[{"data":1,"prerenderedAt":61},["ShallowReactive",2],{"q-105170-arch_construction-43":3},{"question":4,"neighbors":26,"sameNumber":45,"prev":34,"next":37},{"id":5,"classKey":6,"session":7,"year":8,"subject":9,"number":10,"groupStem":11,"ownStem":12,"stem":12,"options":13,"answer":18,"answerKind":20,"answerS":11,"answerNote":11,"images":21,"explanation":22,"withheld":11,"deepChars":23,"freq":24,"indexable":25},"arch-105170-801-0103-043","architect","105170",105,"建築構造與施工",43,null,"反循環基樁較不適用於下列何種地層？",{"A":14,"B":15,"C":16,"D":17},"黏土","砂土","礫石","砂質黏土",[19],"C","single",[],"本題考點：反循環基樁（反循環鑽掘工法）的施工原理，以及它對地層顆粒大小與透水性的限制。\n【正解理由】反循環基樁屬於場鑄的鑽掘式基樁：以旋轉鑽頭在孔內切削土壤，孔內灌滿清水或穩定液，並使孔內水位高於地下水位，靠這股靜水壓差撐住孔壁；切削下來的土渣隨循環水由鑽桿中心被抽吸上來，送到沉澱池分離後，水再回流孔內。因為土渣必須「從鑽桿內部被吸上來」，孔壁又必須「靠孔內水頭撐住」，這個工法天生有兩個弱點：其一，粒徑大於鑽桿內徑的礫石、卵石吸不上來，會卡在鑽頭或堵塞管路，鑽頭也難以切削堅硬的大顆粒；其二，礫石層孔隙大、透水性高，孔內的水會大量逸失到地層中，維持不住孔內水頭，孔壁容易崩塌。四個選項中只有礫石同時踩中這兩個弱點，故選 C。\n【逐項排除】\n(A) 黏土：黏土顆粒細、透水性低，鑽頭切削後的土渣能隨循環水由鑽桿吸出，孔內水頭不易流失，孔壁自立性也較好，是反循環工法適用的地層，不符題目所問的「較不適用」。\n(B) 砂土：砂土沒有凝聚力，孔壁穩定全靠孔內水頭與穩定液，但砂粒細小，可隨循環水順利吸出；只要孔內水位維持在地下水位以上，就能形成撐住孔壁的壓差，因此砂土正是反循環工法的典型適用地層，不符題目所問。砂土施工要注意的是孔底沉渣要清除乾淨，那屬於施工品質要求，不代表工法不適用。\n(C) 礫石：大顆粒礫石無法通過鑽桿吸出，鑽頭切削也困難；礫石層透水性高，孔內水大量流失，無法維持撐住孔壁的靜水壓差而容易坍孔。排渣與護壁兩項機制同時失效，屬於反循環基樁較不適用的地層，符合題目所問，為正解。相對地，以鋼套管撐住孔壁、以抓斗直接抓出大顆粒的全套管工法，較能應付礫石與卵礫石層。\n(D) 砂質黏土：砂與黏土混合，顆粒仍細，透水性介於砂土與黏土之間，切屑能隨循環水吸出，孔壁也能靠孔內水頭穩定，屬適用地層，不符題目所問。\n【記憶點】反循環＝鑽桿吸渣＋孔內水頭護壁，怕「吸不上來的大顆粒」與「留不住水的高透水層」，兩者都指向礫石。",677,1,true,[27,30,33,36,39,42],{"number":28,"session":7,"stem":29},40,"現場的施工圖（shop drawing）應由何單位準備？",{"number":31,"session":7,"stem":32},41,"下列敘述有關建築物設有固定座椅席位者，其輪椅觀眾席位數量，何者錯誤？",{"number":34,"session":7,"stem":35},42,"建築工程地下室採用逆打工法，最主要目的為何？",{"number":37,"session":7,"stem":38},44,"下列何者與基盤調查之目的無關？",{"number":40,"session":7,"stem":41},45,"下列何種工程災害是在軟弱黏土層實施基礎開挖施工時，最可能發生的現象？",{"number":43,"session":7,"stem":44},46,"在合歡山寒冷地區建一棟二層樓遊客中心，外牆採清水磚造，下列圖示砌磚灰縫何者正確？",[46,49,52,55,58],{"number":10,"session":47,"stem":48},"114180","構造物於大地定位時，所放樣的軸線交點樁，於土方整地、開挖基礎或地下室時，導致這些樁體…",{"number":10,"session":50,"stem":51},"113190","發現直立之女兒牆體有斜紋龜裂滲水，此一場地條件最不適宜選用下列防水材料作處理？",{"number":10,"session":53,"stem":54},"112190","有關廠製金屬三明治板外牆，下列敘述何者錯誤？",{"number":10,"session":56,"stem":57},"111180","有關 RC 構造耐震補強工法之敘述，下列何者錯誤？",{"number":10,"session":59,"stem":60},"110180","關於地基調查的相關內容，下列何者錯誤？",1791863214678]