【正文】 athering. The former is called “original frost heaving, the latter is called “migrated water frost heaving or segregating condensation frost heave The countermeasure to ground freezing heave and thaw settlement ? 在工程中原位凍脹很難消除（除非對土壤孔隙水做某種處理），主要是盡可能減少遷移水凍脹。 ? The magnitude both soil frost heaving and thaw settlement is very important to the related buildings/structures in municipal ground freezing. Therefore, more attention must be paid to the related buildings/structures safety requirements and soil itself frost heaving and thaw characteristics while GFM is applied in the freezing sensitive soil. Some necessary measures may be taken for the safety on the base of the estimated quantity of frost heaving and thaw settlement through test and engineering analogy. The countermeasure to ground freezing heave and thaw settlement ? 凍脹的主要原因是液態(tài)水凍結(jié)后變成固態(tài)冰 ,其體積增加9%產(chǎn)生“凍脹”。因此，在那些凍敏性土壤中應(yīng)用凍結(jié)法，要特別注意相關(guān)聯(lián)建 /構(gòu)筑物安全要求和土壤本身凍脹和融沉特性，通過試驗和工程類比估算出凍脹和融沉量。 Both the longterm strength and creep property of frozen soil are very important except the pressive strength, these parameters decide the success of the freeze shaft lining. 而在市政工程的地層凍結(jié)中，除了凍土抗壓強度外，有時候的抗拉強度、抗剪強度、抗彎強度極為重要。 , or the triaxial strength is not related to confined pressure. These kinds of so called “unusual features ” are just usual, all are the same as the triaxial shear strength data that we found under undrainage of air and water at 10 ℃ (the dotted line). 176。 Some unusual features can be found that triaxial strength of the clay are almost constant, or Mohr39。圖顯示：凍結(jié)固結(jié)粘土在 5， 15℃ 試驗溫度下的內(nèi)摩擦角 φ≤0 ；即其三軸抗剪強度與圍壓無關(guān)。這種最后遠(yuǎn)離說明負(fù)溫和“冰融”作用都很大，這與實際情況不符 。圖中看到，剪應(yīng)力峰值過后隨著 p值不斷升高而加速這種冰的融化。將這些數(shù)據(jù)繪于 pq坐標(biāo)平面如圖所示 溫度02468100 3 6 9 12 15 18八面體上p MPa剪應(yīng)力q MPa5度10度15度20度25度 1 0 度up=(σ1+2σ3)/3 q=σ1σ3 本試驗僅限于 σ3≤ (cont.) The main points for tests of artificial frozen soil mechanical properties ZJ290 frozen clay triaxial tests under drainage and undrainage condition Constant axial strain rate %/min (cont.) The main points for tests of artificial frozen soil mechanical properties 0123456780 5 10 15 20 25 30八面體上p MPa剪應(yīng)力q MPa2℃℃5℃7℃蘭州凍砂瞬時三軸剪切強度結(jié)果。到目前，試驗和工程應(yīng)用人員還沒有充分認(rèn)識到這一點。如果在凍土試驗前不盡可能恢復(fù)到原來指標(biāo)，顯然所得結(jié)果不能反映真實情況。土樣取樣、凍土試樣是否固結(jié)、是否達(dá)到固結(jié)度就是關(guān)鍵了。 Ground freezing method is a some kind of anagraph to highrisk problems, therefor the above each procedure must be inspected and confirmed repeatedly in order to realize safety and reliability by monitoring and controlling in time, elaborately constructing and consultant managing strictly. The main points for tests of artificial frozen soil mechanical properties ? 礦山凍結(jié)鑿井中凍土試驗 Frozen soil mechanical property tests for frozen shaft lining ? 市政工程中地層凍結(jié)凍土試驗 Frozen soil mechanical property tests for municipal frozen engineering 上述兩個方面對凍土物理力學(xué)指標(biāo)的要求是不完全相同的。 Uniaxial pressive, tensile and shear strength (cohesion, friction angle), triaxial strength, deformation modulus and poisson ratio (influenced by temperature, water content, unfrozen water content, particle diameter, pore ratio, loading, and loaded time, etc) 2. 地層凍結(jié)法關(guān)鍵要素 (cont.) The key elements for GFM ? 設(shè)計要素 The key factors of design 首先是建立凍土結(jié)構(gòu)受力模型（純凍土結(jié)構(gòu)、和其它結(jié)構(gòu)共同承載、作為其它結(jié)構(gòu)承載的封水等） First step is to chose a frozen structure bearing model (pure frozen soil structure, or other structure jointed with frozen soil, or as water shutoff (frozen soil) for other structure) 其次是在所選結(jié)構(gòu)模型下全面考量全過程可能影響凍土強度、凍土結(jié)構(gòu)本身可能影響周邊環(huán)境或者影響維護結(jié)構(gòu)本身穩(wěn)定和安全的可能性 Second is to prehensively consider the possibility of affecting the permafrost strength in the chosen froze