Finite Element Analysis On The Maintenance And Strengthening Of Retaining Structures In High-altitude Regions

As the structure for stabilizing high fill subgrade and cut slope, retaining walls are quitecommon in highway engineering. Besides earth pressure, retaining walls in frozen area alsosuffer frost heaving force and thrust force by slope in melting layers, causing more partslosing and more unstability phenomena, which seriously affect the driving comfort and safety.So the reinforcement of those retaining walls is of great significance.Base on the conditioning of soil temperature, reducing the pressure and increasing thestructural resistance force, this paper proposes several temperature-conditioning measures,including increasing the thickness of wall, paving heat insulation material such as XPS orturf. Through modeling the transient heat exchange and three dimensional mechanical ofretaining wall, numerical simulation of thermal distribution and mechanical distributionwere conducted, thermal insulation performance and mechanical effects of each measurewere analyzed. Through modeling the equivalent heat transfer of heat-bar, its refrigerationperformance was researched, and also the thermal and mechanical effect of the compoundof heat-bar and insulation board. In consideration of earth pressure and frost heavingpressure, three dimensional mechanical model was set to analyze the strengthening effect ofbolt and optimize its properties. By using Monte Carlo calculation method, and taking therandomness of geotechnical parameters into consideration, the model of the reliability ofgravity retaining wall was set up, then the sensibility between different parameters andsensibilities were analyzed.The result shows that three measures raised permafrost tables differently, the thawdepth of three measures gradually increased in the order of paving heat insulation material,thickening the wall and paving insulation layer. The heat-bar’s transfer cooling process canbe divided into two phases-"cold storage" and "spread", the influence sphere of "spread"phase is larger, and using the influence range of "cold storage" phase-1.5m as its radius ofaction, besides, as the function of slide-resistant pile, hot bars can decrease the slopingthrust force impacting on the retaining wall. Increasing the length of the anchor rod isconducive to limit the retaining walls’ horizontal displacement, In addition, small-anglesettled anchor rod can effectively reduce the retaining walls’ horizontal displacement, and small-angle design is beneficial to both the axial force of the anchor rod and the retainingwalls’ stability. The results of reliability calculation are that the probability of retainingwalls’ stabilizing force is greater than the downward force is89.439%; the probability ofretaining walls’ stabilization torque is greater than the overturning moment is95.929%.After strengthening, the skip resistance and turnover resistance of retaining wall haveobviously increased.