In this article, through aeolian sand sample study in Inner Mongolia Baotou area, to determine the aeolian sand maximum dry density and optimum moisture content. On this basis, the aeolian sand cohesion and internal friction angle were measured by the quick direct shear test when aeolian sand was at the optimum moisture content and near the most largest compactness. And the bearing capacity of retaining wall model which regarded aeolian sand as fillers was determined. Then bearing capacity change of aeolian sand wrapped before and after was compared. Experimental results showed that: when the aeolian sand was in the wet and compacted state, its cohesion was 3.31 kPa and internal friction angle was 36.8 degrees. The aeolian sand bearing capacity was 153.8kPa by the plate loading test. The aeolian sand wrapped with a geotextile bearing capacity was 194.1kPa. Through the aeolian sand research of Baotou area, it provides a useful reference for the construction of highway and railway and application of wrap-reinforced retaining wall which is a new retaining structure in the region, and the aeolian sand is treated as a special filling material in these structures.

This research is a contribution to the development of local materials especially in the development of a cellular concrete with dunes sand. This is an experimental study whose objective is to see the influence of the C/S (dosage of cement compared to sand) and the dosage of aluminum on the physico-mechanical and thermal performance of lightweight concrete cellular type. The results showed that the cement compared to the sand has a remarkable effect on the reaction and that on expansion the mechanical behavior as well as the dosage of aluminum in the composition of cellular concrete has a certain threshold Aluminium beyond which provides no relief benefits. Based on these results, the cellular concrete made from sand dune can be classified as light structural concrete with insulation suitable for very hot and arid environment of our region power.

In arid regions, groundwater resources are prone to depletion due to excessive water use and little recharge potential. Especially in sand dune areas, groundwater recharge is highly dependent on vadose zone properties and corresponding water fluxes. Nevertheless, vadose zone water fluxes under arid conditions are hard to determine owing to, among other reasons, deep vadose zones with generally low fluxes and only sporadic high infiltration events. In this study, we present an inverse model of infiltration experiments accounting for variable saturated nonisothermal water fluxes to estimate effective hydraulic and thermal parameters of dune sands. A subsequent scenario modeling links the results of the inverse model with projections of a global climate model until 2100. The scenario modeling clearly showed the high dependency of groundwater recharge on precipitation amounts and intensities, whereas temperature increases are only of minor importance for deep infiltration. However, simulated precipitation rates are still affected by high uncertainties in the response to the hydrological input data of the climate model. Thus, higher certainty in the prediction of precipitation pattern is a major future goal for climate modeling to constrain future groundwater management strategies in arid regions.

Sandy soils are extensively distributed in semiarid and arid areas in northern China and have low field capacity and water content. Reliable and precise equipment is essential to measure the water content of sandy soils accurately and continuously. The ECH2O EC-5 sensor is a promising soil moisture sensor for sandy soils. Although investigated intensively in laboratories, field-specific calibration of this sensor has not been conducted for sandy soils; therefore, the field performance of the EC-5 sensor remains unknown. This study aimed to: (i) calibrate the EC-5 sensor in the field for sandy soils, (ii) calibrate and evaluate the effects of soil temperature on EC-5 sensor measurements, and (iii) evaluate the performance of the EC-5 sensor for sandy soils. The difference between soil water content predicted by field calibration and gravimetrically derived volumetric soil water content (0.0048-0.1561 m(3) m(-3)) ranged from -0.004 to 0.002 m(3) m(-3). The EC-5 sensor should be subjected to field-specific calibration because sandy soils have low field capacity and low water content during the growing season. Soil water content was negatively correlated with soil temperature. At the 10-cm depth of fixed and shifting sand dunes, diurnal soil temperature fluctuations of +/- 10 degrees C underestimated or overestimated soil water content by 0.0021 and 0.0013 m(3) m(-3), respectively. The EC-5 sensor was used effectively in the Mu Us Sandy Land, Inner Mongolia, and revealed the soil water content dynamics in different soil depths after rainfall events.

The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engineering problems, namely low bearing capacity for shallow foundations and are not suitable as material for sub-base and road base. The use of this material in engineering practice needs improvement of their geotechnical properties. This paper investigates the effect of adding Portland cement to stabilize dune sand from the region of Natal, Brazil. Undrained triaxial tests were carried out to evaluate the effect of cement content on the geotechnical behaviour of dune sand-cement admixtures. Tests with admixtures with cement contents of 2.5, 5 and 10% of the dry mass of soil were carried out. Results showed that soil cohesion increased with increasing cement content. The friction angle of the admixtures was lower than that of the uncemented sand for cement content of 2.5 and 5% while It was larger than that of the uncemented sand for cement content of 10%.

The main factors affecting soil compatibility include moisture content, compaction work, soil type, grading and coarse material content etc.. The effects of compaction work are as follows: the stronger compaction work is, the more larger soil dry density is. The optimum moisture content decreases with the compaction work increasing. This paper mainly studies the effect of compaction work to aeolian sand compatibility. Its lay-down thickness is about 30-50cm when we use vibratory roller to compact aeolian sand in practical engineering. This paper analysis's and studies the maximum dry density and the optimum moisture content of aeolian sand in the middle region of Inner Mongolia, and achieves its lay-down thicknesses are 30cm, 40cm, and 50cm respectively at the optimum moisture content. We use 85kg vibration-impact rammer instead of YZ 18 vibratory roller to simulate the aeolian sand compaction effect at the optimum moisture content. The specification does not specify the number of compatibility times, but it is generally 3 to 5 times in the actual project. We choose the most suitable compatibility times and lay-down thickness through anglicizing the Aeolian sand compactness for vibration-impact rammer rolling on eloign sand 3 times, 4 times, and 5 times respectively at 3 different kinds of lay-down thicknesses. Through the study of the Inner Mongolia area Aeolian sand, it provides a useful reference for highway and railway construction in the desert area as well as the encapsulated layer thickness of reinforced retaining wall, a new type support structure.

The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

The Late Pleistocene was characterized by rapid climate oscillations with alternation of warm and cold periods that lasted up to several thousand years. Although much work has been carried out on the palaeoclimate reconstruction, a direct correlation of ice-core, marine and terrestrial records is still difficult. Here we present new data from late Middle Pleniglacial to Lateglacial alluvial-fan and aeolian sand-sheet deposits in northwestern Germany. Records of Late Pleniglacial alluvial fans in central Europe are very rare, and OSL dating is used to determine the timing of fan aggradation. In contrast to fluvial systems that commonly show a delay between climate change and incision/aggradation, the small alluvial-fan systems of the Senne area responded rapidly to climatic changes and therefore act as important terrestrial climate archives for this time span. The onset of alluvial-fan deposition correlates with the climate change from warm to cold at the end of MIS 3 (29.3 +/- 3.2ka). Strong fan progradation started at 24.4 +/- 2.8ka and may be related to a period of higher humidity. The vertical stacking pattern of sedimentary facies and channel styles indicate a subsequrent overall decrease in water and sediment supply, with less sustained discharges and more sporadic runoffs from the catchment area, corresponding to an increasing aridity in central Europe during the Late Pleniglacial. Major phases of channel incision and fan aggradation may have been controlled by millennial-scale Dansgaard-Oeschger cycles. The incision of channel systems is attributed to unstable climate phases at cold-warm (dry-wet) or warm-cold (wet-dry) transitions. The alluvial-fan deposits are bounded by an erosion surface and are overlain by aeolian sand-sheets that were periodically affected by flash-floods. This unconformity might be correlated with the Beuningen Gravel Bed, which is an important marker horizon in deposits of the Late Pleniglacial resulting from deflation under polar desert conditions. The deposition of aeolian sand-sheet systems (19.6 +/- 2.1 to 13.1 +/- 1.5ka) indicates a rapid increase in aridity at the end of the Late Pleniglacial. Intercalated flash-floods deposits and palaeosols (Finow type) point to temporarily wet conditions during the Lateglacial. The formation of an ephemeral channel network probably marks the warm-cold transition from the AllerOd to the Younger Dryas.

Eruptions resumed in 1730 in Lanzarote Island after a prolonged period of volcanic repose, probably encompassing the entire Holocene. This historical eruption involved about 3-5 km3 of basaltic pyroclasts and lavas, covering some 225 km2 (one third of the island). The accumulation of volcanic products had a strong impact on the landscape of this Miocene oceanic island. This was the second largest effusive basaltic event in recorded history, surpassed only by the 1783 Lakagigar eruption in Iceland. The central part of Lanzarote was mantled by lapilli-derived soils and aeolian sands, which provided a strongly contrasting ground for the basaltic products of the 1730 eruption. After the initial phase of the eruption, the style changed and new vents were controlled by a 15-km-long volcano tectonic zip-like eastwards-progressing fissure, with the first vents opening offshore west of the island. This abrupt modification may explain the progression of this eruption, from the average duration of historical Canarian eruptions (a few months), towards an exceptionally prolonged period of about six years. Besides duration, other outstanding features of the 1730-1736 eruption include the tholeiitic composition of lavas and the length of flows and lava tubes, particularly in the final stages. Initially, the eruption had a catastrophic impact on the resources of the island, since most of the farmland was covered by lavas and lapilli. However, agriculture significantly improved after the eruption with the introduction of dry farming, using lapilli cover as a new mulching technique.

The integrated crop-livestock-forest system can enhance the production of soybeans, meat and wood in regions characterized by sandy soils and warm climate. The aim of this study was to evaluate the yield of soybean, Urochloa ruziziensis grass and eucalyptus in an integrated system during the first four years after the establishment of eucalyptus in the northwestern region of Parana state, Brazil. The experiment was established in October 2009, using soybean (summer) -U. ruziziensis (autumn/winter) succession between single rows of Corymbia maculata (eucalyptus species). The spacing between tree rows and eucalyptus plants in the row were 14 and 4.2 m, respectively. Adjacent plots had the same soybean-U. ruziziensis succession, but without eucalyptus. The spatial variability of soybean grain yields and grass shoot dry matter production was evaluated with and without trees, and the data was analyzed using geostatistics, with the results expressed as spatial variability maps. The tree component did not significantly affect soybean yield in the first two growing seasons. In the 3rd and 4th growing season (2011/12 and 2012/13), the interference of eucalyptus reduced the soybean grain yield by 2.9 and 27.0%, respectively, and the effect was stronger close to the tree rows. In July 2012, the tree component reduced the shoot dry matter productivity of U. ruziziensis by 29.2%. At 19 and 35 months after eucalyptus planting, the cumulative wood volume production was 0.73 and 5.17 m(3) ha(-1), respectively.