How to know about geotechnical planing at site or field investigations and purpose in civil engineering technology?

 

2          FIELD INVESTIGATIONS

 

2.1       PLANNING

 

In order to evaluate the foundation conditions at the site, Boreholes of variable depths were planned at the locations duly specified and directed by Mr. Raja Waheed, in the light of project requirements. The soil sampling was extracted from all Boreholes and preserved accordingly. The locations of the Boreholes are shown on the Fig. A-2 (Appendix-A).

Soil

 

The following field work was planned for this project:

 

a.         Project “Gulberg Mall and Residency” will built on two plots, i.e. Plot No. 1 and Plot No. 2.

 

b.         Six (06) Boreholes were planned at the level of 100 ft in Plot No. 01 using Straight Rotary Machine below the existing surface level at designated locations specified in Fig A-2 of Appendix-A.

c.         Five (05) Boreholes were planned at the level of 100 ft in Plot No. 02 using Straight Rotary Machine below the existing surface level at designated locations specified in Fig A-2 of Appendix-A.

d.         To collect the disturbed soil samples from the boreholes.

 

e.         Preservation of Sand Stone/Shale Core Samples and Soil Samples in Core Boxes as per ASTM Standard.

 

2.2       DRILLING OF BOREHOLES

 

Accordingly, six (06) Boreholes were drilled at the level of 100 ft in Plot 01 and five (05) Boreholes were drilled at the level of 100 ft in Plot 02 below from Existing Ground Level (EGL) through Straight Rotary Machine with Bentonite as the drilling fluid. The diameter of Boreholes was kept as 4.0 inch.

 

Field Borehole logs were developed on the basis of the materials encountered at the site and was later confirmed on the basis of the laboratory test results. The Borehole logs of Eleven (11) Boreholes are appended to this report as Appendix-B.

 

2.3       CORE RECOVERY

 

The Rock Core Recovery from the different borehole is in average of 17.3 %.

 

  

2.4       ROCK QUALITY DESIGNATION (RQD)

 

The Rock Quality Designation (RQD) remains very poor and recorded in the range of 5.5 %.

 

 

2.5       STANDARD PENETRATION TESTS (SPTs or CPTs)

 

Standard/Cone Penetration Tests (SPTs) were performed in the Bore holes according to latest ASTM D-1586, generally at 5 ft depth interval below the existing level. The data obtained from these tests was utilized to assess the in-situ denseness of the subsurface materials. The SPT blow counts were recorded for 18-inch total penetration of split barrel sampler. The number of blows need and required to drive the sampler for through the at last 12 inches viz. ‘N’ you can values have been shown on the following respective Borehole on log sheets. The variation of field as well as corrected (for energy and overburden) SPT values (N’70) duly plotted against depth is shown in . C-1 and C-2 (Appendix- C).

 

2.6       DISTURBED SAMPLING

 

The SPT samples obtained from overburden soils in the Bore holes were properly labeled and preserved in polythene bags and plastic jars as disturbed samples.

 

For determination of the in-situ moisture content, small soil samples were also collected in tin cans from the depths where density tests were carried out. These were weighed at the site and subsequently sealed and labeled for dispatch to the laboratory for evaluation of moisture by oven drying method.

 

All the disturbed samples were transported to the testing laboratory.

 

2.7       WATER SAMPLES

 

Groundwater was not encountered at site during the site investigation in March 2019.