重庆地区红层泥岩侧限膨胀性能试验研究

Experimental Study on Confined Swelling Characteristic of Redbed Mudstone in Chongqing

以重庆地区侏罗系中统沙溪庙组红层泥岩为研究对象,通过侧限无荷膨胀和有荷膨胀室内试验,研究了侧限无荷、有荷及不同加水条件下的膨胀性能。结果表明,红层泥岩侧限无荷膨胀呈现3个膨胀变形阶段,第1阶段膨胀变形较快,膨胀量较大,第2阶段膨胀具有增速特征,95%的膨胀量在前2个阶段完成;竖向荷载对红层泥岩侧限膨胀变形的抑制作用明显,随着竖向荷载的增大,侧限有荷膨胀率急剧降低;侧限无荷条件下,短时间内,初期的水量大小对泥岩膨胀性能影响不明显,但随着时间持续,水量大小对稳定膨胀量、膨胀变形过程及其特征起着控制作用。

In this paper,by means of confined free swelling test and confined swelling test under loads,redbed mudstone of Shaximiao group in the Middle Jurassic in Chongqing area is present to study its swelling characteristics under confined free and loading conditions,and swelling under different water injections as well.Results reveal that three phases are present in the confined free swelling of mudstone,fast swelling deformation and high swelling increasment in the first phase and increasing swelling velocity in the second phase.95 percent swelling occurs in the former two phases.It is found that vertical loads greatly restrain the confined swelling of mudstone.The confined loading swelling ratios decrease sharply with the increasing vertical loads.Moreover,the amount of water has no obvious effect on swelling characteristic of red bed mudstone within a short time under confined without load,but it plays a controlling role on the stable swelling capacities,swelling processes and characteristics as time lapsing.