A Water Stop Technology Of Deep Foundation Pit Near The River

The sealing up of excavation construction is not only a key point, but an inevitabledifficulty. In the process of construction, the excavation often appears serious leakageand even collapse caused by improper handling, which cause great negative influence inthe social and project loss. So for the sealing up of excavation construction with greatrisk and difficulty near the water, it is important to adopt proper and scientific treatmentin the construction of sealing up in the excavation. However, at present, the study on thetreatment technology of sealing up in the excavation near the water is rarely seen athome and abroad, and most construction scheme are based on the specific project,which has not general employing. So it is necessary to put forward a correspondingprocessing method through the system analysis. The paper based on the typical projectand carry out the basic research on the sealing up of excavation near the water. Themain contents of the paper are as follows:(1) The advantages and disadvantages of existing treatment technology on sealingup of the different types of foundation pit near the water are systematically analyzed.And on this basis, the processing scheme on the sealing up of excavation near the waterunder different conditions is provided.(2) Based on the theory of saturated-unsaturated seepage groundwater, a series ofnumerical analysis is carried on by the software GeoStudio. The influence of the depth,the distance to the excavation, the thickness and the permeability coefficient ofwater-tight screen and the soil to dewater in the step-slope excavation and leakingstoppage of excavation with water-stop curtain. Then in the basis of thenumerical analysis results, the influence of the changing of groundwater level caused bythe position of water-tight screen to the slope stability of excavation is discussed.(3) Applying the research results of the treatment technology on sealing up of excavation with water-stop curtain to the deep excavation engineering of subway inNingbo. And considering the characteristics of the project, the construction parametersof high pressure sprinkling stake are provided and the quality control technology onjoint construction of diaphragm wall is improved, whose rationality and reliability areassessed by water permeability test, core test, ultrasonic testing and the monitor ofleakage.The results show that the proposed scheme of two water-resistance processescan satisfy the water-stop requirements of the deep excavation near the water. By usingthe method on the premise of better quality control in the construction, the enclosuresystem of excavation has not obvious leakage generally, which can increase the safetyof excavation greatly.