長期凍土 的英文怎麼說
中文拼音 [zhǎngqīdòngtǔ]
長期凍土
英文
perennially frozen ground-
This paper unfolds engineering disposition and theoretical research of negative temperature high performance concrete ( nthpc ) with the damage of many factors motivation, the project background based on qing - zang railway engineering, which is one of four - emphasized engineering during the tenth five - plan. due to the difference of environment of construction and service between nthpc and ordinary concrete, and therefore durability of nthpc is required to higher level. at a first, nthpc must avoid frozen damage at early age and possess anti - freezing property at later period, in order to meet engineering practicable application need, and this are two emphasized and difficult problems, as for nthpc ; by means of mechanism analysis about deicing - agent ingredient and anti - freezing at early period, adopting composite technique routine of mineral addition + anti - freezing element + water - reducer4 - air - entraining + anti - erosion of steel component etc, based on orthogonal experimental approach, fd - 1 composite functional admixtu re was manufactured, which has more property and orientation on qing - zang railway
負溫混凝土由於和普通混凝土在施工環境及服役環境上存在的差異，因此表現為比普通混凝土更為較高的耐久性要求；負溫混凝土首先要避免早期的凍害以及具備長期抗凍性能，才能夠滿足工程實際應用的要求，這也是負溫混凝土必須解決的兩大技術關鍵；通過對目前常用防凍劑組分作用機理的分析研究及混凝土早期防凍機理探討，採用礦物外加劑+防凍組分+高效減水劑+引氣+阻銹組分功能復合的技術路線，通過正交試驗設計復配了適應青藏鐵路工程要求的專用多功能復合型外加劑fd - 1 ；並在此基礎上配製不同等級負溫高性能混凝土，開展一系列包括硫酸鹽侵蝕、氯離子滲透、抗凍融循環、收縮及耐磨性等耐久性能研究；通過對fd - 1組分和摻量的調整，優化負溫混凝土在施工特性、力學指標和耐久性三個方面的兼容、協調性。Permanently frozen subsoil, occurring throughout the polar regions and locally in perennially frigid areas
永凍土永久冰凍的下層土壤，出現在整個北極地區和部分長期寒冷的地區The results demonstrate that the upper limit of permafrost in this area had declined from 1970s to the middle phase of 1990, and permafrost has appeared degenerate tendecy, but since middle 1990s, permafrost have a stable state ; ground temperature of roadbed near the earth surface is higher than that of the natural ground, thawing time of roadbed near the earth surface is longer than that of the natural ground, the heat income within the permafrost is greater than the heat release from the permafrost during anannual period, the heat accumulation within the permafrost is temporarily appeared as temperature rising, but with the heat accumulation within permafrost growing up year by year, permafrost temperature will become higher gradually, and strong thawing of permafrost could be happened in the region
結果表明：風火山地區從20世紀70年代到90年代中期凍土上限下降，凍土出現退化現象，從90年代至今凍土趨于穩定；路基近地表地溫明顯高於對應天然地表下的地溫，路基近地表經歷的融化期長于對應天然地表，進入多年凍土區的熱收支也呈現出吸熱明顯大於放熱的周期性變化，進入多年凍土的熱積累暫時以增高地溫耗熱為主，但隨著凍土吸熱量的逐年積累、凍土溫度的不斷升高，本區凍土可能發生強烈融化。It was shown that salt expansion value of low liquid - limit clay was accumulated before the sixth freezing and thawing cycles, but the increment of salt expansion was reduced gradually with increasing cycles ; the salt expansion accumulation of low liquid - limit clay could be separated into three phases ; the deformation of clayey sand was mostly frost heave and subsidence under cycles, and collapsibility value of clayey sand was accumulated with increasing cycles ; the variation of salt expansion ratio and collapsibility ratio was a parabolic function of freezing and thawing cycles
試驗結果表明：低液限粘土前五次凍融循環過程中鹽脹具有較好累加性，隨著凍融循環次數的增加，鹽脹量增長速度逐漸降低；含砂低液限粘土的鹽脹過程可以被分為三個階段；粘土質砂在凍融循環過程中的變形主要為凍脹和沉降變形，具有較好的溶陷累加性；低液限粘土、含砂低液限粘土的鹽脹率和粘土質砂的溶陷率與凍融周期之間的關系符合二次拋物線變化規律。Many places in our country have long cold season, because of construction period limit, concrete construction in winter is not avoided, knowing concrete construction cold principle in winter is important, so relevant winter concrete construction method must be selected according to local conditions
摘要因為冬季施工有較長的寒冷季節，由於工期的制約，冬季進行混凝土施工不可避免，故而了解混凝土施工的冬季凍害原理並根據當地的具體條件選擇適當的冬季施工方案就尤為重要。The result indicated that, mix the mineral mixture of fly ash, flag into concrete can optimize the concrete pore structure, improve the concrete compressive strength and impermeability, and along with the age increment the improvement become more obviously ; after saturated freezing and thawing, the concrete pore structure changed apparently, total porosity increased, macro porous quantity rapid increased, small pore quantity reduced, mean radius and most probable aperture increased ; and the more saturated degree, the more obviously destructive effect
研究表明:在混凝土中摻加粉煤灰、礦渣等礦物摻合料優化了混凝土的孔結構，提高了混凝土的抗壓強度和抗滲性能，且隨齡期的延長這種改善作用更加明顯;飽水凍融后混凝土的孔結構變化明顯，總孔隙率增加，大孔數量急劇增大，小孔數量減小，平均孔徑和最可幾孔徑增大;且飽水程度越大，這種破壞作用越明顯。Based on five years regional water - salt monitoring data and related hydrological and weather information in the smaller scale experiment zone ( shahaoqu ), the regional water - soil ( salt ) environment regime including grounder water table depth, water quality, superficial layer ( 0 - 40cm ) and middle layer ( 40 - 70cm ) soil moisture and saline concentration are simulated, tested and predicted using bp model. at the same time, the rbf model is be used to calibrate the results of bp
以一個小尺度試驗區的多年區域水鹽監測資料及水文氣象資料為建模依據，對試區非凍期（作物生長期）的地下水位、地下水質、土壤水鹽（ o - 40cm ， 40 - 70cm ）的水-土（鹽）環境狀況進行了較為深入全面的模擬預測，並進行了rbf模型預測結果的對比。分享友人