Abstract:This paper described the equipment and test methods of the two dimensional soil arching laboratory tests. The distribution of vertical stress in the embankment was reported, and compared with the results of Terzaghi and Hewlett & Randolph methods. The modification of the Hewlett & Randolph method was also discussed. It was found that the ratio of embankment height h and pile spacing s play an important role in the formation of soil arching. The laboratory test results show that there is no soil arching for h/s <0.67, partial soil arching generated for 0.67< h/s <1.33 and fully soil arching generated for h/s ≥1.33. The distribution of vertical stress in the embankment captures the same tend of the results of Hewlett & Randolph method for h/s ≥1.33. The difference between the results of modified Hewlett & Randolph method and experimental results is smaller than that of Hewlett & Randolph method. The effect of embankment height on the stress ratio between piles and subsoil n were also investigated, it was found that the value of n increases with increasing the embankment height, whereas the growth rate reduced with the increase of embankment height.

Abstract:A series of artificial silt with different sand ratios (10%,20%, 40%) is prepared, with the improvement tests, the improvement effect of different modifiers(lime and sodium silicate, lime and fly ash) with different proportion on silt has been investigated. the results show that with the increase of sand rate, either soil or modified soil, the maximum dry density increases; contrary to the lime and fly ash modified soil, the maximum dry density of lime and sodium silicate modified soil is significantly reduced; the optimum moisture content of lime and sodium silicate modified soil and soil is slightly different, however, for lime, fly ash modified soil and soil, the optimum moisture content is basically the same; with the same sand ratio, the maximum degree of compaction and the optimum moisture content of the lime and sodium silicate modified soil with different ratios have not changed greatly, the compaction ratio of 10% lime and 20% fly ash is higher than the others; at a constant degree (95%) of compaction, the unconfined compressive strength of modified soil is significantly higher than silt, and plays a "stable" effect, the modified additive quantity is the key factor of the unconfined compressive strength.

Abstract:The lateral inertial effect of the pile is considered on the basis of one-dimensional bar, coupling vibration equation of large diameter pile and three-dimensional continuum soil is established, and the semi-analytical solution of time response of large diameter pile is obtained. The dynamic effects of the parameters of the large diameter pile on the pile-soil system are analyzed. Then, the large-diameter model piles are tested in laboratory, and the small-strain exciting force is applied to the top of the model piles. The pile top data are collected by the EPPDS wireless piles dynamometer. The correlation parameter are analyzed by changing the diameter of the model pile and the pile body material. The results of theoretical calculations are compared with the experimental data to verify the correctness of analytical solution and the reliability of practical guidance.

Abstract:Based on the Rapid-Transit Tram Project in Nanjing, three soft soil improvement methods including replacement method, vacuum preloading method, as well as vacuum preloading combined with cement-soil mixing pile method were introduced in this paper.. The reinforcement method and the construction technology were reported in detail for the three methods. The post-construction settlement of the soft soil foundation reinforced by the three methods was investigated. It can be found that the post-construction settlements were 15.8 mm, 13.2 mm and 8.6 mm for replacement method, vacuum preloading method, and vacuum preloading combined with cement-soil mixing pile method respectively, which were much less than the cumulative alarm value of 100 mm. It can be concluded that these three improvement methods reinforced the soft soil foundation effectively, whereas the reinforcement effect of the vacuum preloading combined with cement-soil mixing pile method is better than the other two methods.

Abstract:Based on the field measured data from three projects in different industries, by the use of several types of commonly used settlement prediction model and the new prediction method proposed in recent years, this paper proposes the Extended Langmuir Model of settlement prediction with a widely applicability. Through the comparative analysis and validation, the model has the advantages of higher accuracy, reliability and applicability, so that, it can be widely used.

Abstract:The swelling properties of remodeled swelling rock were carried out in the test section project of leading water from Yangtze to Huaihe River. By the test of free swelling ratio, swelling ratio under different pressure and saturated direct shear test, the properties of swelling ratio under different initial water content and different pressure were explored; the relationship between expansion ratio with initial expansion rate was analyzed. The conclusion show that initial expansion rate is quadratic positive correlated with expansion ratio, the strength parameters are negative correlated with expansion ratio.

Abstract:The mesostructure of soft soil has important influence on the consolidation process，it is of great guiding significance to consider soft soil structure from meso level and reveal the law of consolidation in a large area of reclamation project. In this paper, we establish the soil mesoscale model based on the discrete element method, match mesoscale parameters of the model according to the laboratory test, analyze the distribution of the seepage field in the soil body with COMSOL, realize to solve the consolidation problem of soft soil with PFC-COMSOL, and compare the analysis scheme with the laboratory test. Research results show that simulating flocculation soft soil with poly grain can truly react mesostructure characteristics of soft soil; Creep can influence the decrement in the process of consolidation of soft soil, creep should be considered in calculating the amount of soft soil compression; Uneven compression appears firstly in the process of consolidation of soft soil, after the excess pore pressure is dissipated completely, the soil recovers uniformity.

Abstract:Based on Hang-Ping-Sheng line waterway upgrading project in Pinghu City, considering effect of old revetment, the simulating the dredging experiment of sheet pile revetment with different cantilever length of sheet pile is implemented by the finite element software, then the comparative analysis is conducted for the horizontal displacement, internal stress and stability of revetment of sheet pile revetment with different cantilever length of sheet pile. In addition, the study of influence rule of cantilever length on sheet pile revetment is extended under the condition of different embedded depth. The results show that cantilever length of sheet pilehas obvious influence on deformation and trend of failure of revetment in the overlapping region of sheet pile and old revetment, but it has a very little influence on internal stress of sheet pile. In the overlapping region, the decreasing of cantilever length of sheet pile is conducive to stability of revetment, but when the top of sheet pile is lower than the bottom of old revetment, with the decreasing of cantilever length of sheet pile, the global stability safety factor FOS begins to decrease gradually, and with the increasing of embedded depth, the effect of cantilever length on stability of revetment becomes weaker.

Abstract:With laboratory testing rig and testing program designed, the fine sand, medium sand and coarse sand are chosen as test material respectively, and the salt solution is chosen as tracer agent, then the seepage velocity is calculated through the relationship between the conductivity of tracer agent in different test material and time. The value of seepage velocity calculated through traditional dilution formula in all sand layers is a little larger than that by testing discharge method. The specific value of them is constant in the same hydraulic gradient, while it is imparity in different sand layers. The dilute tracer correction coefficient is proposed as well as the modified dilution formula, meanwhile the experimental value of dilute tracer correction coefficient is given.

Abstract:For those bridge piers built in water, almost all faced with the problem of pier scour. Based on the analysis of water depth sensor and axial force sensor test data of the No.4 main pile of Sutong Bridge in the Yangtze Rive downstream, we found that the scour protection scheme used on the bridge not only prevented the pier scour, and many protective sand bags had been squeezed into the soft riverbed material layer within a certain depth when the steel tube was inserted, which greatly enhanced the ultimate friction resistance of loose bed surface, improved the bearing capacity of pile foundation. The practice proved that the scour protection scheme is scientific and effective, and has important reference value for the design of construction engineering.

Abstract:The traditional linear elastic model cannot simulate the nonlinear seismic response analysis of RCC gravity dam in strong seismic regions．This paper analyzes? the seismic damage characteristics of Ludila RCC dam, when dam and foundation material nonlinearity? are considered at the same time. The main conclusions are as follows: When the foundation rock mass and the dam use the nonlinear materials, the foundation near dam toe is damaged, and with the continuous ground motion, the damage cracks extend gradually to the depth of the foundation. Thus, the stress redistribution of dam body and the stress concentration release at the juncture of dam foundation, which will not cause the earthquake damage at the dam foundation junction. Therefore the earthquake damage area and damage degree of the dam are reduced, which makes the dam more partial safety. The result will be more close to the actual, which has certain reference significance to the guiding project.

Abstract:The cost control model can show the change trend of the cost in the construction stage, control costs reasonably, and reduce the cost of construction risk. Based on the advanced BIM5D technology and the earned value method, this paper explores the potential advantages of BIM5D technology deeply in cost control, and analyzes the system implementation process of the cost control model systematically. The feasibility of the construction cost control model based on BIM5D technology is demonstrated through the cost control process of a certain Information Building in Beijing.

Abstract:Based on the thermal response tests of 3-day and 2-day in a test well in Xingtai, the effects of heating power, testing time and initial soil temperature on the thermophysical parameters of rock and soil were studied. The results show that under the same test area, different heating powers have different results. The measured thermophysical parameters of rock and soil are relatively stable when test time vary from 48 to 64 hours. The higher the initial soil temperature is, the smaller thermal diffusion coefficient of rock and soil is.

Abstract:In order to analyze the motion characteristic of clay landslide, the circular sliding surface is defined as the most dangerous slip plane according to clay landslide characteristic. Base on the assumption that landslide moves as a group of particles motion, the physical motion model of landslide failure is established. Base on function transformation relations, in the process of landslide movement the forecast formula of landslide distance is deduced. Kinetic parameters such as motion acceleration velocity, sliding distance are obtained by calculation. Compared with the sled model, this method can be used for landslide case. The case results show that the motion acceleration of homogeneous clay landslide approaches to its maximum immediately in a very short time, and then reduces gradually. Landslide movement speed increases rapidly in the initial stage, then slows down gradually until the landslide movement stops. The final horizontal sliding distance of this method is equal to the result calculated by the sled model approximately, and the relative error is only 1.2%, which is very small.

Abstract:Ordos Basin is an important oil and gas exploration and development area in china, Oil and gas structures are formed by compaction in multiple horizons. By the influence of the ancient landform, the differential compaction structure and other structures combine to form various types of oil and gas reservoirs, which are rich in oil and gas resources. Based on the detailed analysis of sedimentary and hydrocarbon accumulation characteristics in Ordos basin, the process of differential compaction in this region can be divided into three stages: compaction and drainage, compaction and hydrocarbon expulsion and elastic compaction; The effect of differential compaction is not only affected by the type and content of sand and mud, but also by the paleogomorphology; Different types of favorable traps can be formed by the combination of differential compaction and lithology, regional structure and paleogeomorphology. The understanding of differential compaction and favorable trap types is beneficial to the deep exploration of oil and gas resources and the rational development of oil and gas reservoirs.

Abstract:A series of nature rubber (NR) composites with modified kaolinite was prepared by melt bending. The effect of kaolin content on the flame retardancy and thermal stability of NR composites was investigated. The flame retardancy and thermal stability are obviously improved compared with the pure NR. The thermal stability of MK/NR is equivalent to CB/NR and better than PS/NR, and the flame retardancy of MK/NR equivalent to PS/NR and inferior to CB/NR when NR is filled with 50 fraction MK, PS and CB respectively. In the nature rubber matrix when it is filled by kaolin of 70 phr, the mature house-of-cards structure is edmanifest.

Abstract:The main factors affecting the purity of aphanitic graphite are discussed. This artcle pointed out that quartz, kaolinite, illite, andalusite, sericite and a small amount of impurities such as pyrite, tourmaline, limonite and calcite, are the main factors influencing the purity of aphanitic graphite. This paper introduces the methods of physical purification and chemical purification, which are used in the purification of graphite. The principle, technical features and existing problems of various purification methods above are analyzed. The development of the technology for the purification of the crystalline graphite is prospected. It is pointed out that the purification technology of the crystalline graphite will be in the direction of energy saving, environmental protection and synthesis.

Abstract:Based on the feasibility study of the national road network, this paper obtain the one-hour traffic circle of New City/District. Based on the national hospital data obtained by using the internet to develop data, the 551 National New Cities/Districts are conducted a comprehensive evaluation of medical security through the opportunity accumulation model, and ultimately the results of quantitative are sorted. The results show that: ① In the area of traffic, the new urban area with large reachability is concentrated in the eastern coastal areas, and the western region is relatively small. ② For the medical security services, China's new district medical security insurance services distribution is relatively uneven, the top 50 new cities/districts gathered in the Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta, the three major urban agglomeration. The top five provincial administrative districts are Beijing, Shanghai, Chongqing, Tianjin, Shaanxi Province. Safeguard services of new city/district in Xinjiang province are relatively weak.

Abstract:Based on the mechanism of PM_2.5 concentration change in Beijing in 2015, the generalized additive model (GMA) of PM_2.5 and atmospheric pollutants (PM₁₀, SO₂,NO₂,CO,O₃), as well as the meteorological factors (daily mean temperature, wind scale, wind direction) are established to explore the impact of different factors on PM_2.5 concentration changes. The results showe that: (1) Beijing PM_2.5 concentration has the characteristics of low distribution of summer and autumn, however higher in spring and winter; (2) The PM_2.5 concentration in Beijing is linearly positively correlated with PM₁₀, SO₂, NO₂, CO. The positive correlation is from strong to weak: CO> PM₁₀> SO₂> NO₂, and the relationship with O₃, temperature and wind factor is more complicated. (3) The goodness R² of the GAM model is 0.725, and the goodness of the linear regression model is 0.519. Compared with the GAM model, the explanatory degree of the PM_2.5 concentration increased by 20.6%. The results show that the GAM model is more flexible and reliable than the linear regression model in establishing the complex relationship between PM_2.5 concentration and influencing factors.

Abstract:In order to monitor and analyze wheat straw burning of Beijing-Tianjin-Hebei Metropolitan Region during or after the wheat harvest, and provide the government abundant decision-making assistant information to forbid wheat straw burning, based on the fire products (MOD14/MYD14) and land cover products (MCD12Q1) of MODIS, the wheat straw burning points were extracted during the June of 2005-2015, and the patterns of spatiotemporal variation of wheat straw burning points were also investigated. The results showed that the wheat straw burning of the study area in June mainly concentrated in Handan, Xingtai and Hengshui were the most serious. The number of wheat straw burning points first decreased and then increased, and the wheat straw burning points showed a change trend from southeast to the northwest over time. Time series analysis indicated that number of wheat straw burning points had a general increase trend except hosted the Olympic Games (2008) during 2005-2015; the time of occurrence concentrated in mid-June, and the statistical figure of the whole June was similar to the normal distribution.

Abstract:In order to strengthen the regional haze control, taking Handan city as an example, the gray relational model is used to analyze the causes of fog and haze comprehensively. The conclusion suggests that haze is derived from industrial pollution, vehicle exhaust emissions and the city's main domestic pollution emissions and so on. Then we analysis and evaluate existing haze prevention and control measures by statistical methods. Finally, we provide a reasonable proposal of governing regional haze.

Abstract:This paper is to solve the problem that the large number of full face tunnel boring machine (TBM) can not be used in the whole life, as well as the related problems of damage repair. By reviewing the literature at home and abroad, we analyze the influence of TBM cutter wear, fatigue, creep, fracture and other factors, the micro crack propagation mechanism of cutter. The multiple damage model under TBM specific service environment (operating parameters of geological parameters, structure parameters, etc.) is built. In this paper, the multiple damage coupling framework is put forward from the aspect of remanufacturing cutter head.