【正文】 top, set to connect all the top of the pile of reinforced concrete platform. Cap is piles and columns or piers contact part. The root cap, even ten piles are linked with the formation of the pile foundation. Cap for high pile cap generally above the ground or 11 water. High rise pile cap having a free length, the surrounding supporting body to withstand horizontal load. Pile stress situation is extremely unfavorable. Pile internal force and displacement under the action of extremely unfavorable. Pile internal force and displacement under the action of external force than the same level of low pile cap to be big, the stability is poor because of low pile cap. High rise pile cap is generally used for port, wharf, marine engineering and bridge engineering. Low pile cap is generally used in industrial and civil buildings. Pile head generally into platform meters, and a reinforced anchor into the cap. Platform to build on the columns or piers, forming a plete power transmission system. In recent years due to the large diameter bored pile, pile rigidity, strength is big, so high pile in bridge foundation construction has been widely used. 12 全站儀在公路導(dǎo)線和中線測量中的應(yīng)用 摘 要 介紹全站儀在公路導(dǎo)線和中線測量等方面的應(yīng)用技巧，提出全站儀使用中應(yīng)注意的事項(xiàng)。 承臺(tái)指的是為承受、分布由墩身傳遞的荷載，在基樁頂部設(shè)置的聯(lián)結(jié)各樁頂?shù)匿摻罨炷疗脚_(tái)。 樁的靜載試驗(yàn)表明，鉆孔灌注樁的端承力僅占其極限荷載的 15%~35%，側(cè)阻與端阻的發(fā)揮存在不同步現(xiàn)象。采用沖擊式或 沖抓式鉆機(jī)施工時(shí)，附近土層因受到震動(dòng)而影響鄰孔的穩(wěn)固。施工順 序： (1) 施工準(zhǔn)備 施工準(zhǔn)備包括：選擇鉆機(jī)、鉆具、場地布置等。據(jù)統(tǒng)計(jì)，我國鉆（沖）孔樁最大樁徑已達(dá)到 4000mm，最大樁深已達(dá) 104m，兒鋼管樁最大樁徑為 1200mm，最大樁深為 83m，預(yù)應(yīng)力混凝土管樁最大樁徑為 1300mm，最大樁深為 40m。鉆機(jī)位置的偏差不大于 2cm。在終孔檢查完全符合設(shè)計(jì)要求時(shí)，應(yīng)立即進(jìn)行孔底清理，避免隔時(shí)過長以致泥漿沉淀，引起鉆孔坍塌。 研究表明，樁底虛土的存在，不僅影響端阻的發(fā)揮，也是測摩阻力受到損失。高樁承臺(tái)由于具有一段自由長度，其周圍無支撐體共同承受水平外力。 （ 4） 儀器操作人員配置及后視人員的作用 一般用全站儀配合公路導(dǎo)線測量一共需要 5~6人，其中前視位置 3~4人，儀器操作員 1人，后視 1人。一般情況下，導(dǎo)線測量中測點(diǎn)的高程值只作參考，而不能用作水準(zhǔn)測量。 結(jié)束語 全站儀在我國出現(xiàn)只是近幾年的事，大面積的普及應(yīng)用才剛剛開始，但它給我們帶來的方便已經(jīng)是非常顯著了。這樣做的好處是：在不影響測量精度而得到山上點(diǎn)高程的同時(shí)，避免了水準(zhǔn)儀上山頭容易引起水準(zhǔn)點(diǎn)之間不閉合的發(fā)生。角返回了，使得全天的工作都成了無用功。 when the hole wall is not easy to collapse, not more than 20cm. For the post, in water or shoot the breeze, sediment thickness less than 5cm. Hole cleaning method is to use different and flexible application of drilling rig. Usually you can use normal circulation rotary drilling rig, reverse circulation rotary machine vacuum suction machine and slay pumping cylinder hole cleaning. The mud suction machine hole cleaning, required equipment, convenient operation, hole cleaning is thorough, but unstable in the soil should be used cautiously. Its principle is to use pressor generates high pressure air into a suction dredge pipeline will mud blowing. (7) pouring underwater concrete After finishing hole, can be prefabricated reinforcement cage banging vertically into the hole, positioning to be fixed, and then using a perfusion catheter concrete, pouring concrete don’t interrupt, or prone to the phenomenon of broken pile. Effect of bored pile bearing performance factors In the construction process, construction machinery, due to geological effects, often caused by pile soil ( weak layers ), the thickness of ~, thick and up to 1m. Especially in soft soil with mud, drilling, hole bottom sediment is inevitable。先灌漿法是在鉆孔樁成孔后至灌注混凝土前進(jìn)行灌漿，即將噴頭鐵管放入孔底插入虛土，噴射水泥漿 ，使樁底虛土與水泥混合，最后再灌注樁身混凝土。所有這些都影響了鉆孔灌注樁承載力的發(fā)揮。在施工中要注意不斷添加泥漿和抽渣（沖擊式用），還要隨時(shí)檢查成孔是否有偏斜現(xiàn)象。該施工法的過程是：平整場地 → 泥漿制備 → 埋設(shè)護(hù)筒 → 鋪設(shè)工作平臺(tái) → 安裝鉆機(jī)并定位 → 鉆進(jìn)成孔 → 清孔并檢查成孔質(zhì)量 → 下放鋼筋籠 → 灌注水下混凝土 → 拔出護(hù)筒 → 檢查質(zhì)量。 隨著我國社會(huì)主義建設(shè)事業(yè)的迅速發(fā)展，伴隨著高層建筑，大跨度橋梁的興起，對樁基礎(chǔ)的承載力有了更高的要求。對準(zhǔn)樁位后，永枕木墊平鉆機(jī)橫梁，并在塔頂對稱于鉆機(jī)軸線上拉上纜風(fēng)繩。對于摩擦樁當(dāng)孔壁容易坍塌時(shí)，要求在 灌注水下混凝土前沉渣厚度不大于 30cm；當(dāng)孔壁不易坍塌時(shí)，不大于 20cm。樁周軟弱夾層的存在，使得樁體與土體之間的摩擦性質(zhì)發(fā)生改變，對于以樁土之間通過摩擦傳遞荷載來講，是非常不利的?；鶚兜氖芰η闆r極為不利。后視人員可讓全站儀記錄更多的點(diǎn)，對后期中線測量和路線設(shè)計(jì)可13 以起到非常大的作用。 14 全站儀在中線測量中的應(yīng)用 （ 1） 架站位置的選擇 盡量選擇那些地勢較高、通視條件好、可以看到更多中 線上點(diǎn)位的位置。在全站儀的使用過程中，都會(huì)有自己的心得體會(huì)、經(jīng)驗(yàn)技巧，如果 每一個(gè)使用者都能將自己的經(jīng)驗(yàn)奉獻(xiàn)出來，對我們大家來說都將是一筆不小的財(cái)富。我們的做法是：在山腳下選一 個(gè)比較固定的參考點(diǎn)，用全站儀讀出該點(diǎn)的 Z軸高程，隨后用全站儀在放山頭上這些中線點(diǎn)的時(shí)候，順便測出這些點(diǎn)的Z軸高程，可以算出這些點(diǎn)相對于山腳下參考點(diǎn)的高差，這樣用水準(zhǔn)儀測出該參考點(diǎn)的高程后，加上這些高差，便得到山頭下中線點(diǎn)的高程。在省道豫 48 線西峽境的導(dǎo)線測量中，由于初次使用坐標(biāo)法，儀器操作員將架站點(diǎn)和后視點(diǎn)的坐標(biāo)輸反了，結(jié)果在電腦上展圖時(shí)才發(fā)現(xiàn)路線在這個(gè)位置折了 180176。 slurry is too thick will weaken bit impact function, reduce drilling speed. (5) drilling The borehole is a key working procedure, in construction must strictly according to the operating requirements, in order to ensure drilling quality, attention must be given to the hole quality, must be opposite for this good midline and verticality, and pressed well casing. Must pay attention in the construction are continuously added and pumping the slurry slag ( impact type ), but also at any time to check whether there is deviation phenomenon into hole. Using the impulse or clamshell type drilling machine construction, soil due to vibration and impact near the adjacent hole stability. So the drilled hole should be timely cleaning hole, decentralization and pouring underwater concrete reinforcing cage. Drill order should also be practical to plan, should not only guarantee a pile hole construction does not affect the last pile hole drill, and the moving distance of not too far and mutual interference. (6) the hole cleaning The drilling depth, diameter, location and shape of hole is directly related to the quality of pile and pile body black. Therefore, in addition to drilling process close observation 9 supervision, to meet the design requirements in drilling hole depth, with deep, hole pore shape, pore size and other inspections. In the end hole inspection in full pliance with the design requirements, shall immediately proceed to bottom hole cleaning, avoid it too long that mud settling, caused by borehole collapse. For fiction pile when the hole wall is easy to collapse, in underwater concrete perfusion before the sediment thickness of not more than 30cm。 （ 4）灌漿技術(shù)：灌漿法可分為先灌漿法。特別是松軟地層中鉆孔，用泥漿護(hù)壁，孔底沉渣更不4 可避免；即使經(jīng)過特別仔細(xì)清孔，清孔后至灌注混凝土前，仍會(huì)沉淀一些沉渣，且在程控過程中，都普遍存在對孔壁和孔底土層的擾動(dòng)。 （ 5）鉆孔 鉆孔是一道關(guān)鍵工序，在施工中必須嚴(yán)格按照操作要求進(jìn)行，才能保證成孔質(zhì)量，首先要注