Study On The Influence Of Construction Sequence Of Multi-level Fill High Slope On The Displacement Of Supporting Structure And Slope Stability In Loess Region

Based on the unstable slope support project of Baidaoping,Chengguan district,lanzhou city,this paper studies the displacement and slope stability of the multi-level high fill loess slope after the construction of soil filling and supporting structure according to different-construction sequences.Firstly,the slope stability analysis method and the slope supporting structure calculation method are described.Secondly,combined with the research direction of this subject,the existing slope stability analysis methods and slope support structure calculation methods are compared,and it is considered that the use of numerical analysis method for the study of slope stability after the construction of different-construction sequences has certain feasibility.In order to achieve the research objectives,the following tasks are mainly carried out:?1?Sampling on the construction site and conducting indoor tests to obtain the parameters of the filling soil mass and the original slope soil mass,so as to meet the requirements of material parameter assignment of indoor tests;?2?Select the original slope section with high applicability at the construction site,and install monitoring sensors according to the construction site;?3?Combined with the construction method,FLAC^3D software was used to study the slope stability and horizontal displacement of the slope support structure at each stage and after completion of the construction by using three construction methods of3 meters of support,6 meters of support,and 12 meters of support;?4?A comparative study was conducted by combining the monitoring data of the construction site with the calculation results of model tests.After the above experiments and experimental data research and analysis,the main research conclusions are as follows:?1?In this study,the failure to timely stretch the anchor cables of pile-slab wall leads to the large horizontal displacement of the upper part of the pile-slab wall,which is the main reason for the parabolic distribution of the soil pressure distribution on the back of the pile-slab wall with small middle ends;?2?In the actual project supported by this project,the earth pressure on the back of pile slab wall and the horizontal displacement of pile roof beam will be affected by temperature change;Within a certain temperature range,the greater the temperature difference between day and night,the greater the earth pressure difference on the back of retaining wall.After the freeze-thaw cycle of the slope soil in the loess region in spring,the soil structure changes and the soil strength decreases relatively.When the slope supporting structure is under elastic stress,the displacement of the slope supporting structure may show negative growth;?3?Both indoor simulation test and on-site real-time monitoring test reflect that with the influence of slope soil filling height,the influence of topsoil filling construction on the soil pressure or displacement on the back side of pile wall of first-stage supporting structure gradually weakens;Soil filling and supporting in time can effectively control the overall horizontal displacement of slope supporting structure and soil mass;In the actual project supported by this project,in the slope section position studied in this project,the tension crack at the top of the original slope may appear at the position 9¹1 m away from the top line of the slope;?4?Timely support structure construction should be carried out in the process of filling high slope soil and supporting structure construction;When there is a prestressed anchor cable supporting structure in the slope supporting structure,the prestressed anchor cable should be stretched in time,which has an important control effect on the displacement of the lower supporting structure caused by the upper filling soil;Soil filling is as important as slope supporting structure construction in high slope filling engineering.At the same time of slope soil filling,timely construction of slope supporting structure can effectively improve the degree of cooperative work of slope supporting structure and ensure the safety and stability of slope.For the slope abutment and filling engineering,the horizontal displacement of the original slope top and the filling slope top can be effectively controlled by using the construction method of side filling and supporting.When there are buildings or structures on the original slope top or the top of the filling body,it is suggested to carry out the construction according to the construction method of side filling and supporting;?5?The same slope shall be constructed in different construction sequences,and the construction method of side filling and side supporting can effectively improve the safety of the slope;Therefore,in the design of multi-level high fill slope support engineering,which is consistent with the foundation pit engineering,the possible dangerous working conditions in the construction process should be considered,and the construction process should be put forward in the support structure design stage.