以動態圓錐貫入儀觀察乾土料承載力之研究

• Main Author: 鄭郁志
• Other Authors: 楊朝平
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/98208183789264566709

碩士 === 中華大學 === 土木工程學系碩士班 === 91 === In light of survey subgrade condition on highway’s repairs and maintenance, it parameter of subgrade strength character is necessary for surface course’s thickness design, traditionally, there have lots kind of testing method in order to seek for some relevant parameters of subgrade, but those testing methods still exist in its pragmatically consideration, so that, it isn’t utilized commonly at present, those that being conducted into a more economically, easily, time saving and reliably investigation methods are necessary. Utilize a dynamic cone penetrometer for monitor dry soil’s bearing force. We have custom-made a huge compacting steel mold for this study, and then modulated a bind of stone crashed sand as well as four subgrade samples also, after being dried of each sample and then divided 5 various density samples, totally, 25 samples were finished for DCP penetration test at laboratory and conducted DCP’s penetration test and density test at spot, meanwhile, of that impact acceleration Ia was being tested. We found that there were different on sample’s DCP penetration curves that conduced by its kind of soils, maximum granular diameter, coarse aggregate content, it showed up its penetration curve character’s parameters were average penetration ratio APR, the more hardened soil, the less APR, the APR effectiveness of sample density, the less on stone crashed sand and A-6, but the more its gradation on A-3 soil and A-2-4 soil. The result of this study could conduce on DCP’s penetration curve character at spot and its APR data, which it distinguished from both subgrade and base thickness of soil as well as its density, we also reviewed the relation both APR, γd and Ia, basically, because of penetration difficulty the moreγd and Ia, the less APR. In equation(2.4) if APR less than 3, its CBR may unlimited, therefore, we accepted another research force task’s recommendation, valuated its CBR with coarse aggregate’s equation(4.5) was more reasonable, we also calculated that data Ia’s gradation was 81.5%, A-3 soil was 76.5%, A-2-4 soil was 69.8%, A-6 soil was 36.1%, respectively. Based on value of CBR its resilient modulus on gradation was 29.3MN/m2, A-3 soil was 282.2MN/m2, A-2-4 soil was 266.0MN/m2, A-6 soil was 174.5MN/m2.If that sample’s maximum granular diameter was less than bottom of cone diameter, then its slope of penetration curve was a constant, on contrary, it conduced easily the effect of granular cone head resistance. Due to DCP was a portable, detachable, operable device and low price advantageously, in light of this study’s the result of test had showed up that the CBR and its resilient modulus could gain at short time.