The Influence of Pipe Flow on Slope Stability.

Abstract

Well connected macropores running almost parallel to surface, are commonly found in forest soil. It is called "soil pipe" and water flow which go through them are called "pipe flow". This paper reviews the studies on the influence of water flow in soil pipe on slope stability with regard to rainfall intensity, and present a guideline for more practical discussion. In the case of normal rainfall event, soil pipes contribute to quick discharge of rain water which result in slope stability. Soil pipes, however, are a dead-ended pathway, which do not always work for rapid runoff system and induce slope failure. On the other hand, in the case of large rainfall event, soil pipes may not contribute to slope stability through excess infiltration beyond the drainage ability of lateral pipes and they are collapsed by underground erosion. These phenomena bring about high pore water pressure and slope failure. In order to understand and evaluate the influence of pipe flow on slope stability, three aspects should be studied: 1) are these phenomena universal? 2) quantative evaluation of influence on rain-runoff process, 3) how do they change their structure? Key ward: Pipe flow, Slope stability, Slope failure, Runoff system •@ŽR • ŽÎ-Ê"y'w"à ‚É‚Í 'n •\-Ê‚AE‚Ù‚Ú•½•s ‚Ƀp ƒCƒv ‚AE OEÄ ‚Î ‚ê ‚é˜A'± ‚µ ‚½‹ó "´ ‚ª ' ¶ •Ý‚· ‚é ‚± ‚AE ‚ª •L ‚-Šm "F ‚³ ‚ê ‚Ä‚¢ ‚é.‚± ‚¤ ‚µ ‚½ƒpƒCƒv ‚É ‚ae‚é •… ˆÚ"®‚ª ŽÎ-ʈÀ'è ‚É-^ ‚¦ ‚é‰e ‹¿ ‚ɂ‚¢ ‚Ä,OE¤‹ † ‚Ì OE» •ó ‚ðOEŸ "¢ ‚µ,‰ð-¾‚· ‚× ‚«-â'è ‚ð'ñ Ž¦ ‚· ‚é.-{ •e ‚Å‚Í ƒp ƒCƒv-¬ ‚Ì ŽÎ-ʈÀ'è ‚É-^ ‚¦ ‚é ‰e ‹¿ ‚ð'Ê•í ‚Ì •~ ‰J Žž‚Ì OE» •Û ‚AE 'å ‚« ‚È•~ ‰J Žž‚Ì OE» •Û‚É•ª-Þ ‚µ ‚½.'Ê •í ‚Ì •~ ‰J Žž‚É‚Í ƒp ƒCƒv‚Í-Ç •D‚È"r •…ƒVƒXƒeƒ€ ‚AE‚µ‚Ä"-‚«,ŽÎ-ʈÀ'è ‚ÉŠñ-^ ‚· ‚é ‚AE •l ‚¦ ‚ç‚ê ‚é.‚µ ‚©‚µ,ƒp ƒCƒv‚Í ‰º-¬ '[ ‚ª •Â•Ç ‚µ‚Ä‚¢ ‚é ‚± ‚AE‚à•l ‚¦ ‚ç‚ê,‚± ‚Ì ‚ae‚¤ ‚ȃp ƒCƒv‚Í "r•…ƒV ƒXƒeƒ€ ‚AE‚µ‚Ä ‚Í •s Š® 'S ‚Å‚ ‚邽‚ß,•ö ‰ó ‚Ì-v ˆö ‚AE‚È‚é ‚± ‚AE ‚ª •l ‚¦ ‚ç‚ê ‚Ä‚¢ ‚é.ˆê •û,'å ‚« ‚È•~ ‰J Žž‚É‚¨‚¢Žž‚É‚¨‚¢ ‚Ä‚Í,•Z " §•…-Ê ‚Ì "r •… ƒVƒXƒeƒ€‚Ì ‹-e-Ê ‚Ì '´ ‰ß ‚¨‚ae‚Ñ‚¨‚ae‚Ñ'n ‰º •N•H‚É ‚ae‚é"r •…ƒVƒXƒeƒ€‚Ì "j ‰ó ‚ª •… ‚Ì •W' † ‚ðˆø ‚«‹N ‚± ‚µ,ƒp ƒCƒv‚ª •ö ‰ó ‚Ì-v ˆö ‚AE ‚È‚é ‚± ‚AE ‚ª •l ‚¦ ‚ç‚ê ‚Ä‚¢ ‚é.ƒp ƒC ƒv‚ª ŽÎ-ʈÀ'è ‚É-^ ‚¦ ‚é ‰e ‹¿ ‚ð‰ð-¾‚· ‚é ‚½‚ß ‚ÉOEŸ "¢‚· ‚× ‚«Ž-•€ ‚AE‚µ ‚Ä,1)ŠÏ Ž@ ‚³ ‚ê ‚éOE» •Û‚ª ‹ó ŠÔ"I •E ŽžŠÔ"I ‚É•• •Õ"I ‚©"Û‚©‚ðOEŸ "¢‚· ‚é,2)ƒp ƒCƒv‚Ì •~ ‰J-¬ •o ‰ß 'ö ‚É‹y ‚Ú‚· ‰e ‹¿ ‚ð 'è-Ê "I ‚É•] ‰¿ ‚· ‚é,3)ƒp ƒCƒv‚Ì •\ '¢ ‚Ì "®"I •Ï ‰» ‚ð•] ‰¿ ‚· ‚é,‚Ì3"_ ‚ª •l ‚¦ ‚ç‚ê ‚é. ƒL•[ ƒ• •[ ƒh:ƒp ƒCƒv-¬,ŽÎ-ʈÀ'è,•ö ‰ó,"r •…ƒV ƒXƒeƒ€ ‚h.‚Í ‚ ¶ ‚ß ‚É •@ŽR• ŽÎ-Ê "y 'w "à ‚É ‚Í ‰" '¼ ‹y ‚Ñ'n •\-Ê ‚AE‚Ù‚Ú•½•s ‚É ƒp ƒCƒv ‚AE OEÄ‚Î ‚ê ‚é˜A‚é˜A'± ‚µ ‚½‹ó "´ ‚ª ' ¶ •Ý ‚· ‚é ‚± ‚AE‚ª •L ‚-Šm"F ‚³ ‚ê ‚Ä ‚¢ ‚é.‚± ‚Ì ƒp ƒCƒv ‚Í •¬ "®•¨ ‚Ì Šˆ"Šˆ"®,•A •¨ •ª ‚Ì •…‹€,'n ‰º•…‚É ‚ae ‚é •N•H ‚È ‚Ç-l•X ‚È-v ˆö ‚É ‚ae ‚è OE`•¬ ‚³ ‚ê ‚é ‚AE•l ‚¦ ‚ç ‚ê ‚Ä ‚¢ ‚é(Beven and Ger-mann,1982‚È ‚Ç).‚± ‚ê ‚ç ƒp ƒC ƒv ‚ª ŠÖ-^‚· ‚é •…ˆÚ "®‚Í ŽR• ŽÎ-Ê "à ‚Ì •~ ‰J-¬•o ‰ß 'ö ‚Í ‚à ‚AE‚ae ‚è,•ö ‰ó•E'n OE` "-'B ‚É ŠÖ-^ ‚µ ‚¤ ‚é-vˆö ‚Å ‚ ‚é ‚AE•l ‚¦ ‚ç ‚ê ‚Ä ‚¢ ‚é(-k OE´,1995‚È ‚Ç).-{ •e ‚Å ‚Í,‚± ‚Ì ‚¤ ‚¿ ŽÎ-Ê ‚É•½ •s ‚É "-'B ‚· ‚é ƒp ƒCƒv ‚É '•-Ú‚µ,‚± ‚¤ ‚µ ‚½ ƒp ƒCƒv ‚É ‚ae ‚é •…ˆÚ"® *‹ž "s 'å Šw'å Šw‰@ •@• §606•@‹ž "s •{ ‹ž "s Žs• ¶ ‹ž ‹ae-k "'•ì 'Ç•ª '¬