Assessing model of highway slope stability based on optimized SVM

Considering the geological hazards attributed to the highway slope,using a common simple model cannot accurately assess the stability of the slope.First,principal component analysis(PCA)was conducted to extract the principal components of six factors(namely,bulk density,cohesion,internal friction angle,slope angle,slope height,and pore water pressure ratio)affecting the slope stability.Second,four principal components were adopted as input variables of the support vector machine(SVM)model optimized by genetic algorithm(GA).The output variable was slope stability.Lastly,the assessing model of highway slope stability based on PCA-GA-SVM is established.The maximal absolute error of the model is 0.0921 and the maximal relative error is 9.21%by comparing the assessment value and the practical value of the test sample.The above studies are conducive to enrich the assessing model of highway slope stability and provide some reference for highway slope engineering treatment.

Stability evaluation and protection of slope for Laosongling-Yanji Highway

The authors analyzed the engineering geological characteristics of the slope of the study area (K75+840-K76+340). Two typical cross-sections have been chosen to analyze the failure modes after the excavation of the highway. Different types of the failure modes have been calculated and analyzed. The results show that some dealing methods have been advised to ensure the stability of the slopes.

Dynamic Design and Construction of Highway Cut Slopes in Huangshan Area, China

Deformation and failure of high slope impact the construction and operation safety of highway in the mountainous areas. The deformation and failure are mainly caused by poor design which normally has not well combined with the geological conditions and unplanned construction. Therefore, effective design and construction management should be conducted for ensuring a successful construction without damage and risk. In light of the reality of high slope construction along highway in the Huangshan area, this paper proposes a technical procedure for dynamic design and construction management of high slopes along highway in the mountainous area. The proposed construction management scheme is divided into three phases, i.e., 1) design phase, 2) preparation phase of excavation, and 3) construction phase. During the design phase, experiences and lessons learnt from the design and construction of other high slopes along highway in the same region are summarized. The number of slopes and slope height should be optimized from the aspects of route selection and route form. During the preparation phase of excavation, "Excavation Permit Management System" should be adopted, and construction scheme should be made by the construction unit, then the scientific research and design unit determine whether it guarantees slope stability and makes optimization measures. During the construction phase, the scientific research unit would make proposal of optimization design, and apply the achievements of scientific research into practice through common efforts of various units based on the understanding of excavation and investigation. The management system mentioned above is adopted to conduct dynamic design and construction management for more than 90 slopes along the Huangshan - Taling - Taolin Expressway, and successful results of application have been achieved.

Dynamic Response of Double-Sided Loess Slope under Vehicle Load

In order to verify and study the dynamic response law on the double-sided loess slope under the action of the waves generated by automobile traffic,we select a double-sided loess slope from the long section of Anzi Road as the research object.Both field investigations and on-site monitoring processes are conducted,for the purpose of providing robust basis for road protection in these conditions.In detail,vehicleinduced vibration signals are different according to different vehicle types,speeds,as well as positions,and thus are collected,respectively.Based on the statistical analysis of the signals,the vibration response law and frequency spectrum characteristics of the slope are summarized.The results show that:①The dynamic response of the doublesided loess slope increases as the vehicle load increases,and the strong vibration response area is located in the middle of the side slope;②When the vehicle load is small,the vibration wave amplification effect is obvious.On the contrary,when the vehicle load is large,the vibration wave amplification effect is weakened;③The spectrum distribution of the X-direction wave is single-peak shape,and the dominant frequency is concentrated in 30-50 Hz;the frequency spectrum distribution of the Zdirection wave shows a multi-peak shape,and the dominant frequency is concentrated in 20-180 Hz;④The vibration wave propagates in the slope.The frequency change shows little correlation with the type,speed and position of the vehicle,and instead,it is mainly determined by the slope itself.This study reveals the dynamic response on doubled-sided loess slopes and provides both theoretical and practical significance for the road protection in such situations.

A Pull-Out Test Study on the Working State of Fully Grouted Bolts

The present study examines the working conditions of fully grouted bolts used for the construction and expansion of high slopes.On the basis of a pull out destructive test,the work load and the ultimate load are obtained on site,and the Flac3d numerical simulation method is employed to determine the axial force distribution and the effective anchor length.The test results show that(1)the Q-S(load-displacement)curve of the bolt displays a certain degree of deformation coupled with the creep of the surrounding rock;(2)the working load of the bolt is closely related to the sliding deformation trend of the slope,while the ultimate load depends on the design parameters of the bolt and the lithology of the slope;(3)the distribution of bolt axial force is characterized by a single peak along the bolt length and the effective anchorage length of the bolt is 3 m;(4)after 20 years,the bolt’s ultimate load has a maximum loss of 31.94%.