Durability Studies Of Underground Structures Under The Condition Diaphragm Wall Laid With Geomembrane

Leakage problems of diaphragm wall have become increasingly prominent with the Application of foundation pit in the city. As a part of the underground structure, the seepage controlling and durability of diaphragm wall has became a growing concern in the current situation of the industrial city which can not be ignored by the situation of acid alkali resistance and corrosion resistance. Currently, researches mainly concentrated in the field of leakage control, reasonable form selection of joint to adapt to the engineering geological conditions and working conditions and leakage stoppage while researches concentrated on The whole diaphragm was rare.In this paper, a kind of diaphragm wall construction technology cling to geomembrane is put forward to make up the shortage of current technology which applies to the complicated hydrogeological condition. This technology can greatly improve the effect of seepage controlling and the durability of diaphragm wall.Based on this, the main content and research results of this paper are as follows:(1)Introduced the construction technology of diaphragm wall laid with geomembrane construction technology in detail, and to make choices in The geomembrane, durability, and thickness for the construction technology characteristics:the material thickness of the HDPE geomembrane is 1.0～1.5mm,and the structure is two pieces of cloth and a membrane.(2) Maked the comparative experiments diaphragm wall with geomembrane and diaphragm wall without geomembrane in order to simulate the engineering practice,we will get the concrete specimens of the diaphragm wall with geomembrane and seepage resistance grade improved from P8 to PI2; geomembrane in good condition is no water percolation; geomembrane under small scale broken will not make the anti-seepage effect of the geomembrane completely ineffective,and it with closely-linked concrete make a large part of anti-seepage effect.(3) Analysising the leakage caused by diaphragm wall mud, analog infiltration pore water penetration when Mud holes exist in the wall by finiting element software ABAQUS. The results show great harm that mud holes exist in the wall, and the construction technology of diaphragm wall laid with geomembrane in this paper can largely reduce the harm of mud existing the wall.(4) The improvement of the diaphragm wall’s durability after laying with geomembrane is investigated by targeting the environment, mechanics and construction factors in these areas.(5) The relationship between permeability and durability of the underground structure is analyzed, and the permeability index is proposed and tried to evaluate the durability of the underground structure based on the diaphragm wall laid with geomembrane.The results show that the underground structure has sufficient durability.