Dynamic estimating the karst tunnel water inflow based on monitoring data during excavation

The tunnel water gushing has long been a difficult hydrogeological problem, especially in karst areas. It affects the entire process of tunnel construction, operation and maintenance. In view of the complex disaster-causing mechanism and difficult quantitative predictions of water inrush, several theoretical methods are adopted to realize dynamic assessment of water inrush in the progressive process of tunnel construction. According to a survey conducted in the Zoumaling tunnel near Chongqing, China, 62% of its total length, e.g., 1525 m is associated with karst（including a fault fracture zone). On the basis of collecting real-time monitoring data about water inrush in the excavated section of the Zoumaling tunnel, a fuzzy data analysis method has been used to analyze the content of seven common ions in the inflow water, which makes it possible to classify the groundwater types and to establish the hydrogeological model of the tunnel site. In order to forecast the possibility and quantity of water inrush, it is essential to accurately model the groundwater system spatially. The preliminary forecasting result about untapped section reveals a small possibility of a sudden water inflow disaster and 35,000 m3/d water inflow, which is close to the ultimately measured quantity of water. This study provides a theoretical reference for the prediction of water inrush during tunnel construction, and the main characteristic of this study is reflected in the real-time prediction of tunnel water inrush according to actual tunnel inflow of excavated sections. This approach can be applied in similar situations for the prediction of tunnel water inrush in other karst regions. Key words: karst region, tunnel water inrush; dynamic estimate; fuzzy cluster analysis. Pricakovana dinamika vdora vode v predore na podlagi meritev med njihovo gradnjo Pojav vdiranja vode v predore je že dolgo casa poznana težava, se posebej na kraskih obmocjih. Pojavlja se med celotno gradnjo predorov, njihovo uporabo in vzdrževanjem. Za proucevanje potencialnega pojava nesrec in težavnega napovedovanja kolicine vdora vode je bilo preizkusenih vec razlicnih teoreticnih metod. Te omogocajo oceno dinamike vdora vode med celotnim procesom gradnje predorov. Pri predoru Zoumaling v bližini mesta Chongqing (Kitajska) približno 62 % dolžine predora (1525 m) poteka na obmocju krasa in cez prelomna obmocja. Na podlagi v realnem casu zbranih podatkov o vdorih vode v izkopanih odsekih predora Zoumaling se je naredila analiza mehkih množic. Ta je bila uporabljena za analizo sedmih v vodi najbolj znacilnih ionov in je omogocila razvrstitev podzemne vode v razlicne skupine, s tem pa izdelavo hidrogeoloskega modela neposredne okolice predora. Za analizo verjetnosti vdora vode in njene možne kolicine je izdelava natancnega modela vodonosnika zelo pomembna. Prvi rezultati, ki se nanasajo na en se nedokoncan odsek, kažejo na majhno možnost nenadnega vdora vode. Najvecja možna dnevna kolicina vdora je ocenjena na 35.000 m3, kar je blizu najvisje izmerjene dnevne kolicine dotoka. Pricujoca raziskava vzpostavlja teoreticno podlago za napoved vdora vode v casu gradnje predora, glavna posebnost pa je napoved vdora v realnem casu na podlagi izmerjenega dotoka v že izkopanih odsekih predora. Predstavljen postopek in napovedi, ki jih omogoca, se lahko uporabijo v podobnih primerih tudi na drugih kraskih obmocjih. Kljucne besede: krasko obmocje, vdor vode v predore, pricakovana dinamika, analiza mehkih množic.