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In the past 30 years, because of built-in advantages, energy saving, pollution control, and sustainability, the energy pile system has had a rapid development around the world. Many scholars did numerous researches on the parameters’ optimization, heat exchange efficiency, and structure-soil response. Also, the researches of evolutional GSHP system using high temperature in deep mine and lager collection surface of tunnel lining were learned. At present, most of researchers are discussing the geothermal collection for the heating or cooling the building, and plenteous and significant research achievements have been obtained. It is a novel attempt to apply energy pile to geotechnical engineering, and good results have been achieved in engineering practice in Northern China. The area of northern China is a typical seasonal frozen region: the high temperature in summer and the cold weather and accumulated snow in winter will result in huge challenge and resource consumption of maintaince on highway tunnel, pavement, and other geotechnical engineering facilities. In this paper, taking example of using the geothermal heat exchanger to melt snow, the novel idea of using energy piles to prevent track in summer and crack in winter of pavement, and guaranteeing the safety of frost crack on tunnel lining were discussed. Also, through simulation research, we propose a buried pipe form with good heat transfer uniformity-spiral buried pipe, which has better engineering applicability. This shows us that the application of energy pile in geotechnical engineering will provide solutions to geotechnical problems, which will have a brilliant future.

The aim of this study was to examine certain properties of sessile oak wood (Quercus petraea (Matt.) Liebl.) with frost cracks, such as density (&rho, ), modulus of rupture (MOR), modulus of elasticity (MOE), and compressive strength in all anatomical directions and to compare it with control trees without frost cracks. Oak with frost cracks had a higher wood density (&rho, = 765 kg &times, m&minus, 3) than the control (&rho, = 650 kg &times, 3). However, despite its lower density, the control oak was characterized by noticeably better mechanical parameters, with the exception of the compressive strength in radial and tangential directions. Differences in mechanical parameters reached up to 26%. The tests were performed on wood taken from trees with frost cracks that formed over 10 years to several decades ago. Frost cracks can render wood vulnerable to fungi growth, which leads to rotting and discoloration. Differences in strength were found on samples with no visible signs of decay, as they were cut at a distance from the crack. Nonetheless, the observed differences in strength allowed us to conclude that the shreds of fungi, as well as decay, may occur in the entire volume of the frost-damaged log. Such wood is, therefore, of a lower quality than that made of logs without any frost damage. Trees with frost cracks should be progressively be felled during the periodic intermediate cutting, as their wood quality may systematically deteriorate over the years.

An idea of B.N. Dostovalov’s to represent a mass of frozen soil, prior to its failure, as an elastic brittle body is considered. An analytical estimate is provided of the temperature field and thermoelastic stresses occurring in the near-surface layer as a result of sudden atmospheric cooling. The principal parameters of primary frost cracks are calculated. An analysis is presented of their dependence on mechanical and thermophysical soil properties and baseline data.

Frost crack represents one of the main defects which affect European beech wood quality. Therefore, the purpose of this paper is to improve the knowledge regarding both the impact of frost crack on European beech wood quality and the frost crack characteristics which affect wood quality. In order to do this, nineteen European beech trunks with frost crack have been studied. Each trunk has been cross-cut every 1 meter and the characteristics of frost crack and frost crack star-shaped heart have been measured in each cross-cut section. The defects which accompany frost crack have also been identified in each crosscut section. Moreover, the possibility of determining these defects using the IML RESIF500 – S Resistograph has been tested. The research has emphasized the existence of statistical correlations between frost crack star-shaped heart expansion, frost crack rib prominence and frost crack length. These correlations are expressed by multiple linear regressions. The presence of defects which affect wood structure leading to a decrease in penetration resistance can be determined accurately with the resistograph. Decay (in frost cracks older than 8 years) and ring shake have been identified as the most frequent defects which accompany frost crack. The measurements made on the frost cracks studied have been gathered in a graph which shows frost crack impact on European beech wood quality. The results obtained lead to the improvement of the criteria of European beech wood quality assessment by expanding the already existent knowledge and by identifying new aspects which may complete standing wood quality determination and sorting methods.

Silver birch ( Roth) seed origins from the Baltic countries and from Finland were compared in terms of growth, wood density, bark thickness and the incidence of darkened core wood, frost cracks and decay, and the effect of seed origin latitude was examined in two Finnish provenance trials. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N from the Baltic countries and Finland. The trials, measured at the age of 22 years, were located at Tuusula (60°21´N), southern Finland and at Viitasaari (63°11´N), central Finland. The Baltic origins were superior to the Finnish ones in the southern trial regarding height, whereas in central Finland the Finnish origins grew better. There was no consistent difference between the Baltic and the Finnish group of origins in wood density. Bark thickness decreased with increasing seed origin latitude. The Baltic origins had significantly thicker bark than the Finnish origins. A moderate positive correlation was detected between the seed origin latitude and the incidence of darkened core wood in the southern trial, where the darkened core wood was more common in the Finnish origins than in the Baltic ones. The highest proportion of trees with frost cracks was detected in the south-western Latvian origins growing in central Finland. Seed transfers from the Baltic would have an increasing effect on the bark thickness of birch logs, but no or only minor effects on wood density. Based on our results, there is no reason to recommend the use of non-native Baltic seed origins in Finland instead of the native locally adapted seed sources.Betula pendula

Freeze-thaw action in fractured rock mass is discussed. Moist rock exposed to subfreezing temperature would suffer from freeze-thaw deterioration, which would pose serious threat to the stability of geotechnical engineering. Some key factors influencing freeze-thaw action in rock mass is analyzed, such as temperature, freezing rate, freeze-thaw cycles and porosity of the rock. Further more, using the theory of physical chemistry, the freezing point and frozen ratio were derived. Finally, the model of frost crack was built by ANSYS and then imported into FLAC3D by converting procedure. The stress field, temperature filed as well as the normal and shear stress on surface of the cracks were demonstrated. The effect of freezing pressure is reflected in the results.

Water-bearing rocks exposed to freezing temperature can be subjected to freeze–thaw cycles leading to crack initiation and propagation, which are the main causes of frost damage to rocks. Based on the Griffith theory of brittle fracture mechanics, the crack initiation criterion, propagation direction, and crack length under freezing pressure and far-field stress are analyzed. Furthermore, a calculation method is proposed for the stress intensity factor (SIF) of the crack tip under non-uniformly distributed freezing pressure. The formulae for the crack/fracture propagation direction and length of the wing crack under freezing pressure are obtained, and the mechanism for coalescence of adjacent cracks is investigated. In addition, the necessary conditions for different coalescence modes of cracks are studied. Using the topology theory, a new algorithm for frost crack propagation is proposed, which has the capability to define the crack growth path and identify and update the cracked elements. A model that incorporates multiple cracks is built by ANSYS and then imported into FLAC3D. The SIFs are then calculated using a FISH procedure, and the growth path of the freezing cracks after several calculation steps is demonstrated using the new algorithm. The proposed method can be applied to rocks containing fillings such as detritus and slurry.

Due to its high strength, good durability, concrete is widely used in various types of buildings and structures. With the continuous development of engineering and technology, all kinds of new, unique shape structure, the use of mass concrete structure is more and more widely. But big volume concrete block, its thermal performance is poorer, inside the concrete hydration heat accumulation is difficult to spread, surface heat faster, the center temperature and the surface temperature of the temperature difference will cause concrete crack; In addition, the elastic modulus, coefficient of relaxation, could also change along with the change of temperature, time, you can always cracking of concrete. How to control the mass concrete cracking, is always the key and the difficulty of structure and construction. In this paper, on the basis of a lot of practice, summarizes the characteristics of mass concrete, concrete cracking reason, and from two angles of the design and construction, analyzes the limited measures of mass concrete cracking control. For real reflect the temperature field and temperature stress of engineering, based on the large finite element software ANSYS, simulation analysis of mass concrete temperature field and temperature stress, and the following conclusions. Through the contrast analysis, concrete temperature crack control to set according to different season, summer temperature is higher, to take appropriate cooling method to control, to avoid late concrete internal temperature rapidly reduced. And to pay attention to the thermal insulation of concrete in winter, avoid frost crack.

In northern Hokkaido, only a few absolute ages have been obtained from periglacial phenomena, which characterize the landscape of the area. The present lack of age constraints has prevented studies on precise geomorphic development and terrestrial palaeoenvironmental reconstruction in this area during the last glacial period. The aim of this study is to apply optically stimulated luminescence (OSL) dating and AMS14C dating methods to establish the chronology of fossil frost cracks, periglacial slope deposits, and involutions from a region in northern Hokkaido including Rishiri Island. The samples for OSL dating were taken from five localities. To compare OSL and AMS14C aging, a loess sample for OSL dating and a charcoal sample for AMS14C were collected at Loc. 3 from the same homogeneous silt layer. Besides, at Loc. 4, an OSL and a charcoal sample were collected from a channel deposit. These charcoal samples were subjected to AMS14C dating as independent age controls. OSL ages and calibrated 14C ages from the charcoal were in close agreement in each locality. These results suggest that OSL ages of loess and channel deposit in this study are reliable. From Horonobe (Loc. 1) in the southern Soya hills and from Rishiri Island (Loc. 2), two OSL ages from periglacial slope deposits indicate 21 and 22 ka. Their OSL ages, showing involution from east of Wakkanai (Loc. 3), suggest that the sand was deposited between 54 and 42 ka and that the involution was formed afterwards before 13 ka. At Loc. 4, the fossil frost crack southeast of Cape Soya was formed between 120 and 13 ka, and at Loc. 5, the fossil frost crack was formed between 24 and 15 ka. These results indicate that many periglacial phenomena were possibly formed at about 20 ka in northern Hokkaido.

Tectonic and soil mechanics investigations of a strongly plastic clay (Miocene ‘Mica Clay’) led to the detection of strain phenomena induced in connection with the formation of Elsterian buried channels. A microjoint system with randomly distributed fissures is thought to result from early Elsterian dessiccation and frost crack formation. It occurs frequently in the upper part of the clay horizon. A younger joint system, which is encountered throughout the entire clay body, comprises macrojoints arranged in three joint sets. The evidence strongly suggests that they were formed by gravitational and kinematic loading of the clay body by overriding ice. The macrojoints display various secondary alterations such as slickensides, escarpments, shear zones, erosive and pressure zones, the formation of which is seen in context with the channel incision. Investigations into the genesis of these alterations indicate a strong horizontally-orientated stress induction lateral to the channels, which resulted in stiffness modulus anisotropy. It has also caused a horizontal compression of the clay body, which at that time was already consolidated through ice overburdening. Horizontal compression of the clay led to evorsion of pore water eroding clay particles from the joint walls. Lower water content of the clay, in combination with increased dry unit weights, are found adjacent to the channels today.

Wedge-shaped structures are described from three sites in the central Wielkopolska region (central-west Poland) in two main positions: (1) within fluvioglacial deposits below the Weichselian subglacial till and (2) within recessional deposits above this subglacial till. The wedges are interpreted as ice-wedge pseudomorphs (Rensko site), relict frost cracks (Tomice site) and thermokarst-affected ice-wedge pseudomorphs (Annowo-Kiszkowo area). The pseudomorphs suggest that thermal-contraction cracking occurred in the region in front of the advancing Weichselian ice sheet, as well as following its recession. Frost structures, which are interpreted as having degraded slowly, were much more affected by thermokarst processes (Annowo-Kiszkowo area) than those in the Rensko and Tomice sites which probably thawed rapidly, due to an insulating and warming effect of the overlying ice masses. The development of ice wedges was influenced by wet conditions in former depressions between ice-cored ridges or by large amounts of meltwater in the proglacial environment. These periglacial features support previous hypotheses that climatic conditions in the Wielkopolska region after the last ice-sheet recession changed gradually from glacial to periglacial. Copyright © 2009 John Wiley & Sons, Ltd.

Frost cracks are common in northern hardwood stands near their northern range limits. Although they have long been attributed to the regional climate, temperature fluctuations result in surface cracks largely when internal wounds are present. We examined the relationship between the proportion of trees with frost cracks and both tree-level diameter class and stand structural characteristics in primary stands with a history of minimal logging (n = 4) and 67- to 97-year-old second-growth stands subjected to past heavy partial cuts and high grading (n = 8). We hypothesized that frost crack incidence would (1) be greater in the second-growth stands and (2) be associated with differences in structural attributes between the two stand types. High levels of frost cracking in primary stands indicated that cracks are not completely avoidable. However, the proportion of trees with frost cracks was significantly higher in second-growth than primary stands, particularly on small-diameter trees. For example, the odds for frost cracking were 1.66–3.74 times greater in second-growth than in primary stands in the 15-cm diameter class, but were not different in the 45+-cm diameter class. Frost cracking was positively associated with increasing diameter in both stand types. Structural characteristics reflecting tree size, stand basal area, and basal area of hardwoods were positively associated with the proportion of trees with frost cracks in second-growth stands but not in primary stands. Although the basal area of conifers was negatively associated with frost cracking, the effect was likely due to a reduction in hardwood basal area in the vicinity of conifers. We suggest that greater frost crack incidence in second-growth stands is likely a consequence of injuries to residual trees during selective logging.

ABStr Act : Frost cracks which originated in birch due to bending during long-term icing in winter 1995/1996 became the place of entrance for the attack of birch stems by Piptoporus betulinus (Bull. ex Fr.) Karst. and subsequently for one of the causes of birch stand disintegration in the Krusne hory Mts. The hypothesis is substantiated on the basis of regularities of the frost crack dispersion in the stem profile, frequency of occurrence related to the stand age, altitude and cardinal points. The number of frost cracks increased with the transect profile altitude 700-850 m. One crack on the birch stem predominated (73%) while the higher number of frost cracks occurred at altitudes > 800 m. In stands younger than 20 years, frost crack damage was higher (34-47%) than in older stands (14%). Frost cracks occurred in the lower part of stems with the highest bending stress.

Ground thermal conditions in a frost-crack polygon, a palsa and a mineral palsa (lithalsa) in the discontinuous permafrost zone, northern Sweden

Through five years (1996–2000), experiment, the growth characteristics and resistance to insect and cold of the seven poplar varieties includingP. popularis, P. opera, P: pseudo-simonii, P. beijinensis, P. bolleana, P. x euramericana andP. simonii, which were planted in loess hilly land in northwest Shanxi Province, were tested under different planting densities and site conditions. A randomized block design and three times repetition were adopted in the test. Based on the test results in arid and cold area of the northwest Shanxi, the hybrid poplar trees takingPopulus cathaysna as their female parent could be selected for afforestation, such asP. popularis andP. opera, and the growing space of single plant should be larger than 20 m2.P. bolleana as an introduced tree species grows well in this area, but its growth is likely affected by, ground water condition. On the site with relatively abundant soil water,P. bolleana usually suffer from frost crack at its trunk base. As a result,P. bolleara is suited to planting in the site where is short of soil water.P. x euramericana is not suitable for large-scale afforestation, especially in arid slopes and ridges of loess hilly land.

To develop and apply biogas, we utilize crops which are discarded, lower energy consumption, and reduce environmental pollution. However, due to the low temperature in cold areas in winter, the gas production rate of biogas digester is too low, and the biogas digester cannot be even utilized normally because of frost crack. Through building the combined warming system with solar energy and biogas boiler, the temperature in the biogas digester is tested and analyzed, and the matching ways of combined operating with area of solar collector and biogas boiler are determined. The results indicate that combined warming system can keep the biogas digester in a better fermentation temperature, which will ensure a continuous and efficient gas production rate and resolve the bottleneck problem of being unable to use biogas normally in cold areas in winter.

The actual distribution of the active mycelium during the process of decay in living trunks of various timber trees, and the process of such decay in the production of "heart-rots," is still poorly understood. If one examines the literature on the subject, it soon becomes evident, however, that sufficient data are at hand to conclude that the relation of any specific heart-rotting fungus to a specific tree is either specific itself or belongs to one of a group of type reactions. We are far enough in the study to realize that generalizations on these reactions are impossible. In the study of a rot caused by Trametes robiniophila Murr., we paid little attention to the number of trees affected or to the question of the value of locust timber. The inroads of the locust borer, and, in the more southern distribution of the locust tree, the abundant heart-rot due to Fomes rimosus, both loom as so much more important enemies to be controlled before the locust tree can find its rightful place in lumber economy, that it seems futile to attempt to make an important case of the rot in question. Our attention was therefore directed to an analysis of one case: the macroscopic and microscopic characteristics of the rot; its mode of advance; the distribution of the mycelium in the various portions of the affected trunk; and its effect on the various elements of the wood. That the white heart-rot of Robinia Pseudo-Acacia L. is quite frequent in southern Michigan there is no doubt. Its presence is not to be reckoned by the number of sporophores observed, since it appears to fruit sparsely, and when it does the sporophore rarely lasts more than one season or is soon attacked by insect enemies or disintegrated by wind and weather. The black-locust tree is found scattered along some of the Ann Arbor streets, and not a few show symptoms of heart-rot. From year to year sporophores may be noticed on some of them, and the tree selected for study had had a large yellowish sporophore on it the year before, and at the time of cutting had produced another from an old frost crack that had almost healed over; in addition, signs of several old scars left by former sporophores were still distinguishable on the trunk. Although the tree was suffering from both borer attacks and the heart-rot, as shown by a number of large dead branches and the straggly condition of the crown

Field observations in the Mackenzie Delta area largely substantiate Lachenbruch's theoretical considerations of thermal contraction crack development. Frost crack patterns, representing the incipient stage of tundra polygons, were observed on both bare and vegetated surfaces of low alluvial flats and sandspits of three islands. Individual polygons, where developed, ranged in size from 20 to 30 metres diameter on bare surfaces to 2 to 3 metres on sedge-covered areas, and 80% of the angular intersections measured were of orthogonal type. Most cracks exhibited random orientations, except in close proximity to water bodies where tendencies toward normal and subparallel orientations occurred.