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Summary of Case 8.1: Effects of Structure on Dam Construction.




Construction of dam has farranging effects on the rocks and environment in general. Across theglobe this is a major problem occurring when the dams are put upwithout proper mapping of the place. An excessive amount of waterwithin a slope increases its mass, increasing shear stress withinparts of the slope, especially along rock fractures tilted in thesame direction as the slope surface, as is the case with the dam infocus.&nbspChangesin geological conditions which decreased competence of the rockssurrounding leads to change in composition of rocks (Jackson,l.1969). The type of rock in this area where the dam has beenconstructed is sedimentary rock and the effect of stress andweakening by the action of water can lead to problems such asinternal erosion especially this area has element of clay minerals..Building of this particular dam leaves serious effects on the rocklayer.


The primary focus of thisstudy is to establish the problem answers to the construction of theArbuckle damon the rock creek, considering the type of rock inthis area is sedimentary and characterizes of clay minerals. Arbuckledam is built on rock creek,across the floodplain, alluvium material overlie foundation rockalong the axis.&nbsp Paleozoic sediments ranging from Ordovician toPennsylvanian make up the foundation rock.&nbsp&nbspThedam construction was done by the U.S. Bureau of Reclamation wasbuilt with the intention of providing water to the locals as well asserve as recreational facility. The construction was massive but theunderlying problem on the rock, since the dam is built on the rockclearly shows that no much mapping work was carried out prior toconstruction of the dam, the foundation of the dam consists ofsedimentary bedrock beneath about twenty feet of various residual.There is likely hood the dam could begin to leak, thus resulting ininternal erosion. The main concern is how to prevent the leakage ofthe reservoir through the foundation rocks beneath the base of thedam.


Analyzing available fielddata, the effect of the dam on the rock composition, to prevent themain problem which is leakage from spreading further, is to putcement into holes drilled in a line along the valley floor, whichwill result in low permeable seal for the water to the rocks, processknown as grouting- introduction of motor to the ground to improvestiffness, strength and make it permeable.


The answer to the problemwould be cleaning the debris from the spillway conducting, repairingand resurfacing the river outlet to ensure there is no blockage ofwater and put a grout curtain to form a low-permeable seal. Thehundred and thirty five grout hole used at a space of twenty five tohundred and ten ft will reduce piping.

According to SEED report onArbuckle Dam, ‘’A Review of Operation and Maintenance reportrevealed that Arbuckle Dam was in satisfactory condition, andrecommended simple procedures such as cleaning the debris from thespillway’’.


If the grout curtain is puton holes drilled along the valley floor, will be useful to protectthe foundation of the dam from seepage or piping, it will make therock layer stiff and strong, this will ensure the rock is not eroded.


  1. United States Department of the Interior, Bureau of Reclamation, Division of Dam Safety, SEED

Report on Arbuckle Dam, GreatPlains Region: July 1985.