岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
2期
423-428
,共6页
泥水盾构%泥膜%形成时间%影响因素
泥水盾構%泥膜%形成時間%影響因素
니수순구%니막%형성시간%영향인소
slurry shield%filter cake%forming time%influencing factors
泥水盾构施工中,维持开挖面稳定的关键是要在开挖面及时形成微渗透的泥膜,才能将泥浆压力转化为有效应力来平衡开挖面的土压力。开挖面处的泥膜是动态泥膜,所以泥膜的形成时间是影响泥膜能否有效支护开挖面稳定的重要因素。利用自行设计的泥膜形成时间测量试验装置,在3种地层中,利用5种泥浆开展泥浆渗透成膜试验,研究泥膜的形成时间及相关规律。研究表明,在泥皮型渗透中泥膜的形成时间一般为10 s左右,泥浆性质及粒径对泥膜的形成时间有重要影响。讨论了国内外部分大型泥水盾构泥膜形成时间,发现泥膜从破坏到形成、再到破坏的时间间隔为5~20 s不等,因此,在实际施工中需要调整泥浆性质,使泥膜形成时间小于泥膜从破坏到再破坏的时间。
泥水盾構施工中,維持開挖麵穩定的關鍵是要在開挖麵及時形成微滲透的泥膜,纔能將泥漿壓力轉化為有效應力來平衡開挖麵的土壓力。開挖麵處的泥膜是動態泥膜,所以泥膜的形成時間是影響泥膜能否有效支護開挖麵穩定的重要因素。利用自行設計的泥膜形成時間測量試驗裝置,在3種地層中,利用5種泥漿開展泥漿滲透成膜試驗,研究泥膜的形成時間及相關規律。研究錶明,在泥皮型滲透中泥膜的形成時間一般為10 s左右,泥漿性質及粒徑對泥膜的形成時間有重要影響。討論瞭國內外部分大型泥水盾構泥膜形成時間,髮現泥膜從破壞到形成、再到破壞的時間間隔為5~20 s不等,因此,在實際施工中需要調整泥漿性質,使泥膜形成時間小于泥膜從破壞到再破壞的時間。
니수순구시공중,유지개알면은정적관건시요재개알면급시형성미삼투적니막,재능장니장압력전화위유효응력래평형개알면적토압력。개알면처적니막시동태니막,소이니막적형성시간시영향니막능부유효지호개알면은정적중요인소。이용자행설계적니막형성시간측량시험장치,재3충지층중,이용5충니장개전니장삼투성막시험,연구니막적형성시간급상관규률。연구표명,재니피형삼투중니막적형성시간일반위10 s좌우,니장성질급립경대니막적형성시간유중요영향。토론료국내외부분대형니수순구니막형성시간,발현니막종파배도형성、재도파배적시간간격위5~20 s불등,인차,재실제시공중수요조정니장성질,사니막형성시간소우니막종파배도재파배적시간。
In slurry shield construction, forming a filter cake in time is important for working face stability;the slurry pressure could be transferred into effective stress with filter cake then acting on the working face. The filter cake on the working face is dynamic, thus the forming time of filter cake is the main factor which could affect the supporting for working face. An apparatus is designed which could measure the excess pore pressure in the stratum. Infiltration tests are done in three kinds of high permeability strata with five kinds of slurry to study the forming time of filter cake, its supporting ability and the influencing factors. The results indicate that the forming time of filter cake is 10 seconds in only filter cake infiltration styles. The slurry property and the grain size of stratum have important effects on the forming time of filter cake. The filter cake forming time in part of large slurry shields at home and abroad is also discussed; and the results indicate that the time from destruction to re-destruction of filter cake is ranged from 5 seconds to 20 seconds;thus the property of slurry should be suitable to ensure that the forming time of filter is less than the time from destruction to re-destruction of filter cake.