo sounder data is collected to full ocean depth providing survey swaths of 3 x water depth up to 10 kilometres wide. Besides the chosen survey instruments and techniques, timing is a third factor and should address the optimisation of the survey plan as well as contingency plans to avoid any operations downtime, especially when the survey vessel is required to work in very remote areas.
Survey timing is critical in areas affected by seasonal weather patterns, i.
To achieve an optimum plan, particularly for surveying the offshore and deepwater section, an accurate segmentation of the survey disciplines based on the weather and environmental parameters has to be conducted and scheduled in the Plan of Work. Shallow- water Considerations In addition to the weather and tidal behaviour of the coastal waters, the topography of the seabed sometimes makes the nearshore survey challenging. Achieving a full multibeam coverage of the shallow-water section results in a very tight line spacing design.
The multibeam survey is not efficient in depths less than 5 metres as shown in Figure 2.
Another challenge is observed when the coastal area has an immediate slope change and a very steep and narrow continental shelf, such as in remote pacific islands. In these cases, the survey cannot be undertaken in both directions and the equipment needs to be towed from nearshore to offshore or downslope to avoid collision with a rapidly shoaling seabed. This will result in additional transits and consequently increase in survey time Figure 3. Lagoon environments comprise shallow waters, irregular seabeds and narrow high-energy entrances Figure 4.
In extended lagoons, the restrictive bathymetry of the coast approaches may be too complex for the larger offshore survey vessels. Thus, an extended inshore or nearshore survey may be required, which introduces more costs and mobilisation risks for those sections of the survey.
This may be mitigated by having a daughter survey craft on the main survey vessel, but this requirement must be considered before arriving on site! Deepwater Considerations As water depths increase there are many parameters to take into consideration, for example, underwater currents affecting survey positional accuracy when operating deep tow sensors.
This is critical for subsea object detection and positioning.
In addition to the MBES bin size, speed affects subsea target detection. Usually, there is additional backscatter or side-scan sonar data to detect targets that may not be resolved in the bathymetric data alone. A side-scan sonar investigation conducted by EGS shows how the detection of a one cubic metre target is affected by speed and range. A 1 m3 metal object was deployed on the seabed prior to running a series of lines past the object using a Klein Side-scan Sonar at a constant offset but different ranges and speeds.
The results show that target recognition decreases as the speed and range increases. This experiment proves that especially in deeper water a survey speed of more than 3 to 3. To create detailed isopachs, the sub-bottom profiler SBP data needs to be of sufficient density with cross line correlation. High data density is obtained by running closely spaced lines over the entire corridor, while cross-correlation is obtained by running cross lines.
This is easily achievable during inshore surveys where typically 11 to 13 survey lines are required to get sufficient MBES coverage and when cross lines are required for correlation. However, it becomes problematic in deep waters when only 3 survey lines are required to achieve MBES data coverage and no cross lines are needed or specified allowing for objects to go potentially undetected.
This is usually driven by economics rather than the desires of the onboard survey team. To mitigate against this route engineering is as far as possible carried out along survey lines. Tow fish Considerations Speed not only affects the target detection but it also determines the depth of towed systems. As the water gets deeper or slopes increase, to keep the tow fish flying as close as possible to seabed, the vessel speed has to be kept constant and as slow as possible.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime. Route surveying. Upcoming SlideShare. Like this presentation?
Why not share! Embed Size px. Start on. Show related SlideShares at end. WordPress Shortcode. Prakash Kumar Sekar , Learning is a lifelong process Follow. Published in: Full Name Comment goes here. Are you sure you want to Yes No. Course In Brief: Additionally involves specialist study on CAD and associated technologies.
For Enquiries Contact: Hurry up. Bhuwan Bisht. Dihno Tobidihno. Abdulquadri Olakunle , Sam Rajput.