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:Hi.

Footing of one column in my construction is next to sump tank the size.of the footing is 5'9" x 8'. Next to this column in basement I am constructing water sump.
The depth of footing is 8 feet and there will be partial basement of 3 feet depth and there will be a sump tank in this basement.

JCB guy while digging pit cut the soil more so the soil below footing was also cut by 1'6".
Contractor has filled this space by constructing a solid block wall so now footing will partially come over this solid block filling instead on un-excavated soil . Area of.portion is 1'6" x 5'9" the depth filled by blocks is around 8 feet.

Is it a problem.that around 18% of.footing area rests over filling of solid.blocks instead of un-excavated earth ?
After the solid.blick wall fill there will be RCC wall of tank and om the top in continuation RCC retaining wall will run

See the picture attached for clarity
If there is a problem what could be the remedy ?

I have asked structural engineer to.visit before concrete pouring is done however seeking valued opinion of forum.members.

The footing is going to be around 1 feet thick and there will be pedestal around column. Reinforcement for pedistal is not done yet so not seen in picture.

I don't think the concrete wall is capable of withstanding the load of the building. A better option would be to dig all the way to the bottom of the sump and start the column from there. I am not a structural engineer, go with your structural engineer's advice.

Blocks usually aren't designed for footing load bearing.. dig all the way down, or fill it with solid concrete, reinforced by TMT

Well yes that was the dilemma however
When I do the calculations the SBC of the site was 8 Tonne per sq meter or or 0.078 newton per sq mm.

Compressive strength of solid blocks is taken as 3.5 newton per sq mm which is 50 times of soil

So theoretically solid blocks have more comprehensive strength then SBC of sandy clay soil. Am I doing something wrong in this comparison ?

Footing size is kept big and 18% of area is on block fill

Starting foundation from still lower level would mean making the footing 12 feet deep instead of current 8 feet so extra 4 feet column and extra 4 × 6 feet of retaining wall for basement as well.

Block wall is removed instead this 1.5 feet width will be filled with concrete before casting the footing.
Footing depth is kept same just for extra digging the area will be backed with concrete

Thanks everyone