基于季节性河流大沽河河床砂样的侧向非饱和入渗试验研究

Experimental study on lateral infiltration based on the seasonal Dagu riverbed sands

选取青岛段大沽河上、中、下游三处具有代表性河床砂样作为试验用砂,进行侧向非饱和入渗试验.结果表明,非饱和入渗率随时间变化趋势可分为三个时期,分别为入渗率快速下降期、入渗率缓速下降期和稳速入渗期.细砂初始含水率为1.85%和5.79%时,稳定入渗率分别约为2.5×10^(-4)和2.3×10^(-4) m/s;中砂初始含水率为1.39%和4.32%时,稳定入渗率分别约为2.7×10^(-4)和2.6×10^(-4) m/s;粗砂初始含水率为1.98%和2.44%时,稳定入渗率分别约为2.8×10^(-4)和2.6×10^(-4) m/s.同种砂样初始含水率越小则侧向入渗速率越快.初始含水率相同或相近的情况下,细沙、中砂和粗砂的稳定入渗率依次增大.

Typical riverbed sand samples collected from the upstream, midstream and down-stream of the Qingdao section of the Dagu River are used to carry out the unsaturated lateral infiltration experiments. The results indicate that the trend of unsaturated lateral infiltration rate with time can be classified into three phases, i. e. rapid decreasing, slowly decreasing and steady infiltration rate. The lateral-stable infiltration rate was about 2. 5 × 10-4 and 2. 3× 10-4 m/s of fine sand when the initial moisture content is 1. 8 5 % and 5. 79%. The lat-eral-stable infiltration rate is about 2. 7X10-4 and 2. 6X 10-4 m/s of medium sand when the initial moisture content is 1. 3 9 % and 4. 32%. The lateral-stable infiltration rate is about 2. 8X 10_4and 2. 7X 10-4 m/s of coarse sand when the initial moisture content of fine sand is L 98% and 2. 44%. In the case of the same sand, the smaller the initial water content be-comes, the faster the lateral infiltration rate is. In the same or similar initial moisture con-tent case, the stable infiltration rate of fine sand, medium sand and coarse sand increases in turn.