Xiao Hong Bai

The Influence of pH Value and SO42- Concentration on Strength of Cemented Soil

The pH value and SO42- concentration in corrosive environment may affect mechanical property of cemented soil inturn to cause some serious damage to structure. The results of tests show that the unconfined compression strength is decreasing with the increase of H2SO4 solution concentration, increasing with the increase of pH value. The pH value is increasing and the SO42- concentration is decreasing with the increase of corrosive time. So it is concluded that compressive strength is closely rated with the pH value, SO42- concentration of corrosive environment and corrosive time. Finally a equation is set up based on the relationship of compressive strength and factors affected, which contain the reduced coefficient of compressive strength, pH value, SO42- concentration and corrosive time. The calculated and measured values are close so that the equation could be used in practical design for reference.

The Experiment of Deformation and Internal Force of Soft Pipeline Caused by Subsoil Settlement

Through the model test in soil slot,the process of deformation and destruction of soft pipeline caused by subsoil settlement is simulated and observed in lab. Based on the experimental data, the curve as the internal force of pipeline is first drawn out and discussed, in turn the characteristic of stress distribution and destruction rule of pipeline are analyzed and summarized, which may be referred for designer to take appropriate measures. The experimental results show that the internal force and deflection of the pipeline increase with the depth and width of the hole below the pipeline. When the hole depth (h)/ pipeline diameter (D) =2.5, internal force and deflection changes only associate with the width of the hole (b). And when b/D =6, the pipeline can not work normally and even be destroyed. The experimental conclusion can provide the basis for the security of underground pipeline.

The Ac Impedance Characteristics of Soil with Different Water Content

As an important and mature technology of researching material properties, ac impedance spectroscopy has successfully applied in many discipline except for soil research. Based on the experiments using TH2828A wide frequency LCR meter (from 50 to 106 Hz), the ac impedance characteristics with different water content of soil had been discussed. The results fully illustrate that the ac impedance is one of the basic property of soil,and the value of ac impedance parameter can be reflected the water content quantitatively. when using the fixed frequency to measure ac impedance of soil, it is most suitable as the frequency equals 104 Hz.The measure method of ac impedance have no effect to physical properties and internal structure of soil.

Deep Excavation Caused by the Impact of the Adjacent Buried Pipeline Destroy the Analysis

The subject of Foundation Excavation near the buried pipeline line. Compared with each other using a scale model of the buried pipeline foundation excavation factor of the vertical displacement, and connected with the buried pipeline displacement of both ends of the fixed elastic beam theory; analysis of the factors affecting the displacement of buried pipelines, the good agreement of the theoretical results with the scale model test value.

A Trip for the Works of Epidermis Artists

Herzog and de Meuron were 2001 Pulitzer prize winners. Their buildings are famous because of the unique and amazing epidermis. In their representative works, there are two major ways to create and form epidermis. The first one is learning from the surrounding context and environment, and the second is thinking about the features of architectures. This paper, through the investigation of six of their major works: Dominus Winery in California of the US(1998), De Young Museum in San Francisco (2004), the library of Brandenburg Industrial University in Germany, the Tokyo Prada flagship store in Japan, Munich Allianz Stadium in Germany, and Laban Centre for Contemporary Dance in London, summarizes the main methods of H&dM.Architecture surface processing is becoming more and more concerned by the construction industry and the viewers. H&dMs methods of design provide our use for reference. Let us look forward to their next new work.

Taiyuan Underground Pipeline Testing and Analysis of Deformation and Failure

GEO-groove simulation experiment is applied to imitate the Taiyuan soil subsidence in pipeline base and side by soil loss, which eventually leads the pipeline to be deformed and destroyed. The pre-damage standard is set up though analyzing test statistics and drawing it’s sedimentation and damage curve. The damage standard of sewage line is achieved through setting up a very pilot model to the test and analyzing it’s bearing force characteristics, and according to the gotten sedimentation curve of the test, damage characteristics and mechanism of sewage line is analyzed , thus will give the designing and application of pipeline of testing and theory basement, so as to take measures to protect pipeline in practical situations, establish early warning system to pipeline, and guarantee it’s regular service.

Q3 Loess-Like Silt Bearing Capacity of Foundation Partition Statistical Analysis in the Shanxi Yuncheng

Currently it is still a lack of reliable evidences on the evaluation of the bearing capacity of foundation in highway construction of Shanxi Province. Mainly reason is that the method widely used to determine in bearing capacity of loess foundation in building structures is not completely suitable to length and wide range of highway subgrade project. Because Shanxi loess region terrain is very complex, the capacity of Q3 loess-like silt in Yuncheng of Shanxi is collected and analyzed, based on statistics of a large number of bearing capacity from site loading tect. A linear regression relationship is established between loess foundation bearing capacities and water content, liquid limit, void ratio. Another linear regression relationship is established between saturation and liquid limit void ratio . Meanwhile, it compares these two sets of linear regression relationship with the measured bearing capacity and the carrying capacity by specification. Applied result show that the relative errors of the bearing capacities computed by the formulas are less than 10%, compared with other standard methods to determine the loess bearing capacity. It is significantly improvement for meeting the requirements of the highway construction.

Experimental Research on Compression Characteristics of Compacted Loess

A series of compression tests were conducted on the samples taken from compacted soil site in Lulling, in order to investigate the compressibility of compacted loess in different water content and different compaction energy. Through statistics analysis of the testing data, the stress-strain curve of compacted loess could be expressed with Hyperbolic form. And the relation between initial tangent modulus and water content change coefficient was founded by introducing the water content change coefficient. The result shows that at the same compaction energy, the initial tangent modulus decreases and the ultimate strain increases as water content increases; while at the same water content change coefficient, the initial tangent modulus increases and the ultimate strain decreases as compaction effort increases.

Analysis on Collapsibility and Microstructure of Unsaturated Loess Using Fractal Geometry

This paper studies the microstructure of 16 group samples from three different sites of North-west region in P. R. China. Pictures of microstructure were processed with imaging processing program to acquire the geometer parameter and fractal dimension of pores. The range of pores’ fractal dimension is between 1.816~1.936. The pore distribution function of unsaturated soil is established based on fractal geometry theory. The pore water distribution of loess under natural moisture is analyzed. The relationships of collapsibility coefficient with fractal dimension and porosity of unsaturated pores are analyzed with the method of regression analysis. A larger fractal dimension represents a more complex pore-structure. The collapsibility coefficient of loess increases with the increase of fractal dimension and porosity of unsaturated pores.

Study on Reasonable Feature of Compaction Loess with Air Porosities

The degree of compaction is usually used as the compaction quality and control indicator of backfill in practical project. However, as the degree of compaction is affected by various internal and external factors, its accuracy is difficult to guarantee. In this paper, compacted loess samples were prepared under different compaction energies by normal compaction method. The curves of compression coefficient and dry density, the compression coefficient and porosity of compaction loess samples under different compaction energy are analyzed while the water content is constant. The air porosities of compaction loess samples under different compaction energy and water content are calculated and summed up. The air porosity of compaction loess samples under different compaction energy is more stable than the degree of compaction when the water content is exactly equal to the optimum water content. The rationality of using air porosity as the loess compaction quality control indicator is discussed. It is proposed using air porosity as additional indicator of compaction quality control on the condition of the loess compacted dry density meeting the requirements. The air porosity less than 6.5% is suggested as the additional quality control indictor for region backfill compaction.