The Rock And Soil Of Xigeda Stratautilized For Highway Roadbed Filler

The highway from Xichang (Huanglianguan) to Panzhihua is an important economic arterial road run-through Sichuan from south to north. Approximate one hundred of the highway go on Xigeda strata. Xigeda strata is the stillwater sediment of astatic lake facies at early stage of Quaternary Period. Because of soft lithology, low intensity and very bad stability the strata is well-known in China. Many geologic hazard in Panxi are related to the sliding layer of Xigeda strata.When the highway from Xichang (Huanglianguan) to Panzhihua is constructed, the cutting of rock and soil in Xigeda strata is over one million. If the cutting is discarded, not only lots of farmland is occupied and project investment is increased, but also the environment will be break down. Firstly engineering character and aptness for highway roadbed filler of rock and soil of Xigeda strata are researched by analysing the experiments. Researching the aptness has not been reported. The research would fill up the blank that rock and soil of Xigeda strata is utilized for highway roadbed filler. Secondly construction process for roadbed filler is made certain by detecting in situ and controling constructing. The research result indicates:1. Xigeda strata lithology could be classed to sandstone and mudstone. Sandstone is classed to packsand and pelitic siltstone. The mudstone is mostly silt mudstone. Bedding of Xigeda strata is very evident. Water content of sandstone is low. Water content of mudstone is high to about percent 20 ~ 40 generaly, and bound water is sealed. If admixed, they are gradation in reason and in favor of compaction. So they would be well filler.2. Loose laying depth of mixed filler made of Xigeda strata rock and soil was set to 20, 25 , 30, 35 , 40 and 45cm . And by measuring their degree of compaction insitu we confirmed that fit loose laying depth to the filler. The depth is 30cm~35cm for weighing method; For method of the experiment in situ (sand cone method) the depth is 30cm~35cm for rolled by 16t roller method, 35cm~40cm for rolled by 18t roller method. The filler's optimal water content is percent 15-17. Coefficient of loose laying is an important index for road constructing. When the mixed filler made of Xigeda strata rock and soil is paved manually coefficient of loose laying is 1.42 and the more is loose laying depth the less is number value. The criterion regulates that the coefficient of loose laying is 1.22 for paving with the most current loader,and 1.26 for pavingwith the excavator.3. When compaction process is strong vibration prior to weak vibration, the mixed filler made of Xigeda strata rock and soil could meet the need of degree of compaction for rolled by 16t or 18t roller 4 or 5 time, when compaction process is weak vibration prior to strong vibration, the mixed filler could meet the need of degree of compaction for rolled 7 or 6 time. The constructing process for the mixed filler made of Xigeda strata rock and soil adapts to the method of strong vibration prior to weak vibration.4. The location that possesses Xigeda strata rock and soil has alson quartz diorite. According to the criterion and the geology along the line of the highway, the embankment and roadbed are reclaimed with the diorite and the mixed filler made of Xigeda strata rock and soil to layering. The fit times rolled by 16t roller is 5(static pressure 1 time+strong vibration 3 time+ static pressure 1 time), and by 18t roller is 6(static pressure 1 time+strong vibration 4 time+ static pressure 1 time) when granodiorite's loose laying depth is 30cm in the experiment. The compaction effect of 16t roller is better than 18t roller.