The Research On Grab Thin Concrete Diaphragm Wall And Its Applying In Levee Strengthening Of Changjiang River

Grabbed thin plastic concrete diaphragm wall(abbreviated as GTDW hereinafter) is a new technology of vertical anti-seepage developed for levee strengthening of the Changjiang river. Considering there are numerous important sections along the levee of the Changjiang river and a commonly existence of dualistic geologic conditions in it, GTDW has a stronger adaptability than other anti-seepage technologies and will get a more reliable assurance on wall quality and anti-seepage effect.GTDW, developed based on the conventional concrete diaphragm wall, has brought an important technic and economic change by decreasing its wall thickness which is now only 30 cm. In adopting some trenching skills, such as pure grabbing , primary trenching, etc., GTDW has done a good job in resolving the problem of trenching through the sandy or pebbled stratums of the Changjiang river levee, furthermore, the trenching efficiency has been raised greatly.During the trenching procedure, until concrete casting is taken, it is very crucial to maintain the stability of the trench wall, which relatives closely to geologic conditions, particle size, groundwater state, trenching skills and so on. It is very complex to analyze the relationship between the stability of trench wall and the mechanism of slurry stable wall which has been proved to be the most effective way to stable the trench wall. This article , against clayey and unclayey stratums in the Changjiang river's levee, makes a complete analysis on the above-mentioned relationship, in opinion of geology and hydraulics. Thus analysis makes theoretic support and clear learning to the slurry stable wall.To be the wall material of GTDW, comparing with the conventional concrete diaphragm wall, plastic concrete has a much lower elastomeric modulus that approaches to that of the around soil. As a result, the deformation of the plastic concrete diaphragm wall under pressure will be similar with that of the around stratums. The stress state of theIIIdiaphragm wall is greatly improved and thus improvement will make it easy for the diaphragm wall to fit the stress changes by the thinner of wall or the frequent changes of the water level.A reliable way to connect wall sections is the key to get a continuous wall with good quality. GTDW makes a well resolution on the connection of 30cm-thickness wall by using the skill of case connecting, which is a typical character that GTDW has much more advantages than other anti-seepage techs.GTDW has learn a lot on quality checking methods and criterions from conventional concrete diaphragm wall to form it selfs reliable quality checking system and correct, simple quality criterions. Based on the conclusion to the above, this article raises some new methods and fresh opinions for GTDW about the quality control and check which has been verified in practice.GTDW is a new practical tech for vertical anti-seepage. The tech has been utilized widely in levee strengthening of the Changjiang river and a good result has been gotten. Connecting closely with and concluded completely to the practice of the Changjiang river's levee strengthening, this article shows readers the advantages, reliability and the practical value of GTRM.