The calculation and analysis of ecological footprints,diversity and developm ent capacity of China

T he ecological footprint of China's provinces is calculated in this pap er. In general, China's development is not sustainable because its ecological footprint is beyond its bio-capacity. The sustainability status of each pr ovince in China is presented. Ulanowicz's development capacity formula w as introduced to discuss the relationship of development and ecological footprin t's diversity. The diversity of ecological impacts is related to the e fficiency with which an economy uses the source and sink services of the environment and, in this view, should be a factor in economic output. Developme nt capacity, calculated from the ecological footprint and its diversity , is used to examine the relationship of economic output with the st ructure of the ecological footprint. China and its provinces are prese nted as a case study to investigate this relationship. The analysis s hows that footprint capacity is significant in predicting economic outp ut. Increasing the ecological footprint's diversity is presented as another way to increase development capacity.

The Influence of Earth Temperature on the Dynamic Characteristics of Frozen Soil and the Parameters of Ground Motion on Sites of Permafrost

Earth temperature is one of the most important factors influencing the mechanical properties of frozen soil. Based on the field investigation of the characteristics of ground deformation and ground failure caused by the M S8 1 earthquake in the west of the Kunlun Mountain Pass, China, the influence of temperature on the dynamic constitutive relationship, dynamic elastic modulus, damping ratio and dynamic strength of frozen soil was quantitatively studied by means of the dynamic triaxial test. Moreover, the characteristics of ground motion on a permafrost site under different temperatures were analyzed for the four profiles of permafrost along the Qinghai Xizang(Tibet) Railway using the time histories of ground motion acceleration with 3 exceedance probabilities of the Kunlun Mountains area. The influences of temperature on the seismic displacement, velocity, acceleration and response spectrum on permafrost ground were studied quantitatively. A scientific basis was presented for earthquake disaster mitigation for engineering foundations, highways and underground engineering in permafrost areas.

Simulating Experiment for Temperature Field of Frozen Subgrade Using RegulationTubes

The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot of the embankment. By means of this equipment two simulating experiments of controlling temperature filed of frozen sub- grade were carried out in the laboratory.One method is to collect natural cold energy,and the other one is to collect natural cold energy ccompanied by artificial refrigeration simultaneously.The result indicates that the latter is an ef- fective method for maintaining the stability of the frozen subgrade.

THE REAL IN TIME CT MONITORING OF THE MESO-DAMAGE EVOLUTION LAW OF SANDSTONE UNDER TRIAXIAL COMPRESSION

The real in time computerized tomography (CT) testing of the meso damage propagation law of the whole sandstone failure process under triaxial compression has been completed using the newest specified triaxial loading equipment corresponding to the CT machine. Through the CT scanning, the clear CT images which include from the microcracks compressed stage to growth stage, bifurcation stage, development stage, crack fracture stage,the rock sample failure until to unloading stage in the different stress states were obtained. The CT values, CT images and the other data have been analyzed. Based on the results of the CT testing of meso damage evolution law of rock,the stress threshold value of meso damage of rock is given, and the stress strain complete process curve of rock is divided into some sections. The initial rock damage propagation law is given in this paper.

Changes in permafrost ecosystem under the influences of human engineering activities and its enlightenment to railway construction

Through the investigations of sample belt transects and sample quadrats, the variation characteristics of the disturbed ecosystem by highway engineering in the permafrost region along the Qinghai-Tibet highway line were studied from the ecological elements such as permafrost eco-system, community type,biodiversity and biological produc-tivity and biological habitat conditions including soil envi-ronmental conditions and permafrost environmental condi-tions. The results show that in the sense of biology the resto-ration of high-cold steppe ecosystem was much better than that of high-cold meadow ecosystem after nearly 5 a of natu-ral reconversion.This is mainly manifested in several resspects:The dominant plant species of the high-cold steppe have occurred or even held a predominant position; local zonal biodiversity and population abundance have reached or even exceeded the level of the undisturbed natural steppe system.Viewed from soil environment change, organic matter content in the disturbed high-cold steppe on an average de-creased by 61.5% and total N content decreased by 52.51%,but the nutrient regime of surface soil layer in most of the region corresponded to that of main grassland soil types in the arid region,which is favourable to the growth of cold-resistant species. The mean nutrient contents of the dis-turbed high-cold meadow soil(Gelic cambosols)were higher than those of natural cryic aridsols. The maintenance of the integrity of meadow soil structure is crucial to the restoration of high-cold meadow ecosystem.However,the distribution and maintenance of high-cold meadow ecosystem were closely related to the permafrost environment,the restoration degree of the disturbed high-cold steppe ecosystem did not show an obvious restrictive relation with permafrost environ-ment.Once the permafrost environment was destroyed by the engineering activities,the high-cold meadow ecosystem was very difficult to rehabilitate. From the comparison of the variation laws of the ecosystem along the Qinghai-Tibet highway line, the authors put forward two enlightenments for the eco-environmental protection in the construction processes of the Qinghai-Tibet railway.

Evaluating model of frozen soil environment change under engineering actions

The change of frozen soil environment is evaluated by permafrost thermal stability, thermal thaw sensibility and surface landscape stability and the quantitatively evaluating model of frozen soil environment is proposed in this paper. The evaluating model of frozen soil environment is calculated by 28 ground temperature measurements along Qinghai-Xizang Highway. The relationships of thermal thaw sensibility and freezing and thawing processes and seasonally thawing depth, thermal stability and permafrost table temperature, mean annual ground temperature and seasonally thawing depth, and surface landscape stability and freezing and thawing hazards and their forming possibility are analyzed. The results show that thermal stability, thermal thaw sensibility and surface landscape stability can be used to evaluate and predict the change of frozen soil environment under human engineering action.