| Abstrakt: |
The accuracy of obtaining strength parameters of soil is considered a major role for any soil engineer seeking for accurate design. The overestimation or underestimation of such parameters will no doubt leads to a dangerous or exaggerated foundation design or any design related to soil parameters. In both cases no firm soil agency will approve such sequences. The accuracy of soil tests, and in precise, the laboratory testing is by far important the most for soil design. In this research an attempt is followed to make an accuracy study on a randomly chosen three Iraqi soil laboratories. As such, two soil samples were chosen from two different locations in Baquba discrete. One soil is a CL clay and the other is a SW-SC sand. Each specimen of soil is tested by authors carefully five times, unconfined compression test for the clay and direct shear box test for the sand, as to get cohesion for soil 1 and friction angle for soil 2. Highly due care is experienced as these trial tests is for the accuracy comparison. Then after, each soil sample is carefully mixed and subdivided into six soil specimens, each pair is sent to a different soil laboratory for testing. The results obtained from those laboratories revealed that two laboratories have deviated in results in about 5 and 8% as a relative error in testing cohesion, the other laboratory, designated as Lab.B, has a relative error of 13%. In terms of friction angle, the same two laboratories have deviated in almost the same relative errors as for the cohesion. Unfortunately, the Lab.B, has deviated by 45% in relative error or 16o more in measuring the friction angle. The last fact reflects a serious problem especially in designs that are mostly sensitive to friction angle such as the bearing capacity of soil. [ABSTRACT FROM AUTHOR] |
