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This paper presents the analyses of toppling response of layered reverse-dip slopes under the influence of geometric factors of slope angle, strata thickness and dip. The toppling response of reverse-dip slopes under different geometric factors is obtained by using the discrete element code UDEC. Then, a prediction model for toppling deformation is developed by utilizing support vector machine and the toppling-prone combinations of these geometric factors are determined from a total of 120 samples of reverse-dip slopes. The study has shown that the geometric model is a quarter of a spheroid with a slope angle of 80°, a strata dip of 80°, and a strata thickness of 0.19 m as the center. The length of the long equatorial radius of the spheroid is 31° (strata dip axial), that of the short equatorial radius is 21° (slope angle axial), and the polar radius is 0.075 m (strata thickness axial). And the ratio of long equatorial radius, short equatorial radius, and polar radius is 2.48:1.68:1.00.

The movement of the ground caused by the excavation of subway tunnels and the sinking of the earth's surface inevitably affect above-ground buildings, with the impact on historical and cultural buildings, which are already in disrepair, being more prominent. In existing research, the impact of the stiffness of a building itself is often neglected when assessing the influence of the displacement of the stratum caused by tunnel excavation on the building. However, as the settlement and deformation of the building are related to the structural characteristics of the building itself, the effect of the building stiffness should not be completely ignored. This study analyzed the case of the national key protected cultural relics (Red House Hotel) located near the tunnel of the Qingdao Metro (Line 3). Based on the factors affecting the stiffness of the building structure, the Peck empirical formula was modified to predict the effect on the building in the stratum. Subsequently, a three-dimensional finite element model was established and force analysis conducted. Considering the results of the finite element analysis, which determined the stress condition of the cultural relic buildings, a reinforcement design was carried out and implemented in the project.

The determination of slope failure areas plays an important role in slope stability problem. The previous studies evaluate the failure area either based on the slip surface with minimum factor of s...

As a type of carbonate reservoir and main oil-gas production formation in the Tarim Basin, China, fractures and paleokarst caves in Ordovician limestone are the targets of interest for seismic exploration in the S48 well area. Although conventional 3D, high-density, and wide-azimuth seismic acquisition has been widely applied in the Tarim Basin, we still need to determine what 3D 3C seismic data can further do for the characterization and fluid detection of the carbonate reservoir. In the S48 well area of the Tahe oilfield, we had acquired 3D 3C seismic data with single digital 3C sensors at the same grid, whereas the traditional 1C acquisition had arrayed geophones. Through comparison and analysis of two kinds of seismic data, including field records and migration profiles, some important characteristics can be found: (1) The [Formula: see text]

To better understand the mechanism of development of lateral resistance of single drilled piles installed in improved soil profile. Side-by-side static load tests were performed on the piles installed in virgin soil profile and improved soil profile with the soil ahead of the pile cement-improved. Parametric three-dimensional finite element analyses were performed to study the effect of grouting radius. More soils at the side of piles make a critical contribution to resisting lateral loads due to the influence of improved soil ahead of the pile. A new hyperbolic p–y function that modifies the initial subgrade modulus and the ultimate lateral soil resistance is proposed based on the finite element analyses to account for the effect of the cement improvement. The proposed p–y method is capable of predicting laterally loaded pile response in cement-improved soil profiles as measured in the static load tests. The accuracy of the proposed p–y model is appropriate as shown by comparing measured and calculated the lateral behaviour of the single pile.

During the construction of subway tunnels in permafrost areas, there are more factors of permafrost deformation in the deformation of rock stratum and ground settlement above the tunnels. Due to the frost heave effect of soil freezing in winter and the thawing phenomenon of frozen soil during thawing and thawing in spring, the ground settlement will occur, so the law of ground settlement caused by subway tunnels and its impact on ground construction facilities are more complex. The characteristics of surface heave caused by frost heave in winter and thawing caused by thawing in spring are studied. The evaluation method of ground thawing caused by subway tunnel construction in permafrost area is given. The ground settlement during tunnel construction in seasonal permafrost area is studied through specific engineering examples. The research shows that the ground settlement caused by tunnel excavation in this case area accounts for 53% of the total ground settlement, the ground settlement caused by frost heave accounts for 27% of the total ground settlement, the ground settlement caused by thawing and thawing of tunnel frozen soil accounts for 20% of the total ground settlement. The research results can provide reference for the understanding of ground settlement caused by tunnel construction in permafrost areas and its disaster protection.

Planetary system trajectory is inherently related to sun movement. Considering that planetary system movement affects solar activity and even global climate change, studies on its changing law and characteristic are of significance and values. In this study, the kinematic index of planet heliocentric longitude is created based on the orbital elements of planets in the solar system. Both the planet juncture index and heliocentric longitude are used to investigate the periodic planetary system movement around the barycentre of the solar system. The planet juncture index is the norm of the total quality-vector-weights for planetary system. It represents the distance between the barycentre of the planetary system and the sun. When all planets nearly align, the planet juncture index peaks; otherwise, it falls. The planet heliocentric longitude is the angle between the line from the projection of the barycentre of the planetary system onto the datum to that of the sun and the datum axis. The planet heliocentric longitude ranges from 0 to 2 π . The planet juncture index and heliocentric longitude are two important kinematic indexes for researching the changing law and characteristic of planetary system movement. The former represents the distance between the barycentre of the planetary system and the sun and the degree of convergence and separation of the planetary system. The latter represents the exact location of the barycentre of the planetary system relative to that of the solar system. This study explores the changing rule and characteristic of planetary system movement through the two kinematic indexes. Results of this study bear significance and value on theories of studies on solar movement, solar activity and global climate change. The power spectrum analysis method is a spectral analysis indicating digital time-series in different frequencies of energy distribution, which reflects the distribution of power spectrum in different frequencies of stochastic signal. The implied periodic trends in the frequency domain are revealed with the power spectrum analysis method by analysing the character of signal and processing every coordinate time-series with Fourier transform. Both the planet heliocentric longitude and juncture index are studied through numerical simulation. The base data of the variations of planet juncture index and heliocentric longitude for nearly 2000 years are derived. The comparison between the base data of the two kinematic indexes show that both exhibit periodic trends and varying characteristics similar to those of the planetary system movement. The power spectra of results reveal that both the planet juncture index and heliocentric longitude are complicated, with remarkable periodicity parameters of 35.958, 19.873, 13.768 and 12.807 a for the former and 162.602, 29.446, 11.865, 8.457, 7.421 and 5.936 a for the latter. The most remarkable periodicity parameters are 19.873 and 11.865 a. To a certain extent, these periodic trends provide basis for analysing solar activity and global climate change. Planet juncture index indicates the moving pattern of the barycentre of the planetary system around that of the solar system and thus specify the moving pattern of the sun around the barycentre of the solar system. Planet heliocentric longitude indicates the accurate position of the barycentre of the planetary system relative to that of the sun and thus indicates the accurate position of the barycentre of the solar system relative to that of the sun. Both provide an effective means to investigate the relationship between sun movement and solar activity.

In this paper, the relationship between the dynamic surface subsidence and overburden separated strata has been studied under the condition of sedimentary coal measure strata. When the underground coal seam is mined, the ground surface subsidence will be caused. The surface subsidence is caused by the goaf clearance passing along the overlying strata up to the surface. During the course, the bed-separation space would be generated and its size directly affected the value of mining goaf passing up to the ground - the surface subsidence. It shows that the surface subsidence is closely related with overburden separated strata. Therefore, the research on the dynamic development law of overburden separated strata contributes to recognition and prediction of surface dynamic subsidence, which is the important basis for the control of mining subsidence damage. In this paper, the whole processes form cracking, propagation, to closure of the mining overburden separated strata are analyzed in the first chapter. The various steps of surface dynamic subsidence, from the initial step, the active step, and then to the recession are researched. And then the corresponding relationship between the surface dynamic subsidence and overburden separated strata is studied and its model is established for analyzing factors of geological and mining that influenced this relationship. At last, a similar material model for coal measure strata in sandy shale is established and carried on the excavation experiment of coal seam. Then by use of the test, the development law of mining overburden separated strata is studied, and the space-time corresponding rule of the surface subsidence and overburden separated strata is analyzed. And on this basis, we find the relationship between the surface subsidence and overburden separated strata. Based on allometric growth of mining overburden separated strata, which would provide a new research and analysis method for control and prevention of mining subsidence damage, we establish the model of mining subsidence.

In this paper, a comprehensive analysis of spatiotemporal characteristics of reverse-dip slope toppling is conducted by taking the Xiaodongcao slope as an example. First, a spatial partitioning analysis of toppling deformation is performed based on the field reconnaissance and interpretation of engineering geological data. Then, the variations of toppling deformation in time domain are analyzed for different areas of the slope with monitored data of surface displacement. Finally, the isochrones of toppling displacement evolution are constructed by using inverse distance weighted interpolation of surface monitoring data at discrete locations. The results presented in the study have shown that: (1) the displacement at the rear of the slope is dominated by vertical deformation, whereas the horizontal deformation is predominant at the slope front which also controls the overall deformation of the bank slope; (2) the overall evolution of slope deformation is dominated by the strip area at the center of the slope. In particular, the overall deformation of the slope lags behind the central region, and the displacement in this strip area could trigger an overall displacement of the bank slope. It is thus inferred that the stripe area serves as the locked segment for the toppling deformation of the slope.

To investigate the effect of creep characteristics of soft soils on time-dependent deformation of root-caisson foundation, long-term lateral loading tests were performed about 120 days in Wangdong Yangzi River Highway Bridge. The displacement of caisson head, the deformation of the caisson along depth and displacement field of soil ahead the foundation were measured under the constant load. Comparing the short-term deformation and long-term displacement of root-caisson, soil creep effect and time-dependent displacement of foundation are revealed. The results show that deformation of this root-caisson presents characteristic of the flexible foundation. From the entire process the lateral displacement of caisson vs time curve, the horizontal displacement at the top of caisson increases gradually with the continuous time of the constant load, the displacement rising rate declines gradually, and the horizontal displacement finally tends to a stable value. The deformation of the caisson in the holding load stage is larger than the one in the loading stage, the final horizontal displacement of the caisson top is 2–3 times the instantaneous displacement. The rebound displacements of the caisson are small with experiencing a long-term horizontal load after unloading, the creep deformation of the soil occurs under long-term horizontal load.

Laterally loaded piles may entail large deformation under some circumstances such as ship impact, earthquake and long-term horizontal thrust of arch bridges, etc. The arch bridges are especially sensitive to horizontal displacement of foundation. Lateral load test was performed on a full-scale pile in virgin soil and pile with post-grouted soil around pile. Further numerical simulation analysis was carried out by PLAXIS3D based on field test result. The analytical and measured results are found to be in fairly satisfactory agreement. According to test results of single pile, lateral response of piles largely depends on profile of limiting force in shallow soil. Horizontal bearing capacity of bored piles is improved via grouting technique. For pile with post-grouted soil around, horizontal displacement of pile top is significantly reduced. The maximum bending moments of pile with grouting decrease dramatically. The grouted upper soil expands range of effective soil around pile, and more horizontal thrust was shared.

Laterally loaded piles may entail large deformation under some circumstances such as ship impact, earthquake and long-term horizontal thrust of arch bridges, etc. The arch bridges are especially sensitive to horizontal displacement of foundation. Lateral load test was performed on a full scale pile in virgin soil and pile with post-grouted soil around pile. Further numerical simulation analysis was carried out by PLAXIS3D based on field test result. The analytical and measured results are found to be in fairly satisfactory agreement. According to test results of single pile, lateral response of piles largely depends on profile of limiting force in shallow soil. Horizontal bearing capacity of bored piles is improved via grouting technique. For pile with post-grouted soil around, horizontal displacement of pile top is significantly reduced. The maximum bending moments of pile with grouting decreases dramatically. The grouted upper soil expands range of effective soil around pile, more horizontal thrust was shared.

In June 2006, samples were collected from a 90 cm snow-pit at an elevation of 5 040 m a.s.l. in the northern branch firn basin of the Glacier No. 12, Laohugou Valley, in the western part of Qilian Mountain, China. Oxygen isotopes (δ 18 O) and major soluble ions were measured. Results showed that Ca 2+ is the dominant cation, and SO4 2- is the dominant anion. All major ions have close positive correlations with eachother except NO3 - and NH4 + . δ 18 O show positive correlation with air temperature. The method of correlation analysis, sea-salt ion tracer and trend analysis were used to determine the source of the chemical components. The correlation analysis and HYSPLIT backward trajectory analysis suggest that atmospheric soluble dust species dominate the chemical signature.

Stable lead (Pb) isotopic fingerprints provide opportunities to trace natural and anthropogenic Pb sources in the environment. In order to evaluate Pb deposition from different sources over mountainous areas of western China, Pb isotopic compositions were characterized from modern aeolian dust in 15 snowpit samples collected from 13 typical mountain glaciers between 2008 and 2010. Most of the snowpits sampled cover more than a whole year of accumulation and overlap with each other on deposition date. Pb isotopic variability among all the samples is small, varying in the range of 18.1399-18.9199 for Pb-206/Pb-204, 15.5979-15.8743 for Pb-207/Pb-204, 38.2272-39.9453 for Pb-208/Pb-204, 1.1605-1.2009 for Pb-206/Pb-207 and 2.4433-2.5182 for Pb-208/Pb-207. Three isotopic plots of the different Pb isotope ratios (Pb-207/Pb-204 vs. Pb-206/Pb-204, Pb-208/Pb-204 vs. Pb-206/Pb-204, and Pb-208/Pb-207 vs. Pb-206/Pb-207) in all the samples show identical geographic trends, with more radiogenic in the south and less in the north. This trend is consistent with the distribution of natural dust sources and supports the interpretation of a regional/local source for insoluble particles (IP) to snow/glaciers in this region. Comparison with the Pb isotope results from potential dust sources, however, it shows that the Pb isotopic compositions of IP samples in snow samples are relatively less radiogenic. Parts of these less-radiogenic Pb isotopes are comparable with the ice core results during recent decades, which are shown to be influenced by anthropogenic sources. At sites located along the periphery of western China, the Pb isotopic compositions are much closer to anthropogenic results. Natural and anthropogenic Pb sources are roughly assessed using a simple binary model. The sites with a high anthropogenic fraction are at lower elevations and are relatively close to population centers. (C) 2013 Elsevier Ltd. All rights reserved.

This paper introduces the statistical methods and application for the quantitative analysis of a site-specific landslide risk on the north slope of Lishan Mountain which is regarded being in an active state that could become a disastrous loess landslide. Based on the theory of probability statistics (Monte Carlo statistical methods) and the slope failure mechanical model, the overall failure probability and the local failure probabilities of the Lishan landslide were calculated. The results of the failure probability and stability analysis showed that the northern slope of Lishan Mountain is highly prone to lose stability during seasonal intense rainfall, whereas it is stable but still exhibits failure probability under arid conditions. The analysis of the safety margin and local failure probability evidenced that the upper part of the slope is less stable than the lower part. Under the intense rainfall condition, the local failure probability and hazard of local unstable failure of the slope will increase. According to the calculation results, it is deduced that the landslide on the north of Lishan Mountain will be a gradual process evolving from the local slope failure to an overall unstable failure.

By employing a complete observation system, the underground erosion in a typical large-scale crystalline schist landslide in Japan, the Zentoku landslide, was studied. It was found that the seasonal heavy rainfall is the main factor leading to the massive underground erosion. Two types of sediment discharge of the landslide were defined. Monitored data indicated that the movement of Zentoku landslide could be affected by the underground erosion following the concentrated heavy rainfall. The influence of the underground erosion on the movement of the landslide presents different features. For the sliding block of shallow and medium depth shear zones (5–20 m), the influence of the underground erosion is most outstanding, while it is negligible for the sliding block of thick soil and rock layers (>30 m). Finally, the rainfall thresholds for the Zentoku landslide, which concern the groundwater state, underground erosion and movement of sliding blocks, were provided to further establish the warning and evacuation system.

A quantitative description for the spatial distribution and the evolution of a crack network in mining rock stratum is one of the most difficult and fundamental problem in the subject of surface subsidence. In this paper, the physical models are employed to simulate the spatial distribution of a crack network. By using the fractal geometry, the self-similarity of spatial distribution of crack network is discovered. As a result, the conception of fractal crack network is proposed. Furthermore, the evolution of a crack network with the increasing of mining width is investigated. It is shown that (1) the spatial distribution of a crack network displays the fractal behavior, so, the fractal dimension can be used to describe quantitatively the evolution of the crack network, (2) the fractal dimension of the crack network increases with increasing of mining width, (3) the surface subsidence increases with the increasing of fractal dimension of crack network.