Analysis The Unconfined Water Characteristics Near The Xi’an Ground Fissure

Ground fissure, as a typical geological disaster in xi ’an region, has done a lot of damageto the urban construction such as the subway and the urban lifeline engineering, brought greatinconvenience to the people. The subway engineering can’t avoid the ground fissures and theground fissure activities will be harmful to the subway construction and safety operation.In this paper, according to the ground fissures survey data of xi ’an subway, analyzed theunderground water level distribution characteristics of different ground fissures. On the basisof this analysis, statistical and analysis the change trend of the different ground fissuresground water level along the direction of the ground fissures. Along the direction of theground fissures, the change trend of groundwater level and the topographical is not same;According to the topography background of xi ’an ground fissure, statistical and analysis thedistribution features of the underground water level near the ground fissure in the differentgeomorphic units, it is concluded that the ratio of the difference groundwater level is bigger inthe alluvial-proluvial fan and Residual loess tableland geomorphic, the ratio of the differencegroundwater level is relatively small in the loess tableland landscape geomorphic. Analyzedthe characteristics of unconfined water flow near the ground fissures, hanging side unconfinedwate when flowing through the ground fissure on head loss.Finally, the article analyzes the mechanism of soil compaction caused by groundwaterlevel change, and combined with the groundwater exploitation in xian, illustrates thatexcessive swabbing underground confined water has intensified the vertical activity ofground fissure. Cause ground fissure paranormal activity factor, one reason is the differentthickness of compressible stratum, anther is ground fissure destroys the integrity of thegroundwater flow system, strengthen the development of the local artesian water cone ofdepression, the different waterhead variation on both sides of ground cracks also has a lot todo. Finally,brief analysis the fall of unconfined water near the ground fissure can also causecrack formation pressure difference on both sides, exacerbating vertical activity of groundfissure.