GPR Survey For Subsurface Utility Mapping For Ahmedabad Metro Project

 

Scope of Work:

GPR survey execution for mapping underground utilities to prepare utility diversion plan at proposed metro station at Ahmedabad

Location:

Ahmendabad, Gujarat, India.

Client:

Larsen & Toubro Construction Ltd (L&T ECC)

Equipment:

GSSI SIR-3000 equipped with 200 MHz and 400 MHz antenna

Challenges:

Very busy road in city area. Data was collected in strips to avoid disturbance to traffic flow

Summary:

The GPR survey has been carried out in an area of about 50,000 m2 at proposed Shahpur Metro Sstation on Kasturba Gandhi Road between Delhi Darwaza and Gandhi Bridge in Ahmedabad. The scope of work include the mapping of possible underground utilities upto the depth of 8 m using non-destructive Ground Penetrating Radar technology. The purpose of the project is to locate all the chartered and uncharted utilities so as to prepare the utility diversion plan with the intention of acquiring a clear underground space for the metro station. Also, it intended to prevent the damage to the unobstructed utilities during the construction phase. Considering the client's requirements and the expected depth of the utilities, the area has been surveyed using 400 MHz and 200 MHz antenna mounted with SIR 3000 GPR system to cover the depth upto 7-8 m with fair resolution the data collected from the site has been processed appropriately using software package RADAN 7 and interpreted on the basis of the observed features. However, each and every profile was interpreted separately to obtain accurate location of any utility. The observed features of utilities are marked on the plan view in AutoCAD drawing with its depth information and were connected to obtain the alignment of the utility. In all, total 18 utilities were identified. Among 18 utilities, 10 were found to be uncharted whereas, eight utilities exactly matched the alignment of the chartered utilities mentioned in the drawing supplied by the client. In addition to it, overall around 74 manholes were located including catch pit, soak pit, etc.

 
GPRcase study-L&T
GPRcase study-L&T
GPRcase study-L&T
GPRcase study-L&T