Study on a conventional method of an allowable local settlement and barrier performance of the compacted soil barrier layer in waste landfill

对在碎石砂中掺入10%钠型膨润土制成的压实土防渗层进行了室内活板门试验和现场局部沉降试验。结果表明：沉降带末端上方土层底面出现裂缝，裂缝呈倾斜向上扩展，顶面裂缝宽度大于2mm的区域屏障作用明显减弱，在土壤层下放置土工网对防止裂缝的产生和发展有点效果，并且增加液体的钙离子浓度降低出现裂缝时的局部沉降值。通过对试验数据的分析，得到裂缝延伸至土层中间高度时的角变形值为0.16。根据角度变形，估计允许的局部沉降约为50 mm。

Trap door tests in the laboratory and local settlement tests in the field for the compacted soil barrier layer that was made by mixing a sodium type bentonite of 10 % into crashed rock sand were conducted. The main results are that a crack appeared on the bottom surface of the soil layer just above the end of settling zone and progressed upward slantingly, the area having a crack wider than 2 mm on the top surface decreased considerably the function of barrier, placing a geonet beneath the soil layer was a bit effective to prevent a crack from creating and progressing and increasing a concentration of calcium ion of the liquid decreased a value of local settlement at which a crack appeared. Then the value of angle deformation at which a crack extended to the middle height of the soil layer was found to be 0.16 by analyzing the experimental data. The allowable local settlement was estimated to be around 50 mm based on the angle deformation.