Abstract:A new foundation treatment method is put forward in this thesis. The widened foundation was handled by the integrated application of rigid piles and vertical geotextile material. For investigating the performance of widened embankment under the embankment loads with the direct connection method on soft ground improved by application of rigid piles and vertical geotextile material, a 3D elastic—plastic finite difference model was established in FLAC3D. Through using numerical analysis, the settlement of widen embankment, lateral deformation and stability of the foundation were investigated from reinforcing or not. The results show that the comprehensive application of rigid piles and vertical geotextile material can effectively control the lateral deformation of foundation soil, thereby reducing the different settlement between the new and old embankment and surface, the reinforcement effect is obvious.

Abstract:In order to further study the water distribution of expansive soil slope protected by geo-membrane protection scheme during rainfall and evaporation, and verify the feasibility of geo-membrane protection scheme, laboratory model test for geo-membrane protection program is conducted. Make the expansive soil slope model go through the cycle of artificial rainfall and evaporation, in which volumetric water content probes are buried at different depths, so that the moisture content at different depths in the slope model can be measured at any time. The results show that the geo-membrane impede rainwater infiltrating into soil under the geo-membrane during wet and dry cycle, which make the soil under geo-membrane maintain a lower moisture content corresponding with a higher suction in the soil water characteristic curve. This will increase the effective stress of the soil and the stability of the slope. In this paper, to discuss the coverage of the geo-membrane at the back of the slope, the VADOSE/W module in the finite element software GeoStudio is used to simulate an expansive soil subjected to rainfall and evaporation cycle in the natural. By comparing the volume moisture content and suction in slopes of different coverage, it states that when the coverage of geo-membrane at the back of the slope is between 7 and 10 meters, soil under the geo-membrane at the edge of the slope won't be interfered with rainfall and evaporation and maintains a high suction state.

Abstract:A new type of stainless steel(Outer thin wall)-concrete-steel double walled hollow tube is presented in this paper. By using the basic assumption of the composite structural elements and the constitutive relation of the materials, this paper analyzed the bending bearing capacity of the normal section. Using the cross section method, the calculation formula of the bearing capacity of the bending members(DSTM)is established. Beside that, the finite element numerical method is used to analyze the results of the cross section method. The study show that the results of the two methods are basically consistent, and the formula can provide reference for engineering design.

Abstract:Uniaxial compression test is carried out using WAW-E2000 hydraulic servo universal testing machine under the four different air entraining agent content of concrete samples. We analyzed the compressive strength of concrete samples, elastic modulus variation, limit compression strain and damage property. The results showed that: With the incorporation of air entraining agent content increases, the compressive strength of concrete, elastic modulus and ultimate compressive strain decreased gradually, while the extent of the initial damage increases.

Abstract:Based on the actual monitoring data of a metro tunnel and Combined with the actual situation in the field of three-dimensional excavation simulation,we'd like to explore the variation of tunnel settlement and deformation in weak rock mass with the coupling of seepage stress. Through the simulation calculation and the actual circumstances of the results, to determine the supporting effect of combined supporting method in the surrounding rock breaking and groundwater seepage.So we can ensure the safety of tunnel excavation and save the excavation period to make an effective assessment.

Abstract:ABAQUS is used to simulate 6 different hollow specimens with different wall thickness and height, six stress components and three principal stress in a cylindrical coordinate system were summed up, and the end effect of stress distribution of properties were analyzed. Results showed that, the intermediate principal stress σ2 and radial stress σr within each of the height of about 10% at the ends, circumferential stress τzθ, axial stressσ1 and σ3 of about 20% at each end are under the influence of end effect. There are errors between real stresses of the sample end and middle, the decrease extent of σr and σθ are about 20%, 30%, respectively, and the errors of σz and τzθ are positively correlated with the thickness of the specimen. In order to reduce the effect of end-effects, the ratio of height to width is recommended to be 2.5, the ratio of inner to outer diameter is 0.8.

Abstract:Combining with some coal bunker project, two kinds of modeling methods are used through the software PLAXIS. The loading effect of coal is simplified as distributed load on the foundation in the former model while interaction of coal and foundation is emphasized in the latter one. Considering the result of splitting summation method, we can tell the difference of the two modeling methods in terms of ground settlement and structural response of pile foundation. It is found out that the settlement of foundation can be overestimated without consideration of coal-foundation interaction which is thought to be conservative in design. Moreover, as to the former model, the distribution of load transferred from coal also differs a lot from the one taking account of coal-foundation interaction, thus may causing misjudgment if pile capacity is not satisfied.

Abstract:There has been controversy on the calculation method of soil-water pressure in the design of the supporting structure. There are two methods to calculate soil-water pressure, soil-water pressure calculated separately and soil-water pressure calculated jointly. The theoretical mechanism of the former is very clear and definite, but pore pressure is difficult to measure. The latter can be suitably applied to some engineering, but the theoretical mechanism is not clear and definite. There is a special condition in retaining structures during operation period, temporary load is imposed on the surface of the soil. For the special condition, according to the CU strength envelope the method of determining the soil's state under the condition of undrained condition. It is based on the intrinsic connection between unconsolidated undrained triaxial tests and consolidated undrained triaxial tests. The principal stress and the excess pore pressure are calculated which are coursed by the increase of load, it is based on the CU strength envelope. A new approach is provided on the calculation of soil-water pressure for retaining structures under special conditions.

Abstract:Based on the Su'nan canal "four to three" channel upgrading project in Changzhou, and it's revetment structure composed of vertical steel sheet pile and anchor, the reasonable calculation parameters of soil has been obtained through inversion analysis. Based on the result of the inverse analysis, dynamic construction factors was considered. Also, three work progresses have been analyzed successively combined under practical engineering condition. Monitoring displacement of the piles was compared with the analyzed result to make sure the safety of each work progress. The results show that the simulation results are in good agreement with the measured values, which indicates that the inversion results are credible and can provide reference for similar projects.

Abstract:In this paper, through the experimental study on polyacrylonitrile fiber on mechanical properties of cement stabilized soil and the cement soil without side limit compression strength, splitting tensile strength, flexural strength, shear strength test and analysis were conducted. Results show that, fiber can obviously improve the cement soil of the mechanical properties of the matter. Fiber on cement soil splitting tensile and flexural strength increase is better than fiber on the compressive strength of cement soil improve. Fiber can greatly enhance the cohesion of cement soil, and under the same floating load shear strength.

Abstract:Small sub-domain filtering method is one of common methods in processing gravity data. After processing gravity anomaly data, the cascade bands of gravity anomaly become more convergent, which could be used to reflect geological boundaries. Multiple iterations can improve the effect of convergence, but they also cause serious distortions of boundaries of gravity anomalies. In order to remedy the defect, we use an improved small sub-domain filtering method which raises calculation speed and alleviates the distortions of abnormal boundaries by improving partition mode. We conducted a model experiment to verify the feasibility of this method. The Model experiment shows that geological boundaries can be better reflected by gravity anomaly data after reusing the improved small sub-domain filtering method several times, and the distortions of abnormal boundaries are well alleviated. We reused this method to process gravity anomaly data of Hulin Basin several times. Then we got the map of Hulin Basin faults distribution by the result, and a distribution of 25 faults was obtained. The result matches well with existing geological data.

Abstract:Based on the laboratory test, the destruction process of with or no suspended cut-off wall and different soil structure of 3 kinds of embankment piping were simulated, studied the mechanism of suspended cut-off wall control piping development and the impact of suspended cut-off wall on the development process of piping. The test results show that, set of the suspended cut-off wall in double layer and three layer embankment, the suspended cut-off wall can change the distribution of the osmotic pressure inside the gravel layer and the development path of piping failure, improve the hydraulic gradient of piping failure, can reduce the flux, the sand content and the extent of damage when the piping occurred. However, the piping failure forms of double and three layer embankment with the suspended cut-off wall are different, in double layer embankment, on the upstream side of the cut-off wall the piping failure was developed in the internal sand, but in three layer embankment, on the upstream side of the cut-off wall the piping failure was developed on the top surface of the sand layer.

Abstract:To examine the rationality of the existing overweight vehicle standards in China, American bridge limit load analysis method is used for China's typical vehicle calibration. First of all, on the basis of American bridge limit load formula, the basic form of systematic analysis of the bridge limit load formula and using method of typical vehicle. Secondly, this paper introduces the current Chinese standard overweight vehicles. Finally, this paper selects the study of highway bridge vehicle load standard of six kinds of typical vehicle, using American bridge method for calculating the limit load formula of China's typical vehicle for calibration.Results show that the overweight vehicles standards has many shortcomings, such as: standard overweight vehicles in our country is not standard, and determined on the basis of not clear of overweight vehicles, defining the standard is not unified; Typical vehicle axle load limits and car cargo gross weight limit is higher than by the bridge limit load calibration formula of axle load limits to cargo gross weight limit of the car. This paper suggest consider overrun vehicle standards adopted by the Chinese wheelbase parameters of vehicle load limit.

Abstract:As a new structural type, the integrated house with steel mortise-tenon connection has his characteristic technical superiority such as economical cost, simple design, modular production and construction. Involving complex structure stress and many difficulties in analyzing by traditional theories and FEM software, it is hard to define and assess seismic capacity of the buildings. So this paper consigned by a company in Suzhou studied the seismic behavior of integrated buildings by structural models with full scale on shaking table. Through simulated earthquake test on a shaking table, this paper analyzed the experiment data and phenomenon. The results proves that this type of composite joint had high strength and rigidity,and the house can resist 9-magnitude earthquakes and is well suited to be deployed in earthquake stricken zones.

Abstract:The status of air pollution in Handan city was based on the online observation data of atmospheric particulate matters and gaseous pollutants at four air quality monitoring stations during 2013 and 2014, as well as the meteorological observation data. It is found that the fine particulate matters were the key air pollutant in Handan. The annual average PM_2.5 concentrations in 2013 and 2014 were respectively 139 μg/m³ and 116 μg/m³, which were about 4 and 3 times of the national grade II standard (35 μg/m³). Comparing with 2013, the PM_2.5 concentrations in 2014 was reduced by 16.5%. In addition, the ratio of the days exceeding the standard dropped to 66.6% in 2014 from 74.4% in 2013. There was no obvious difference in the spacial distribution of PM_2.5 concentration in Handan. The PM_2.5 concentration was highest in winter, followed by autumn, spring and summer, while the PM₁₀ concentrations were in the order of winter> spring> autumn> summer. There were no clear differences in the concentration of PM_2.5 and PM₁₀ in a week, indicating that weekly changes are not obvious in the pollutant emissions and the relatively stable pollutant emission sectors, e.g., industries, played a key role. Correlation analysis between the meteorological condition and the pollutant concentrations indicated that the calm wind had the highest frequency in four seasons in Handan, and the wind direction was concentrated in the direction zone from the east to the south and to the west. Henan, Shandong and Shanxi contributed more to particulate matters of Handan.

Abstract:This paper establishes a model of R404a/CO₂ cascade refrigeration system with heat regenerator under the low-temperature environment. In order to improve coefficient of performance, a thermodynamic analysis are carried out. Through theoretical calculation,the influences of evaporation temperature, condensation temperature of low temperature cycle,the degree of supercooling as well as the temperature difference in the condenser evaporator on COP are contrasted and analyzed by control variable. The result showed that the degree of supercooling has obvious effect in improving COP when the other parameters are constant ;there exists a optimal value of condensation temperature of low temperature cycle makes COP to be maximum; COP increases with the increase of evaporation temperature and the temperature difference in the condenser evaporator while decreases with the increase of condensation temperature when the degree of supercooling is constant.

Abstract:Taking Qujiang Gao Keng subinclined belt shaft head chamber as the engineering background, it's floor heave characteristics and mechanism and it's floor stress distribution were analyzed by theoretical analysis, numerical simulation, field test method. The main reason of floor heave and asymmetric deformation was frequent disturbed, unbalanced stress distribution and rock properties etc. To control the stability of surrounding rock of the chamber, the key measures is to control the uniform stress distribution, followed by controlling the shallow rock stress concentration degree, and finally improving the roadway surrounding rock. The surrounding rock deformation can be controlled. According to the principle of floor heave steps control,"the first step is to borehole pressure relief, the second step is to cable + channel + spray" is proposed and is put into effect in that tunnel. The new supporting scheme chamber plastic zone and stress change with original supporting scheme were compared by utilizing numerical simulation.Engineering practice shows that the new supporting scheme effect is good for controlling the relative displacement of head ends and the floor heave, the key measures is to control the uniform stress distribution

Abstract:In order to find out the gas source of gas hydrate in Muli coal field, Qilian Mountain permafrost, geochemical characteristics of Triassic source rocks are studied. According to the depth, 36Triassic samples of JN well were collected. First, for analysis of the maturity and hydrocarbon potential, the normal geochemical experiments, for example, rock pyrolysis and analysis of organic carbon were completed. Then 9 samples were selected to carry out the microscopical maceral identification of organic petrology test. Finally, 4 samples were studied by Soxhlet extraction and GC-MS test. The results showed that research region Triassic source rocks mostly are in high maturity stage; Organic matters mainly belong to Ⅱ-Ⅲ type, which are mainly from higher plants and lower aquatic organisms mixed sources; the sedimentary environment is the epicontinental sea and shore-delta; Organic matter abundance is in relatively high, belonging to mid-good source rocks.

Abstract:The Yeniu gully in Wenchuan country outbreaked a debris flow on July 3,2011.It blocked the 2/3 of channel Minjiang River, causing huge economic losses.This paper analyzed the formation conditions, disaster characteristic and the formation mechanism according to the field investigation.This paper also studied the possibility of blocking the river and the trend of development. The results show that the Yeniu gully changed into a debris flow after the 5.12 Wenchuan earthquake.The characteristics of it are persistence, paroxysm and group occurrence. The initiated process can be summarized "fire-pipe effect". The overland flow of water concentrated into steep channels runoff and sources from gully-bed loose deposits. The forming process can be divided into three stages: shock starting phase, acceleration crevasse phase and accumulation phase. It can cause river blocking when the debris flow is excited by P=1% and above.

Abstract:The biological reef reservoir as a kind of good oil and gas are concerned by more and more people. The forming conditions of reef were mainly controlled by reef-forming organisms, the effective sediment rate of particle, early cementation, palaeostructure, rise and fall of sea level, temperature, analyzed the reef conditions on a specific role of the characteristics of the reef, and the sea level rise plays a main role on the reef process. From a biological perspective, this paper proposes a new classification method of the reef, namely according to the growth rate of the feature of reef-forming organisms, which divided into adjustment period, growth period, stable period, decline phase, and analyzed the process of the reef in detail. The relationship between the biological reef and oil and gas was discussed and it is suggested that the barrier reef on the edge of the platform is the key object in the exploration of oil and gas.

Abstract:For discussing the characteristics and sources of the hydrothermal fluid in the gold mineralization zone in Hongshan complexes near Handan city, homogenization temperatures and salinities of the fluid inclusions in quartz vein from this area are tested, trace elements and Rb-Sr isotopes of the quartz vein are analyzed; the temperature and pressure, pH and Eh values of the fluid inclusions being taken are estimated. The results show that, fluid inclusions are mostly liquid and liquid-rich types with the homogenization temperatures varying from 206℃ to 305℃ and a mean of 254℃, and with the salinites varying from 7.17 wt%NaCl to 10.19 wt%NaCl and a mean of 8.36 wt%NaCl, they belong to the low-temperature and low-salinity hydrothermal fluid. Those inclusions are taken at a mean temperature of 303℃ and a mean pressure of 721×10⁵Pa or a depth about 2.40km. The fluid enriches multiple trace elements and their contents are influenced by the temperature and pressure and so on, the Rb-Sr isotope ratios are higher than the main intrusive rocks, wall rock or ones around the complex area. These characteristics reveal that the hydrothermal fluid is obviously characterized by the meteoric water.

Abstract:In order to improve the stability and safety of converter, the problem existing in conventional feedback circuit is analyzed and settled, and the design of security protection performance of current limit, over voltage and temperature has been added in main circuit. The experiment proves that the output voltage of conveter with improved feedback circuit is more stable and the output voltage ripple is smaller.

Abstract:A physical model of circle tube with Circumferentially Non-uniform Heated, of which the inner diameter was 16mm and wall thickness was 2mm, was built to numerically investigate the heat transfer of molten salt in the circle tube. The numerical investigation was performed within the range of inlet temperature from 200 to 400 ℃, velocity from 0.6 to 3.0 m/s, heat fluxes from 200 to 400 kW/m². By using the k-ε model, the temperature distribution at outlet section and transfer characteristics were analyzed in detail, as well as the distribution of inner wall temperature. The investigation results show that the temperature of tube wall has large difference at outlet section, and the temperature of molten salt also has a graded distribution. The lower the inlet temperature is, the better the transfer performs. The heat flux has little effect on Nusselt Number. The temperatures at inner wall are non-uniformity on the circumference, increased inlet velocity and decreased heat flux are beneficial to improve the circumferentially non uniform.