单点冲击荷载下红砂岩土的位移规律探析

Analysis on displacement law of red sandstone soil under single- point impact loads

利用4种不同的夯击能量（25N·m、30N·m、35N·m和40N·m）对赣南地区红砂岩土进行室内击实试验。试验研究表明：在单点冲击荷载作用下，红砂岩土的累计夯沉量随击数的增加其变化过程表现为较快增长和缓慢增长两个阶段，25N·m、30N·m、35N·m和40N·m能级下累计夯沉量呈现两阶段的分界点分别为第7击、第8击、第9击和第10击，具有明显推后的现象；各方案下的累计夯沉量与击数之间基本符合公式Y=Ax／（1＋Bx）的关系；15N·m、20N·m、25N·nl、30N·m、35N·m和40N·nl能级下的累计夯沉量随着相应最佳击数的变化具有较好的线性特征；随着单击夯击能（25N·m、30N·m、35N·m、40N·m）的增加，发生显著位移的土体范围在水平方向上从4．5～5．0cm变化至6．0～6．5cm，在竖直方向上从13．5～14．0cm变化至17．0～19．0cm。

By using four different tamping energy（25 N · m,30 N · m,35 N · m and 40 N · m） which is refitted to do the laboratory compaction tests on red sandstone soil in the southern Jiangxi. Test study shows that, the change law of the accumulated settlement of the tamper pits along with the tamping numbers can be divided into the faster and slower two phases under single-point impact loading, the demarcation point of two stages that the accumulated settlement showed were seventh,eighth,ninth and tenth strike under 25 N · m,30 N ·m,35 N · m and 40 N · m level,has significantly delayed phenomenon;the relationship of the accumulated settlement and the number of tamping under the scheme is in compliance with y = Ax/（ 1 ＋ Bx） ; the changes of the accumulated settlement amount of red sandstone soil under 15 N · m,20 N · m,25 N ·m,30 N ·m,35 N · m,40 N ·m with the corresponding best hits has good linear characteristics;with the increase of single tamping energy （25 N · m ,30 N · m,35 N · m and 40 N · m） ,the notable displacement action ranges of the soil change from 4.5～5.0 cm to 6.0 ～6. 5 cm in horizontal direction and from 13.5 ～ 14. 0 cm to 17.0～ 19.0 cm in vertical direction.