晚近國內地下機械式掘進工程日增,如引水或山岳隧道、都會捷運、污水下水道等,在台灣山多平地少的地形特徵與複雜多變的地質狀況下施工,或多或少均遭遇到諸多掘削不力之工程困境。 為能總括評估開挖不同尺度(開挖規模)之地下掘進工程,本研究乃嘗試建立適用於不同工法(全斷面隧道開挖、潛盾、管推等工法)、工種(土壓式、泥水式、泥濃式等工法) 及地質(土、礫、岩)材料之推力設計演算,首先依正常施工掘進狀況,對整體切削機盤中各個不同之每一刀頭貫切力進行加總並詳評群刀效應及刀頭磨耗影響;以作為接觸域直線推力之合力,以進行廣義式地下掘進之推力分析模式。再以異況警戒之風險管理概念,設定正常施工推力之上、下限。並與現行既有公式進行比對。綜觀本研究額外考慮之推力影響因子:探討單一刀頭貫切力加總與群刀效應之考量;掘進縱向坡度及地下水造成浮力之影響,並以四種不同工程情況(前方阻抗受主動抑或被動側壓推擠、周側阻抗之機身或管身是否被地質包覆密貼與壓密)作為推力上、下限之評估以作為施工風險指標探討。現場驗証方面,則以桃園機場卵礫石層及砂岩之潛盾施工為例,進行直線段推力比對。 由外業調查分析發現,卵礫石層與風化砂岩總阻抗上、下限值;分別佔正常施工掘進值之(401 %, 37.8 %)與(258.2 %, 31.7 %),進行正規化後之前方阻抗值於卵礫石層與風化砂岩層則各為(13×10^-4 ~ 82×10^-4) 、(0.97 ~ 4.98),而在本研究直線推力計算之卵礫石層刀頭貫切力比率最大可佔總阻抗(F=4773kN)之28%, 說明了岩、礫之接觸場貫切力宜應加入推力計算方為合理。
In recent years, the domestic engineering is increasing on underground tunneling by mechanical cutting, for example tunnel in the mountain, rapid transit system in the city and sewer. The complex geological is usually digging difficulties in Taiwan. The tunneling is studied for include the different dig scale. The paper is establishing different method (tunnel boring machine, shield tunnel and pipe jacking,) , type (earth pressure balance, slurry pressure balance, thick-mud) and geological (soil, gravel and rock) model to calculate thrust. The straight thrust is calculate that is blunt cutter or global Indentation to local Indentation of tunneling machine in normal work. In normal work, the upper bound and lower bound is limited for the unusual situation warned in risk management. In addition to already has the formula to compare, the study is additional assess effect factor:Single cut indent to Doubled-cutters indent, the axial gradient of tunnel, floating power and different working condition (active or passive earth pressure, machine or pipe touch tight or densification by geological gable). The field confirmation is Taoyuan international airport Shield tunnel engineering. By field survey and analysis discovery, total thrust to upper bound and lower bound is normal thrust (401%, 37.8%) and (258.2%, 31.7%) in gravel and sandstone. Normalization value (13×10^-4 ~ 82×10^-4) and (0.97 ~ 4.98) respectively at front resistance in gravel and sandstone. The cutter’s indentation force is possible to account for total thrust (F=4773kN) 28% in the gravel. It explained that finest thrust calculate to consider indentation.