one engineer started to cross section a lake to be dredged, but never completed the work. another engineer cross sectioned the lake post construction-excavation. The only measurment of the amounts removed are the truck load counts. Any ideas on how to determine the volume of material removed by truck load if cross section data is not available?
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non existing cross sections method of measurment
- Thread starter dredgman
- Start date
dicksewerrat
Civil/Environmental
Get the average volume of each load. Divide the total volume found that way be a factor of 1.15, fluff factor. this might give you aballpark number. the fluff factor is the increase in volume due to the excavation and dumping in the trucks. Look for pictures of the project.
Another way would be to use the weight of the material and do a compaction test on it. Bring it back to the same density as material very close to the 'lake'. I
f you have none of this data, use the volume of the water in the lake now as the removed quantity.
Another way would be to use the weight of the material and do a compaction test on it. Bring it back to the same density as material very close to the 'lake'. I
f you have none of this data, use the volume of the water in the lake now as the removed quantity.
KRSServices
Civil/Environmental
If the material is wet, as most dredging spills are, then there will not be any fluff. You have to determine the amount of water in the material and calculate the material quantity based on the "average" load.
KRS Services
KRS Services
The following formulae solve the above problem
v1 = Dry density (loaded in truck )
--- ----------------------------------
v2 Dry density ( in dreded area )
v1 = volume of material excavated
v2 = volume of material loaded
The following data required
Dry density : This can be calulated by knowing the water content W (field )
Dry density = Bulk density / (1 + w )
Bulk density of loaded soil : weight/volume (loaded one truck soil)
water content : it will get by OVEN DRYING method
SECOND METHOD:
V1/V2 = (1+ e1)/(1+ e2 )
e1= void ratio(in field)
e2= void ratio(loaded truck )
v1, v2 are same as above given notations
void ratio can be calculated by e * Sr = W * G
where e = void ratio , Sr = degree of saturation, w = watercontent, G = specific gravity of soil
____________________________________________________________ A. RAVI SHANKAR B.Tech, INDIA , HYDERABAD
___________________________________________________________
v1 = Dry density (loaded in truck )
--- ----------------------------------
v2 Dry density ( in dreded area )
v1 = volume of material excavated
v2 = volume of material loaded
The following data required
Dry density : This can be calulated by knowing the water content W (field )
Dry density = Bulk density / (1 + w )
Bulk density of loaded soil : weight/volume (loaded one truck soil)
water content : it will get by OVEN DRYING method
SECOND METHOD:
V1/V2 = (1+ e1)/(1+ e2 )
e1= void ratio(in field)
e2= void ratio(loaded truck )
v1, v2 are same as above given notations
void ratio can be calculated by e * Sr = W * G
where e = void ratio , Sr = degree of saturation, w = watercontent, G = specific gravity of soil
____________________________________________________________ A. RAVI SHANKAR B.Tech, INDIA , HYDERABAD
___________________________________________________________
As I understand it you have no initial ground sections but only cross-sections after excavation. Presumably,the contractor is claiming payment based on the quantity removed determined on the basis of the capacity of the trucks.
Do you have any way to determine the original ground levels. How about taking some shots just outside of the excavated area. Does your post construction shots extend beyond the excavated area ( I presume that it does in nornal survey work of this kind). If so can you use the elevation of the unexcavated areas to establish original ground with some assumptions. This can be checked against the survey outside of lake area as suggested previously. I would use this info to determine the vol excavated.
This quantity would not likely agree with the load count volumes. In terms of truck loads with dredge spoil. It depends on the nature of the spoil material. If it is clay and comes up in excavated lumps after removal of an initial thickness then I would venture to say that the trucks would not be more than 80 % filled. I would use a factor of 1.10 appplied to the truck volumes in the same manner as dicksewerrat has indicated based on the assumption that inplace volume is being paid for.
Generally if no measurements were taken by survey and this was the basis for payment then one may have to strike a compromise with the contractor or one does not have much to hang on in a court of law. These are often long and drawn out issues that put the money in the hands of lawyers only.
Compromize is often the best route
Do you have any way to determine the original ground levels. How about taking some shots just outside of the excavated area. Does your post construction shots extend beyond the excavated area ( I presume that it does in nornal survey work of this kind). If so can you use the elevation of the unexcavated areas to establish original ground with some assumptions. This can be checked against the survey outside of lake area as suggested previously. I would use this info to determine the vol excavated.
This quantity would not likely agree with the load count volumes. In terms of truck loads with dredge spoil. It depends on the nature of the spoil material. If it is clay and comes up in excavated lumps after removal of an initial thickness then I would venture to say that the trucks would not be more than 80 % filled. I would use a factor of 1.10 appplied to the truck volumes in the same manner as dicksewerrat has indicated based on the assumption that inplace volume is being paid for.
Generally if no measurements were taken by survey and this was the basis for payment then one may have to strike a compromise with the contractor or one does not have much to hang on in a court of law. These are often long and drawn out issues that put the money in the hands of lawyers only.
Compromize is often the best route
It's not likely you will be able to agree with the contractor on the actual volume of soil removed. Since the contractor was allowed to remove the material and simply count the truck loads, you may have to negetiate a rate per truck load and pay by the load. This should have been agreed to prior to the work being done.
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