UNDERGROUND FLOW THROUGH PIPES AND ITS INFLUENCE TO LANDSLIDES

对地下管道排放的两年观察清楚了以下几点。首先，在一个小洞里发现了十根天然管子。七根管道中的三根管道位于空心的下游端，始终排放水。其他的只在大雨时排水。直接排放的大部分体积被管道水流覆盖。其次，只有在前期降雨和降雨强度足够的情况下，才能看到管道水流。第三，管道流量的模式与降雨模式相对应。第四，管道排放率有上限。极限可以由管道的尺寸来控制。第五，挖出了两根管子。它们只有50厘米长，形成一层砾石。这意味着，在这种情况下，从这些管道流出的流不应该被称为管道流，而应该被称为砾石层流。第六，用储罐模型解释管道的流出率。这些事实可能解释降雨高峰时间与泥石流和（或）滑坡发生时间之间的巧合，而这些都不能用假设均质土层的理论来解释。然而，通过管道的平滑流出并不能解释泥石流的发生。在观测期内发生了一次管道垮塌，这种垮塌增加了水力压力，可能引发滑坡。

A two-year observation of the discharge from underground pipes made the following things cclear.First, ten natural pipes were found in a small hollow. Three pipes of the seven pipes, which are located at the downstream end of the hollow, always discharge water. The others drain only during heavy rains. Most of the volume of the direct discharge is covered by the pipe water flow.Second, the pipe water flow can only be seen when the antecedent rain and rainfall intensity is enough.Third, the patterns of the pipe flow rate correstpond well to rainfall patterns.Forth, the discharge rates from the pipes have the upper limits. The limits may be controlled by the dimensions of the pipes.Fifth, two pipes were dug out. They last only 50 cm long and lead to a layr if gravel. This means that the flow that comes out of these pipes should in this case not be called pipe flow but rather gravel layr flow.Sixth, the outflow rates from pipes are will explained with a tank model.These facts could possibly explain the coincidence between the peak time of rainfalls and the time of the occurrence of debris flows and/or landslides that have not been able to be explained by theories developed assuming homogeneous soil layrs. Smooth outflow through pipes, however, does not explain the occrrence of debris flow. Pipe collapse can happened and yhis was observed once during the observation period, these collapses increase the hydraulic pressure and may trigger landslides.