Study On Affect Of Garbage Soil Parameters On Deformation Of Foundation Pit Supporting Structure Metro-north Station In Qingdao

Subway construction is the trend of underground space development in the newcentury. Nowadays, subways in Beijing, Shanghai and some other first-tier cities havealready been opened, and subways are under construction in more than ten cities suchas Qingdao and Hangzhou, it will be the new page of railway construction in thecentury.Subway is always constructed in impacted areas and districts wheregeological conditions are complex. This makes it very hard to dig out a large amountof station foundation pits, causing a lot of technical and engineering problems, so it iscrucial to study the foundation pits engineering under complex geological conditions.The subway foundation pits of Qingdao Subway North Station are studied in thispaper, and the monitoring of the foundation pits and numerical stimulation areexplicitly introduced, allthose are serve for Garbage soil parameters research.The Qingdao Subway North Station is adjacent to Jiaozhou Gulf and located in arefuse landfill. Nowadays, there are not many projects are constructed under thisgeological conditions, so very few monitoring data are available. The Subway NorthStation of Qingdao is the object of study in this paper.Firstly, according to themonitoring scheme, real-time monitoring are applied to the diaphragm wall’s deeplevel displacement, ground settlement of surroundings in the foundation pits, stealstrut axial force and some other items. The monitoring results are analysed under thefirst-class monitoring request. Secondly, geological numerical stimulation softwareplaxis2D is used for the foundation pits stimulation, based on the monitoring reportand design parameters, we can get the ideal model. After analyzing the differencebetween the ideal model and real foundation pits deformation by comparing with themonitoring data, we reached the following conclusions: The design parameters are tooidealized, the pipe body displacement and the ground settlement are smaller comparedwith the monitoring data, this is mainly because we didn’t take the particularity ofconstruction waste and house refuse miscellaneous fill into account. Rheologicalphenomenon is the result of the high vacancy and low load resistant of miscellaneousfill and the construction settlement is also not taken into account. Lastly, after usingthe trail method to approach the foundation pits’ value, the soil modulus and Poisson’sratio of the miscellaneous fill are adjusted, and then we got the foundation pits’deformation model. Next, by analyzing the drilled pile’s horizontal displacement, pileblock displacement and ground settlement after the adjustment, we found that thedeformation value is more fitted to the real monitoring value, so the adjustment ofparameters is achieved.Foundation excavation pit deformation and pit the control of the surroundingenvironment has become a key technology of foundation excavation. article researchthe Metro-North station pit deformation from the three aspects of simulation, theoryand engineering.Then reach the following conclusions: (1) The value of monitoring gradiented.The initial stage of pit excavation,envelope system deformation stable pit is generally a safe state; the monitoring valueschange significantly with the excavation of the pit,; the end of the foundation pitexcavation to padlayer is laid, the stability of the various changes in parametersappropriate to reduce the frequency of monitoring.(2) Narrow excavation space, reduce bare soil exposure time can reduce thedeformation of the support structure. During excavation to be appropriate to reducethe excavation space and shorten the time of exposure of bare soil in the excavation.(3) Bored pile horizontal displacement showing the varies.Undergroundcontinuous wall foundation pit variation curve generally shows semi-hyperbolic shape,Pit cushion pouring to the roof removed, the wall displacement is relatively stable;diaphragm wall depth of excavation of foundation pitdepth, the maximumdisplacement is related to both the ratio of the size of the underground continuouswall.(4) Pile soil mass settlement show a certain regularity.Peripheral surfacesubsidence apparent settlement of the valley, the settlement range and the excavationdepth, the width of that settlement of the surrounding soil is generally twice theexcavation depths; operating heavy machinery and the construction site of heavydebris accumulation (such as reinforced accumulation) a great influence on surfacesubsidence.(6) The overall variation of the spreadsheet approximation method to adjust theparameters of the garbage miscellaneous fill, adjust parameter model of displacement,stress change in the actual monitoring results coincide, in line with the pit.Reasonable and reliable to select the construction process and constructionparameters, will be able to pit design scientific, quantitative, consider thecharacteristics of the pit at different stages of construction, and thus can reasonablyregularly construction pit weeks of soil stress path and soil stress changes in the stateof the complex into a pattern.