In order to ensure the power supply, China is currently a large amount of crude oil exports from russia. Mohe the eve of Qing crude oil transport pipeline engineering need through about 500 km southwest of the eve of the lesser Khingan mountains and Nenjiang plains in the north, the eve of the permafrost and m of seasonal frozen soil region. Permafrost in the region is in gradually decline in the process, through years of frozen site with frozen soil engineering geological condition complicated, poor frozen earth scene development and engineering geological characteristics in permafrost region along there is the difference of the eve of the can of pipeline engineering and safety seriously threatened. Permafrost pipeline design and application objects have many special properties, on all sides and along the frozen pipeline oil temperature, thawing soil water heat condition will happen great influence, which directly affect the freezing and thawing soil physical and mechanical characteristics, coercion pipeline of all solid and structure after all. Thus, discuss the pipeline in permafrost engineering geological properties and engineering geological achievement coherence has important significance. Need to satisfy the pipeline in the early exploration stage of exploration evaluation and design and construction and permafrost test room of our hospital by Daqing Petroleum Engineering Co., Ltd. please, to take soil samples in accordance with the China Petroleum Pipeline Company in the China Russia crude oil pipeline (Mohe the eve of Qing period) Engineering permafrost engineering geological prospecting skills delineated (for Trial Implementation) "of frozen target put forward the technology request stop a considerable number of frozen soil special experiment. In this paper, first of all, through the process of various test methods of foundation soil along the pipeline between China and Russia from stop the coherent physical test, it is important to contain permafrost unfrozen water, specific heat of skeleton, volumetric heat capacity, thermal conductivity and diffusivity. These parameters are the main target of permafrost thermal research and engineering design in. This part focuses on the study of unfrozen water test. From the actually measured and analyzed the unfrozen water content measurement method with the calorimetric method, it is concluded that the principle of temperature measurement method hybrid concept of temperature grades, namely thermometry via the process Wu=a theta of a B notice form derived, reality is will beginning to thaw temperature unfrozen water content as arbitrary whims of negative temperature, the unfrozen water content. From the comparative analysis of the experimental data imitation, temperature measurement results uncertainty. In contrast, the calorimetric method on the basis of energy conservation principle to stop the derivation of the experiment and the formula for calculating the, truth experiment clear, and through a large number of experiments, the calorimetry test precision, satisfy the engineering design and application request. Take the six big calorimetry type pipeline in permafrost region of undisturbed soil sample for a comprehensive experimental research, summed up the temperature, soil and moisture influence on the discipline of the unfrozen water content. Temperature effect on unfrozen water content of important factors, with the decrease of temperature unfrozen water content reduced, differences of soil unfrozen water content of drastic change of temperature interval scale differences; six soil types in each temperature uniform unfrozen water content and temperature of reaction out, followed by soil evacuation of enlargement (plastic strengthen) unfrozen water content of growth. In the same negative temperature inorganic soil inorganic soil unfrozen water content is high, inorganic soil followed the content of inorganic matter enlargement, unfrozen water content increases; initial water content of inorganic soil unfrozen water content significantly abnormal effects. The initial water content is "clay silt and silty clay gravel sand on" sequentially affect the level of unfrozen water content. Through the process of unfrozen water influencing factor analysis, this paper summarizes the oil along the pipeline with the types of soil under the given negative temperature unfrozen water content represents values (average) and permafrost unfrozen water general formula, the power function wu=at a B in the parameters a, b values. This basically, the fitting results of clay, silty clay, silt and peat soil Wu WP t experience formula and at a given temperature of Wu Wo WP of two yuan for a linear regression equation. These experiences not only reflect the formula of soil, moisture and temperature effects on the unfrozen water also can be used for the engineering discipline, quickly identify the unfrozen water content reference. The fundamental of frozen soil thermal physical parameters including thermal conductivity, volumetric heat capacity, thermal conductivity, heat capacity of frozen soil skeleton. These parameters are calculated using the permafrost thermal target in the field, it is difficult to directly obtain, is measured in the laboratory. The way to take the frozen soil thermal physical parameters are: thermal conductivity of solid state by heat flow meter method determination, determination of thermal conductivity by normal condition method. Permafrost and frozen soil skeleton take specific heat volume heat capacity calorimetry. The greater Hinggan mountain permafrost peat peat, peat soil, clay, silty clay, silt and gravel sand a series of soil samples of frozen soil skeleton measurement of specific heat, through statistical analysis and comparison shows that, with particles become coarse and plasticity weaken and specific heat of frozen soil skeleton is gradually reduced. The frozen soil skeleton not only with specific heat values and plastic particles size, and inorganic matter content in soil. With the increase of the content of organic matter in soil, skeleton heat value enlargement: according to a 10 DEG C under the premise of the volumetric heat capacity experiment and calculation results, sub soil types comment debate with the relationship between the total water content and dry density. On four types of soil Cvf_W_ w of gamma D experimental data stop binary linear regression analysis, with the total water content and dry density growth and increase and linear coherence are very good in the frozen soil volumetric heat capacity. Joint unfrozen water and the skeleton of the specific heat measurement results together with soil total water content and dry density, which can be served as a negative temperature of frozen soil volumetric heat capacity calculation; frozen soil thermal conductivity were detected by flow meter method, through process experiments are given in the greater Hinggan mountain permafrost area five canonical soil lambda W Y D linear regression equation, and good coherence. The heat flow meter method can better remind freeze-thaw condition, water content, dry bulk density and soil as premise of the effect on the thermal conductivity and discipline. Most of the countries in the northern hemisphere for frost heave and thaw performance by. However, difficulty of frozen soils in the special situation of science and technology, especially cold geotechnical and pipeline engineering research is very lack. The second part of this article through indoor experiment of different kinds of soil stop frost heaving sensitivity analysis and pipeline area permafrost thawing settlement analysis. The model of soil material laboratory frost heaving imitate experiment, find out the soil conditions, water content, degree of saturation, density, such as identity and frost heaving ratio between the relationship. The separation of fine grain soil frost sensitive dominant element and effect of coarse grained soil rational analysis. Fine grained soil frost heave, containing water ray and plastic index is greater, the beginning of frost heaving of the higher water content, and frost heave becomes weaker; frost heaving of clay and silt with superplastic containing water (W 1 WP) change discipline basic similar, the same according to the soil of ETA ~ (w a WP) stop fine-grained soil frost heaving sensitivity classification; the frost heaving of fine grained soil is also affected by the saturation and compaction degree of, under the unified saturation. The soil frost heave followed the degree of compaction of the growth and decline, when the content of water will, fine grained soil frost heave rate will follow the growth of degree of compaction or saturation increases; the ETA ~ (w a WP) to Kd/Sr stop regression analysis. (w a WP) of frost heaving and contribution to than KD or Sr Nianye, explain superplastic water are fine grained soil frost heave of the dominant element. In the study of coarse grained soil frost heaving sensitivity and classification shows that soil moisture content is the occurrence of frost heave is the most important factor, while the influence of clay content infinite. From the silt to coarse sand, increasing the frost heaving ratio increases as the moisture content increased significantly. Through the process and the standard comparative study, that define the criteria of mud content boundary value is not suitable, the mud was lower than that of the delineation of the boundary value frost still exists in the case of bound water content, and even reach the strong expansion; standard in except silt coarse grained soil frost heave classification of surface, in classification of soil, water sediment boundary, freezing rate and moisture content relationship and boundary value is delineated, there are a lot of achievements significant deviation in peace, it is worth to discuss. To cause pipeline frost heave deformation of a 6m, the size of the foundation soil frost heave of the analysis shows that, along the segment AB in 6m depth range of silty clay in heave is important reason cause the frost heave of the section of the pipeline damaged. From the test material, frost heaving of silty clay along without significant discipline, the most likely is the premise of sections of the water supply has different effect be caused by. AB spread of coarse grained soil is sandy gravel and pebble rubble, gravel sand Nianye mostly belongs to the weak frost heaving, frost heave strength is determined to moisture replenishment premise, considering the pipeline operation can change the lower moisture premise, on some natural water content was low weak frost heaving zone also need to consider water fully evolved into frost heave and strong frost types. This section contains the gravel soil disposal by frost breccia. In this paper, the fine gravel, sand, silt, clay, peat clay soil and peat soil six samples of a total of 345 soil thawing settlement test, through the process of a large number of experimental data to carry on the analysis, proposed the permafrost thawing settlement coefficient and melting contraction coefficient of experiencing the positive way, and the permafrost thaw classification made a further study. Summarizes all kinds of soil thawing settlement coefficient A0 and the relationship between water content and dry density. Various types of soil thawing sensitivity is different. Silt thaw the most sensitive. Gravel soil in the premise with can sometimes occur can be indecent settlement, but, on the whole, the thawing settlement is smaller, ordinary is superior the frozen ground substrate; in permafrost thaw classification research in this paper than the existing criteria increased, peat clay soil and peat soil, the two soil types. In the regression analysis was proposed on the basis of the melting heavy grade line containing content and boundary of superplastic water content; melting contraction coefficient in the load test scale (200KPa) is not constant, but load increase and decrease followed by the, so after the melting of permafrost volume deposit shrinkage coefficient of MV is not the constant, and should be based on realistic pressure Nianye take small response value; summed up six types of soil MV Rd regression relation and digital form and can be used for the engineering estimate MV application. Frozen soil is a very sensitive to temperature and soil temperature, followed by the differences of the physical and mechanical properties will produce very big change. Laying the oil transportation pipe in permafrost regions will damage between frozen soil and air to have set the heat balance and the soil temperature and freezing and thawing process produces a big change, thus the pipeline the basic stability of the formed adverse effects. Is, for pipeline engineering construction and operation characteristics of the foundation soil temperature pipeline design application in the period of the field make major significance notice. The pipeline around the soil temperature field to establish a fantasy physics model. Given a certain model assumptions, on the basis of coherent response documents and materials design are the boundaries of the premise, planned around the pipe soil temperature field changes. Do not consider the effect of the oil temperature and a negative temperature temperature of two kinds of situations on the temperature field of frozen soil to stop speculation. From the pipe cross-section under axial temperature freezing and thawing process line to see, pipeline in operation before 25 years, have you, seasonal frozen soil depth in 7 meters you change, and in calculating after 25 years, seasonal frozen soil thaw depth is decreasing year by year, explaining seasonal permafrost in the year of recession. Calculation of 25 years ago, the lower limit of permafrost in a declining trend, also the upper limit of permafrost in gradually lifted, explaining in permafrost in year after year setback; figuring to 27 years, permafrost complete backward for seasonal frozen soil. Is to, in the global warming of the weather of the eve of the premise, and the low-temperature Unstable Permafrost by a greater impact, permafrost retrogression to season frost until the complete backward. The temperature in all process is followed by calculating geothermal field changes, in fact is not a constant temperature. By the cross section of the pipeline axis depth bias to make temperature depth curve shows, pipeline interface intermediate temperature with the running time of change discipline, at a uniform depth geothermal into increasing trend, 10m scale temperature change is the eve of the gradient, 10m temperature change gradient gradually decreases. In more for the lower limit to run length decreases, explain in temperature under the influence of the minimum wage rise year by year. 目录: |
