Relationship between the Shear Strength and the Depth of Cone Penetration in Fall Cone Tests

The determination of liquid limit is of great significance in the engineering classification of soil and the selection of the control standard of highway subgrade packing and compactness. Based on the research achievements of many scholars on the relationship between the shear strength and the depth of cone penetration in fall cone tests in the liquid limit tests, the process of penetration was analyzed according to the Law of Conservation of Energy, and the expression of K was derived. Then, the expression was verified by the experimental data of different scholars and the existing data of various countries and institutions. And, the results were also compared with those obtained by the previous scholars using limit equilibrium theory. The results indicate that the new expression is in good agreement with the experimental results. K can be predicted well. And so, the shear strength can be calculated based on the depth of cone penetration, and then, the experimental value of the shear strength can be compared with the calculated value through laboratory tests. The influence of cone weight and cone angle on the shear strength calculation was analyzed. In addition, the liquid limit index of different standards was discussed based on the expression of K, and suggestions on how to achieve relative combination of different codes and standards were raised, which was very helpful for international communication.

Analysis of Obstacle of Development and Application that Coal Gangue Used in China Road Engineering

Coal gangue as road engineering material can sovle the problems of energy saving and environmental protection.Experimental datas of grain size distribution,crushing value,slake durability index,expansivity,liquid limit index,plastic limit index and water absorption showed that its own characteristics are in line with the requirements of road engineering materials. There are successful cases of application of coal gangue in road constructions both here and abroad. Principal component analysis is used to identify four major factors of coal gangue applications in road construction.Put forward 5 urgent problems to be solved and give a few corresponding suggestions.

A Criticality Assessment Method for Power Transmission Lines in Power System

Analytic Hierarchy Process (AHP) is presented in this paper to measure the relative criticality for transmission lines, considering the changes of power system’s status about transmission lines overload, central buses voltage over-limit and transient stability. At first hierarchy structure is modeled, and then indexes of criteria Layer including transmission line overload index, central buses voltage over-limit index and transient stability index were presented. The simulation results show that, the AHP assessment method can give a full consideration to transmission lines’ function, which of huge significance for identifying critical lines and increasing the security of power system.

The Daxinganling Island Taliks Sheet Permafrost Feature

In order to study the features of permafrost in Daxinganling, based on t he methods of field investigation and borehole drilling, as w ell as theoretic analysis and the effects of frozen soil geological conditions, topography features, frozen soil type and permafrost classification the freeze-thaw depth(m),main physical indicators of the Frost soil, natural water content, plastic limit Liquid limit index were analysis .the thaw settlement and frost heave were studied in this paper.