长江青砂压实和承载强度特性研究

Characterization of the Compaction and Bearing Strength of the Yangtze Sand

针对填砂路基施工过程中施工机械容易发生陷轮的现象,选取湖北潜江至江陵高速公路江陵段中的填砂路基进行了室内加州承载比试验,探讨了青砂的压实度和CBR值在含水率,以及击实功变化下的变化情况.研究结果表明,在击实功较小时,青砂CBR峰值含水率要略小于其最佳含水率,对于不同击实功,青砂CBR峰值都对应于最大干密度处;试验室及现场结果都说明在当地夏季阴天气候条件下,对洒水半天后的青砂进行碾压,不会产生机械陷轮的现象;在施工过程中需要不断洒水,维持青砂的含水率在最佳含水率附近,从而保证青砂碾压后的压实度.

Indoor California Bearing Ratio（CBR）tests are performed on Yangtze sand,which is sampled from the raw materials used for the sand-filling subgrade construction in the Jiangling section of the Qianjiang-Jiangling Highway,Hubei Province,to investigate why the wheels of the construction trucks are prone to sink during the sand-filling subgrade construction period.CBRtests serve the purpose of investigating how the degree of compaction and the CBRvalue of Yangtze sand changed with the water content and compaction work.The test results indicate that 1）the water content at the maximumCBRvalue is slightly lower than the optimum water content when the compact work is relatively small;2）the CBRvalue reaches to the maximum value at the maximum dry density regardless of the compact work.It can be concluded from laboratory and field tests that 1）the sink of construction truck wheels could be avoided if it is half a day after the water pouring to the subgrade when the rolling compaction on the sand-filling subgrade is conducted in the local overcast climate;2）water should be constantly poured on the subgrade during the sand-filling subgrade construction period so as to maintain the water content of Yangtze sand around the optimum water content and to ensure the degree of compaction.