Study On Analysis Of Slope Failure Mechanism And Controlling Design Of Ji'an-Dandong Cutting Slope

The controlling of the cutting slope has been a bottleneck problem inthe construction of speedway for a long time. Before the middle of1980s, the elementary rode was the main of rode construction. Thetraffic flow was lower, the deep cut and high fill was less, and theinvestment was lower. So the controlling of slope project wasn't themain project in the rode construction, and it is neglected always. Afterthe 1980s, the stability of slope became an important problem as theprosperity of the rode construction. As lack of research on thecontrolling measure of slope systematically, the incipient fault of theproject is developed. The slope instability can make the traffic break,even a lot of economic losses and bad social effect, at the same time,increase the cost of maintenance and controlling greatly.The cutting slope of rode in hilly and mountain area has manycharacteristics such as complex geological conditions, inconsistentscale, various failure form, dispersal terrene, and random environmentalfactor. There are two failure forms about the slope: whole failure andlocal failure. There are translational slides, rotational slides, andlarge-scale falls and topples which are the main failure forms about thewhole failure, and about the local failure, there are free falls, slumping,topples, block slide, rock debris or soil mass flow and so on. There aremany factors affect the stability of when excavating the cutting slope.The internal factors include strata lithology, geologic structure, rock andsoil mass structure, and the slope form, etc. And the external factorsinclude the water effect, engineering activities, weather conditions,weathering and plant growing, etc. After comprehensive survey andsystematical analysis, the stability of the slope is evaluated synthetically,and then the controlling measure can be determined appropriately.The inferior rode from Jian to Dandong is the vital communication lineconnected Jian city and Dandong city, 73km long. This rode is in thesouth of Laoling, on or near to the geosphere fracture zone of Yalu river,and this area is mountain terrain. Because of the complex geologicalconditions and the irrational construction in the early days, the landslides, falls and other geological disasters developed along this rodeafter in use from 2001 year. So it is very necessary to analyze thecharacteristic of the slope along this rode, and then adopt the usefulcontrolling measure.The slope instability along this rode can be divided into three failureforms based on field exploration. The first one is land slide, includingprogressive failure, traction failure, and wedge-plane slide of sand-shalewhich is hard and steep. The second is falling including graywacke,magmatite and metamorphic falling, and the macadam or soil falling ofsoft and hard rock. The last one is creeping failure of macadam and soil.Those failure mechanisms were analyzed based on themselvesengineering geology conditions, the effects of all sorts of factors to theslope were introduced and the main factors affecting the stability of theslope were found in this article.In order to determine the shear strength of slide surface, the testmethod and back analysis combined and was in use in the quantitativeanalysis of land slide, and different drainage rates were considered. Thefallings and creeping failures of macadam and soil had developed, butits scale is smaller, so considering the effect factors, the qualitativeanalysis was adopted. Those stability analyses provide a calculationbasis for controlling design.