Study On The Settlement Of Building Prediction And Supporting Structure Deformation During The Excavation Of Footing Groove

Abstract:This thesis introduces the current situation both at home and abroad during the excavation of footing groove,and explains the deformation theory of footing groove and the analysis of space-time effect.Zhonglv technical Building in Shenyang is taken as the main research object,and also taken some methods,such as Geological Drilling,Engineering Geophysics,The sample in live,Field test,Indoor soil test and so on,to study and analyze the stratum situation;taken the method of "dynamical design,information-oriented construction" to design and construction the footing groove;and also taken high-precision total station and electronic level to monitor the displacement of top bore and the settlement of building prediction regularly.In today's deep excavation engineering,the importance of settlement prediction is becoming more prominent.In order to control the impact on the settlement of building during the excavation of footing groove,this thesis based on artificial neural network-based BP,used its powerful nonlinear mapping capability Settlement of a deep pit surrounding buildings prediction model is established.Training in the use of the network on the basis of the measured data,the largest settlement of the pit surrounding buildings is predicted.The results showed good agreement between the measured values and forecast values,showed the effectiveness of the method for forecasting the deformation of deep footing groove.In this paper,Zhonglv building in Shenyang is taken as the major excavation works for the study,ADINA non-linear f'mite element software for a research tools,a 3-D f'mite element model is established,the actual value of the simulation are similar to monitor deformation,deformation data are acquired in post processing module in ADINA,inspected the space effect of the footing groove engineering.In accordance with the actual soil modulus,part of the pit model is established by changing the soil and structure parameters,and also obtained the impact law of supporting structure deformation:(1)In the soil parameters,the changes of deformation modulus and Poisson's ratio have great impact on supporting structure deformation,cohesive strength and friction angle have not very obvious influence,but the cohesive strength has more impact than friction angle(2)This project can divide into four levels,among them first level,second level,third level are above on mentioned,which has little impact on supporting structure deformation when change the stiffness.The fourth layer of soil can offer the passive pressure to supporting structure,it has more impact on supporting structure,when change the stiffness.(3)It has more impact on supporting structure,when the embedded depth changed in the relatively simple range;It has little impact on supporting structure,when it increased to the certain extent(as 4m).For the pile-anchor support which the excavation depth is 11m,the embedded depth designs 4m generally.(4)Changing the diameter of pile can change the stiffness of supporting structure.Increasing the diameter can decrease the deformation of supporting structure,when the diameter increased to the certain extent has little impact on supporting structure.For the pile-anchor support which the excavation depth is 11m,the diameter designs 0.6m generally.(5)Increasing the angle of anchor can increase the deformation of supporting structure.The support deformation of the anchor which the angle is between 10°-25°is small.During the range, it is not only convenience for the construction,but also can enhance the security of the project.(6)The deformation of anchor has more impact on the deformation of supporting structure. When the anchor closes to the top of pile,the deformation of supporting structure has little changes.The situations of two rows of stocks are the same as a row of stocks,and obtained from the curve graph out of shape,it plays a key role in the position of the first row of stocks.In order to the construction actually,generally designed to leave the earth's surface 4m.(7)The longer the anchor,the smaller impact on the deformation of supporting structure.For the pile-anchor support which the excavation depth is 11m,the length designs 11-14m generally.At the same time,this thesis adopts the data processing method in the real experiment--Orthogonal Experimental Design.Utilizing the deformation of supporting structure which is obtained from the model of finite element simulation as the experimental marriage partner,and basing on the appropriate level of the factor figure,we select the suitable orthogonal array to carry on the numerical simulation experiment.According to the Range analysis,Variance analysis and the analysis of Contribute effect picture,among the greatest factor which influence the displacement of supporting structure.Parameter sensitiveness which is from great to light arranges: the deformation stiffness,the deformation of anchor,the diameter of pile,the embedded depth,the length of anchor,the angle of anchor,Poisson's ratio,the cohesive strength and the friction angle. The deformation stiffness of soil,the deformation of anchor,the diameter of pile,the embedded depth,and the length of anchor have significance influence on the deformation of supporting structure.The angle of anchor has general influence.Poisson's ratio,the cohesive strength and the friction angle has not obvious influence.