Construction & Contractors/foundation column on river rock bouldeR
I AM FROM HYDERABAD INDIA I PURCHASE LAND NEAR MUSI RIVER IN HYDERABAD THAT LAND FILLED WITH ROCK BOULDER UP 15 FEET COMPLETE AREA IT IS SMALL AND LARGE BOULDERS MY QUESTION IS HOW TO CONSTRUCT FOOTING COLUMN ON THAT PART OF AREA PLEASE ANSWER ME IN DETAIL ATTACH PICTURE ON FILE
In my opinion that material is uncontrolled rock fill probably disposed from another construction site elsewhere. Between the boulders is loose dirt. Under load from shallow footings the dirt will rearrange and the boulders will shift. As such the material should not be built upon until it is removed and recompacted, otherwise large differential settlements are likely. If it is a small site and you have sufficient funding you may be able to grout the fill, in other words, permeate the spaces between the loose boulders with cement grout that will support the boulders so they cannot shift, and then place spread footings, but this will entail drilling holes all through the loose fill to solid, native material and injecting the grout through those holes, under pressure. Drilling holes that will stay open is difficult in this kind of material. Another option would be to drill holes and place reinforced concrete piles but for that, in this kind of ground, you will need a casing advancement method such as ODEX. There are specialty foundation contractors who will do this kind of work but it is expensive. It is probably not as expensive as the grouting option.
I am sorry to tell you this but if you expect the structure to be safe and to perform, you are going to have to correct this loose ground condition.