conducting soil investigation works for various bridges and culverts in kottayam district , investigation works , 56 . 1 . a : mobilization including transportation of all necessary plan and equipments and materials of boring field testing and sampling and demobilization after completing the workfor machine boring , 56 . 2 . a : setting up boring at each bore hole locations including carrying all necessary plant , equipment and materials of boring and field tests and collection of samples at each bore hole location . for machine boring . , 56 . 3 . a . 1 : boring with rotary power drilling equipments inall types of soil having n value less than 50 excluding hard rock soft rock , or medium rock for strata upto 10m . including conducting necessary s . p . t and recovery of un disturbed soil samples at 5m . intervals . for ordinary soil . , 56 . 3 . b . 1 : boring with rotary power drilling equipment inall types of soil having n value less than 50 excluding hard rock soft rock , or medium rock for strata for next 10m upto a depth of 20m including conducting necessary s . p . t and recovery of un disturbed soil samples at 5m . intervals . for ordinary soil , 56 . 5 . a : boring through all classes of rock excluding hard rocks having n value greater than 50 using tungsten carbide drilling bit . in land . , 56 . 4 : boring through all type of hard rock or similar refusal strata of n value greater than 50 using diamond core drilling bit for in land under and banks of river . , 56 . 7 : conducting standard penetration test in bore hole at any depth . , 56 . 11 . a : compilation of all field data with recommendation for a suitable foundation after conducting necessary lab test ( report in triplicate ) machine boring for 5 bore holes .