Applied Mechanics and Materials Vols. 170-173

Abstract: Soil samples of slide body and slide zone are obtained to study the strength parameters from a landslide in Yunnan Province, China. Firstly, the basic physical properties of the two soil samples are measured. Then geotechnical tests are performed to study the variation law of strength parameters under different water content by using the automatic KTG triaxial shear apparatus. The results show that the cohesion of soils rapidly reduces with water content increasing, and slowly reduces when plastic limit attains, and it seems that a turning point appears at the location of plastic limit.The relation of cohesion with water content approximately conforms to the exponential function, and the relation of internal friction angle  with water content approximately conforms to the linear relation.

Abstract: China University of Geosciences (Beijing) has developed a dynamic compaction and compaction grouting (DCCG) method for groundwater flow control in Dalian. This method has been proven effective in dramatically reducing permeability in plain fill soil, and in granular or porous media. It has been successful used in many applications dealing with deep pit by coast. This paper presents the DCCG that has particular relevance in today’s pit construction marketplace by coast. Permeability can be improved by means of the DCCG. A brief introduction to the technique is followed by discussion of recent advances, illustrated by case studies of applications

Abstract: Hot dry rock is more and more appreciated as a kind of newly resource, which is up to the low carbon idea. Storage layer is the heat origin in heating system, is the exchange place for hot dry rock and water. So the temperature distribution tendency of the happening of storage layer and the heat exchange, the prediction for the service life of storage layer will affect the resource utilization and development. The paper uses one - dimensional simulate heat conduction formula based on FenDun mountain hot dry rock research, combined with deep rock parameters and heat conduction parameters of Shenyang to determine that using heat conducting research in storage layer of hot dry rock can simplify reservoir parameters for calculation. And then to get the temperature distribution discipline of storage layer of hot dry rock when hot exchanged.

Abstract: Expansive soil is a kind of high plastic clay which is more sensitive to changes of climatic and hydrogeologic conditions, and it has the character of swelling when watering and shrinking when drying out. Such repeated fluctuations from dry to wet induce irreversible deformation ,which will make the shear strength and internal friction of soil drop sharply and cause slope fracture. In recent years, abnormal climatic changes worldwide make foundation stability of expansive soil face severe test . Atmospheric influence depth can supply design basis for slope fracture of expansive soil. But in the situation of abnormal climates , the depth will exceed original design criterion and hazard engineering accidents will happen. Therefore, It has great importance in engineering application of studying influences of abnormal climates to engineering characteristics of expansive soil.

Abstract: In view of the randomness and fuzziness of the parameters of rock’s shear strength, first, use symmetric triangular fuzzy numbers which can reflect the interval features of parameters express the parameters of rock’s shear strength. Second, put forward to a new determination method for parameters of rock’s shear strength through least absolute linear regression based on symmetric triangular fuzzy numbers according to criteria of least absolute. Finally, the analysis of practical engineering computation and comparison to other methods shows that the new method is reasonable.

Abstract: This paper proposes a new partial-analytical consolidation coefficient calculation method as consolidation rate attenuation method based on the 1st-order series solution to one-dimensional Terzaghi theory. According to the consolidation rate attenuation curves, consolidation coefficient can be obtained by the linear attenuation part fitting. Least square principal is used to get fitting parameters of the extracted linear attenuation data by computer. This new developed method has rigorous formula which avoids mapping human factors, the effect of initial settlement and secondary consolidation. By the evaluation comparison of different methods, this new method is accurate, which also means the test process will be speeded up

Abstract: The negative frictional resistance for large-diameter caisson pile is very important to the stability of pile foundation. Lots of engineering projects speak volume for the signal influence of negative frictional resistance on foundation pile. Therefore, it is very necessary to analyze the generation mechanism of the negative frictional resistance on the large-diameter caisson pile and the mechanics characteristics for pile-soil in the coastal under consolidated soil environment. Base on the generation conditions and basic characteristics of negative frictional resistance, the generation conditions and generation mechanisms of negative frictional resistance for large-diameter caisson pile are analyzed on condition of under consolidation for saturated soft clay. Based on the linear softening model for the pile lateral face and hardening model for the tip of the pile, the analytical solution for negative frictional resistance based on the elastic theory was proposed. According to the one-dimensional consolidation theory, the analytical equations are attained when the pile-surrounding soil and pile-end soil is in different conditions. At last, the rationality of analysis process is verified by an engineering case.

Abstract: Based on the analysis of the main factors which influence the cost of the anti-slide pile, a mathematical model was proposed. In this model, the expenditure of anti-slide pile construction was taken as the objective function, and the constraints covered the strength and stability of anti-slide pile, the strength of the soil mass or rock mass and some other demands. A program was developed for the anti-slide pile geometry sizes determination using stochastic search algorithm. With the aid of this program, appropriate geometry sizes of anti-slide pile with lower cost and enough safety could be automatically found. An example showed that the cost of the anti-slide pile could be decreased in contrust with conventional design method.

Abstract: The effect of detonation gas upon rock fracture is the cross-frontier research project of fluid dynamics coupling and rock dynamics of crack dynamic growth, having the important scientific significance and explicit application value. In the process of detonation gas driven fracture growth, the varying law of the denotation gas pressure distribution in cracks is inter-influent with the geometric morphology variations in crack growth. This paper analyzes the denotation gas flowing behaviors, establishes the flowing model for denotation gas in rock cracks and the models for the rock crack dynamic response. Also suggests the fluid-solid coupling model for the denotation gas flowing, rock crack response and the numerical model for simulating crack growth driven by the denotation gas. The simulation program is developed on the large-sized rock engineering finite element software (FINAL platform). This numerical analysis platform is used to carry out the systematic numerical experimental study of several main influencing factors of core problems concerning pressure fracture length.

Abstract: The plasma in the eolian sand, included silt particle and clay particle, change easily and hugely. For studying their influences on the strength property of eolian sand, mixed silt particles and clay particles into eolian sand in different proportions to measure the internal friction angle and cohesion under different forming and testing conditions. The result indicates that: for the same kind of test specimen under different test types, the changes of cohesion and internal friction coefficient are regular. For the same test type, the changes of both cohesion and internal friction coefficient of different test specimens are regular. Generally, when the content of silt particles and clay particles is lower than a certain value, the cohesion and internal friction coefficient increase accordingly and rapidly along with the increase of silt particles and clay particles; after the content of silt particles and clay particles is larger than this value, the cohesion and internal friction coefficient increase slowly or decline along with the increase of silt particles and clay particles. The change range of this value is approximately between 45%～65%, the content of silt particles and clay particles. For the purpose of this test, as to the transition of test specimens from typical sandy soil to fine grained soil caused by the increase of silt particles and clay particles, the change point of strength is at 45％ approximately, which is basically consistent with the compacting test and CBR test, etc.