Research On Vibration Intubation Technical Parameters Simulation Based On The Freezing Method For Cut-off Wall

Seepage interception project is an important part of cofferdam project in thefield of water conservancy construction. Only seepage interception project is wellcompleted, can safety and reliability of cofferdam project be guaranteed. To createnecessary conditions for successive projects, main foundation ditch must beconstructed first. So the good or bad of impermeability in cofferdam determinesdirectly dry work and quality of dam project. Currently such methods as concreteunderground continuous wall and high-pressure jet grouting cut-off wall are appliedto construct cut-off wall. But these methods have some disadvantages ascomplicated processes, high expense, long period, serious pollution and so on. Forimproving these disadvantages vibration intubation technique coupling freezingtechnique is creatively applied to construct underground cut-off wall in this paper.Freezing technique is a green construction technology which has manyadvantages as adaptability, impermeability, little environmental pollution. To reducethe temperature of soils, soil formation containing water is froze in order to increaseintensity and stability of freezing formation. Moreover the relation of undergroundstructure and underground water is cut off in order to conveniently accomplishtunneling construction, vertical mine construction and excavation of foundationengineering. And vibration intubation technique is the crucial method that freezingtechnique is applied to construct underground cur-off wall before. The soil formationis compacted to form a hole through vibratory hammer striking the tube. Thenfreezing pipes are transported to the bottom of the hole through central passage ofthe tube in order to freeze soil formation and form underground frozen wall. Toarrange position of the holes underground permafrost cur-off wall is accomplished. This research is supported by Jilin technology development project named “TheResearch on construction of cut-off wall by freezing method”. According todevelopment status of freezing technique and vibration technique, based on theory,actual application and computer simulation the combination methods are applied toanalyze the research that the different vibratory parameters and size parameterseffect on soil formation. The specific research contents contained three parts:(1)thetube imposed vibratory load effects on soil formation by simulation softwareANSYS/LS-DYNA;(2)To change exciting force and vibration frequency, thevibratory tube effects on soil formation and rate of penetration;(3)To changediameter and wall thinness of vibratory tube, the tube effects on vibratorydisplacement in soil formation. Through above simulation and analysis, there arethree conclusions.(1)The principle factors effected on vibrating into soil formation are excitingforce, vibration frequency and structure parameters of tube.(2)In the same soil formation condition, whether increasing exciting force orvibration frequency, the speed of vibrating into soil formation can be increased. Thechange of exciting force more greatly effects on the speed of vibration.(3)In the same soil formation condition, the change of structure parameterscontains the change of diameter and wall thinness of vibratory tube. These changescould reduce the displacement of vibration. But the extent of reduction is little.Though vibration intubation technique and freezing technique have developedmaturely, the two coupling technique applied to construct underground cut-off wallis a new technology. But this technology is not widely applied in the process ofconstruction. Further exploration and practice will be carried out in the future.