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 a;; pos-
sible 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 un-obstructed utilities during the con-
struction 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.
