某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì)連續(xù)梁橋方案畢業(yè)論文.doc

某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì)連續(xù)某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì)連續(xù) 梁橋方案畢業(yè)論文梁橋方案畢業(yè)論文 目錄目錄 目目 錄錄 1 前前 言言 3 第一章第一章 工程概述工程概述 4 1 1 工程概況 4 1 2 設(shè)計(jì)條件 4 1 2 1 工程地質(zhì)和地震 4 1 2 2 氣象和水文 4 1 3 設(shè)計(jì)標(biāo)準(zhǔn)和設(shè)計(jì)規(guī)范及建筑材料 4 1 3 1 設(shè)計(jì)規(guī)范 4 1 3 2 主要技術(shù)標(biāo)準(zhǔn) 4 1 3 3 主要建筑材料 5 1 4 橋型總體布置 6 1 4 1 橋跨布置 6 1 5 橋梁構(gòu)造 6 第二章第二章 主橋結(jié)構(gòu)計(jì)算分析主橋結(jié)構(gòu)計(jì)算分析 7 2 1 計(jì)算模型和施工階段劃分 7 2 2 懸臂節(jié)段劃分及單元?jiǎng)澐?7 2 3 主要計(jì)算荷載如下 8 第三章第三章 恒載內(nèi)力計(jì)算及變形分析恒載內(nèi)力計(jì)算及變形分析 9 3 1 毛截面特性計(jì)算 9 3 2 恒載集度計(jì)算 11 3 2 1 一期恒載集度 11 3 2 2 二期恒載集度 12 3 3 時(shí)程內(nèi)力計(jì)算 12 3 3 1 梁段懸臂施工內(nèi)力 12 3 3 2 邊跨梁體合攏內(nèi)力 14 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 1 3 3 3 中跨梁體合攏內(nèi)力 17 3 4 恒載內(nèi)力結(jié)果 20 3 4 1 一期恒載內(nèi)力 20 3 4 2 二期恒載內(nèi)力 22 3 4 3 總恒載內(nèi)力 27 第四章第四章 活載內(nèi)力計(jì)算及內(nèi)力組合活載內(nèi)力計(jì)算及內(nèi)力組合 30 4 1 汽車和人群活載內(nèi)力計(jì)算 30 4 2 溫度次內(nèi)力計(jì)算 34 4 3 支座沉降次內(nèi)力計(jì)算 37 4 4 荷載組合及內(nèi)力包絡(luò)圖 38 4 4 1 組合方法 38 4 4 2 計(jì)算結(jié)果 40 4 4 3 內(nèi)力包絡(luò)圖 56 第五章第五章 預(yù)應(yīng)力鋼束估算與布置預(yù)應(yīng)力鋼束估算與布置 58 5 1 鋼束估算 58 5 1 1 估算原理 58 5 1 2 鋼束估算結(jié)果 59 5 2 橫向預(yù)應(yīng)力布置 61 5 3 豎向預(yù)應(yīng)力布置 60 5 4 預(yù)應(yīng)力損失及有效預(yù)應(yīng)力計(jì)算 60 5 4 1 預(yù)應(yīng)力損失及有效預(yù)應(yīng)力計(jì)算方法 60 5 5 主梁次內(nèi)力計(jì)算 64 5 5 1 預(yù)應(yīng)力產(chǎn)生的二次內(nèi)力 64 第六章第六章 主要控制截面應(yīng)力及承載能力驗(yàn)算主要控制截面應(yīng)力及承載能力驗(yàn)算 66 6 1 強(qiáng)度驗(yàn)算原理 66 6 1 1 承載能力極限狀態(tài)驗(yàn)算 66 6 1 2 使用階段正截面應(yīng)力驗(yàn)算 71 第七章第七章 變形計(jì)算與預(yù)拱度設(shè)置及錨下局部應(yīng)力驗(yàn)算變形計(jì)算與預(yù)拱度設(shè)置及錨下局部應(yīng)力驗(yàn)算 73 7 1 撓度計(jì)算 73 7 1 1 變形計(jì)算 驗(yàn)算及預(yù)拱度設(shè)置 73 7 1 2 變形計(jì)算結(jié)果 74 7 2 變形驗(yàn)算及預(yù)拱度設(shè)置 75 外文文獻(xiàn) 77 參考文獻(xiàn)參考文獻(xiàn) 87 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 2 前前 言言 畢業(yè)設(shè)計(jì)是高等工科院校本科培養(yǎng)計(jì)劃中最后一個(gè)重要的教學(xué)環(huán)節(jié) 目的 是使學(xué)生在學(xué)完培養(yǎng)計(jì)劃所規(guī)定的基礎(chǔ)課 技術(shù)基礎(chǔ)課及各類必修和選修專業(yè) 課程之后 通過畢業(yè)設(shè)計(jì)這一環(huán)節(jié) 較為集中和專一地培養(yǎng)學(xué)生綜合運(yùn)用所學(xué) 的基礎(chǔ)理論 基本知識(shí)和基本技能 分析和解決實(shí)際問題的能力 和以往的理 論教學(xué)不同 畢業(yè)設(shè)計(jì)是要學(xué)生在教師的指導(dǎo)下 獨(dú)立地 系統(tǒng)地完成一個(gè)工 程設(shè)計(jì) 以期能掌握一個(gè)工程設(shè)計(jì)的全過程 在鞏固已學(xué)課程的基礎(chǔ)上 學(xué)會(huì) 考慮問題 分析問題和解決問題 并可以繼續(xù)學(xué)習(xí)到一些新的專業(yè)知識(shí) 有所 創(chuàng)新 畢業(yè)設(shè)計(jì)是培養(yǎng)學(xué)生獨(dú)立工作的一種良好途徑和方法 它的實(shí)踐性和綜 合性是其它教學(xué)環(huán)節(jié)所不能替代的 懸臂澆筑預(yù)應(yīng)力混凝土連續(xù)梁橋作為無支架施工有利于通航河流建橋 深 山峽谷建橋和城市立交建橋等 懸臂施工的受力特點(diǎn)接近于成橋后的結(jié)構(gòu)受力 懸臂施工法在我國(guó)已有成熟的經(jīng)驗(yàn) 懸臂澆筑預(yù)應(yīng)力混凝土梁橋得到飛躍發(fā)展 并成為當(dāng)代橋梁建筑中最基本的橋型之一 通過對(duì)麻車大橋主橋的初步設(shè)計(jì) 使我進(jìn)一步加深了對(duì)橋梁設(shè)計(jì)與施工理論知識(shí)的理解 對(duì)懸臂施工連續(xù)箱梁有 了初步了解 是對(duì)大學(xué)四年所學(xué)知識(shí)的總結(jié) 本設(shè)計(jì)中用到了結(jié)構(gòu)力學(xué) 材料力學(xué) 結(jié)構(gòu)設(shè)計(jì)原理 橋梁工程等學(xué)科的 諸多知識(shí) 并且我從圖書館借閱了大量參考書籍力求將設(shè)計(jì)做到規(guī)范 合理 清楚 雖然該橋結(jié)構(gòu)不算復(fù)雜 但整個(gè)結(jié)構(gòu)設(shè)計(jì)計(jì)算量大 數(shù)據(jù)眾多 難度較 大 當(dāng)然 也正是由此 我得到切實(shí)的鍛煉和提高 它使我這四年所學(xué)的專業(yè) 知識(shí)更加系統(tǒng)化 具體化 對(duì)我以后從事橋梁方面的工作具有很好的指導(dǎo)意義 通過設(shè)計(jì)讓我了解連續(xù)梁橋的主要特點(diǎn)和施工方法 了解和掌握橋梁設(shè)計(jì) 的全過程 通過老師的指導(dǎo) 培養(yǎng)學(xué)生獨(dú)自完成橋梁工程的設(shè)計(jì)計(jì)算 鍛煉學(xué) 生綜合運(yùn)用專業(yè)基礎(chǔ)知識(shí) 專業(yè)知識(shí)的能力 培養(yǎng)學(xué)生的創(chuàng)新能力 在設(shè)計(jì)過程中 我得到了李其林老師 路橋其他老師的悉心指導(dǎo) 及其楊 龍同學(xué)的耐心幫助 在此一并表示衷心的感謝 由與本人的水平有限 在設(shè)計(jì)中一定存在著缺點(diǎn)和錯(cuò)誤 懇請(qǐng)老師和同學(xué) 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 3 們批評(píng)指正 第一章第一章 工程概述工程概述 1 1 工程概況工程概況 本項(xiàng)目位于長(zhǎng)沙市寧鄉(xiāng)縣 是寧鄉(xiāng)縣交通圈的重要組成部分 該特大橋的 建設(shè)將為寧鄉(xiāng)縣經(jīng)濟(jì)圈的發(fā)展壯大提供便捷的交通支撐 同時(shí)也保證居民過江 安全 1 2 設(shè)計(jì)條件設(shè)計(jì)條件 1 2 1 工程地質(zhì)和地震工程地質(zhì)和地震 地質(zhì) 橋位區(qū)內(nèi)地質(zhì)構(gòu)造較為簡(jiǎn)單 巖層為單斜構(gòu)造 無斷裂構(gòu)造 橋位 周邊地勢(shì)較為平坦 發(fā)生災(zāi)害地質(zhì)的可能性較小 區(qū)內(nèi)不良地質(zhì)現(xiàn)象主要為淤 泥質(zhì)土和表層軟土 埋藏深度一般為 0 3 1 2m 砂卵石層中局部含泥量較高 且多位于稍密狀態(tài) 膠結(jié)性較差 地震 據(jù)區(qū)域資料 本區(qū)在燕山期及以前的地質(zhì)年代里 構(gòu)造運(yùn)動(dòng)強(qiáng)烈 到喜山期基本結(jié)束了大規(guī)模的斷裂和褶裂 地殼運(yùn)動(dòng)主要表現(xiàn)為升降運(yùn)動(dòng) 深 大斷裂逐漸趨于穩(wěn)定 從上更新世以來 本區(qū)地殼垂直上升速率小于 0 17mm 年 地殼基本處于穩(wěn)定狀態(tài) 本區(qū)近代地震的特點(diǎn)是強(qiáng)度弱 震級(jí)小 頻度低 1 2 2 氣象和水文氣象和水文 項(xiàng)目所在區(qū)域地處亞熱帶季風(fēng)氣候區(qū) 氣候溫暖 濕潤(rùn)多雨 從季節(jié)變化 看 冬季在冷高壓控制下 氣候干冷 但河道不封凍 夏季在副熱帶控制下 天氣睛熱 氣溫 1 月份平均氣溫 6 7 月份平均 32 年平均無霜期在 265 天左 右 年均總降雨量 1600 毫米 6 7 月的梅雨季節(jié) 該季節(jié)降雨強(qiáng)度大 持續(xù)時(shí) 間長(zhǎng) 往往造成江河洪澇災(zāi)害 常風(fēng)向東北風(fēng) 14 多年平均風(fēng)速 1 6M s 多年平均暴日數(shù) 36 天 多年平均霧日 18 9 天 1 3 設(shè)計(jì)標(biāo)準(zhǔn)和設(shè)計(jì)規(guī)范及建筑材料設(shè)計(jì)標(biāo)準(zhǔn)和設(shè)計(jì)規(guī)范及建筑材料 1 3 1 設(shè)計(jì)規(guī)范設(shè)計(jì)規(guī)范 1 JTG D60 2004 公路橋涵設(shè)計(jì)通用規(guī)范 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 4 2 JTG D62 2004 公路鋼筋混凝土及預(yù)應(yīng)力混凝土橋涵設(shè)計(jì)規(guī)范 3 JTG D63 2007 公路橋涵地基與基礎(chǔ)設(shè)計(jì)規(guī)范 4 姚玲森 橋梁工程 人民交通出版社 2008 5 鄒毅松 王銀輝 橋梁計(jì)算示例叢書 連續(xù)梁橋 人民交通出版社 2009 6 陳忠延 土木工程專業(yè)畢業(yè)設(shè)計(jì)指南 橋梁工程分冊(cè) 中國(guó)水利水電 出版社 2000 7 范立礎(chǔ) 預(yù)應(yīng)力混凝土連續(xù)梁橋 人民交通出版社 1999 1 3 2 主要技術(shù)標(biāo)準(zhǔn)主要技術(shù)標(biāo)準(zhǔn) 1 設(shè)計(jì)荷載 汽車荷載等級(jí) 公路 I 級(jí) 汽車荷載 3 05KN m 人群荷載 標(biāo)準(zhǔn)按 JTG D60 2004 4 3 5 取值 本橋主跨 110m 人群荷載應(yīng)取 2 9KN m 由于橋位處在城鎮(zhèn)郊區(qū)人群密集地區(qū) 故標(biāo)準(zhǔn)提高 15 2 橋梁寬度 橋梁總寬 12m 其中 行車道 4 3 75m 非機(jī)動(dòng)車道 2 1 925m 防撞護(hù)欄 2 0 5m 3 橋面橫坡 2 4 設(shè)計(jì)洪水頻率 1 100 5 設(shè)計(jì)最高通航水位 27 6m 通航凈空 凈寬 102m 凈高 7m 本橋主 橋 110m 主跨為雙向通航孔 60m 邊跨禁止通航 6 船舶撞擊作用 按四級(jí)內(nèi)河航道船舶噸級(jí)為 500t 順橋向撞擊作用 為 450KN 橫橋向撞擊作用為 550KN 7 橋梁護(hù)欄 主橋防撞護(hù)欄采用 SB 級(jí) 1 3 3 主要建筑材料主要建筑材料 混凝土 對(duì)于簡(jiǎn)支轉(zhuǎn)連續(xù)施工 預(yù)制梁及其現(xiàn)澆接縫 封錨 墩頂現(xiàn)澆連 續(xù)段 橋面現(xiàn)澆層均采用 C50 混凝土 基樁采用 C25 其余構(gòu)件采用 C30 對(duì)于 懸臂施工 主梁采用 C50 混凝土 墩身 承臺(tái)采用 C30 混凝土 基樁采用 C25 預(yù)應(yīng)力鋼絞線 采用 公路鋼筋混凝土及預(yù)應(yīng)力混凝土橋涵設(shè)計(jì)規(guī)范 JTG D62 2004 中 d 15 2mm 的鋼絞線 公稱面積為 140mm2 標(biāo)準(zhǔn)強(qiáng)度 fpk 1860MPa 彈性模量 Ep 1 95 105MPa 普通鋼筋 R235 HRB335 鋼筋標(biāo)準(zhǔn)應(yīng)符合 GB13013 1991 和 GB1499 1998 的規(guī)定 凡鋼筋直徑 12mm 者 均采用 HRB335 熱軋帶肋鋼筋 凡鋼筋直徑 Mt Io 構(gòu)件全截面的換算截面慣性矩 Io1 構(gòu)件截面開裂后的換算截面慣性矩 2 長(zhǎng)期變形計(jì)算 由于預(yù)應(yīng)力 構(gòu)件自重及二期恒載是持續(xù)作用的 而已求出使用荷載下變 形只是由這些荷載引起的初始短期彈性變形 在長(zhǎng)期持續(xù)荷載作用下 混凝土 徐變將使變形增大 考慮混凝土徐變對(duì)預(yù)加力 自重及二期恒載變形影響后 長(zhǎng)期變形的計(jì)算應(yīng)用下列公式 7 1 3 1 1 2211 tftfff ggp 式中 以施工預(yù)應(yīng)力和構(gòu)件自重作用時(shí)刻為砼加載齡期的徐變系數(shù) 1 t 以二期恒載作用時(shí)刻為砼加載齡期的徐變系數(shù) 2 t 在上式中考慮預(yù)加力和結(jié)構(gòu)自重同時(shí)起作用 即預(yù)應(yīng)力施加后構(gòu)件已拱起 脫模 長(zhǎng)期最終變形可取 t 的徐變系數(shù)計(jì)算求得 本設(shè)計(jì)中 2 2 1 t 2 t 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 74 7 1 2 變形計(jì)算結(jié)果變形計(jì)算結(jié)果 以跨中截面為例計(jì)算主梁的短期變形 長(zhǎng)期變形的計(jì)算略 1 邊跨變形驗(yàn)算 邊跨跨中 12 號(hào)單元 汽車荷載作用產(chǎn)生的撓度為 其中換算截面的慣性矩為 I0 79 0756 1012mm 5 1780 106 1100002 48 0 95 3 5 104 19762 109 0 2 95 0 IE ML f h 汽 3 33mm 6000 600 100mm 滿足要求 2 中跨變形驗(yàn)算 中跨跨中 36 號(hào)單元 汽車荷載作用撓度 其中換算截面的慣性矩為 I0 27 4313 1012mm 5 1760 106 1100002 48 0 95 3 45 104 13563 1012 0 2 95 0 IE ML f h 汽 7 26mm 110000 600 183mm 滿足要求 7 2 變形驗(yàn)算及預(yù)拱度設(shè)置變形驗(yàn)算及預(yù)拱度設(shè)置 1 邊孔變形驗(yàn)算及預(yù)拱度設(shè)置 變形驗(yàn)算 由上面可知汽車荷載作用下最大撓度為 0 333cm 發(fā)生在跨中 而撓度限 值為 L 600 6000 600 10cm 即有 0 333 cm 10cm 汽max f 2 中孔變形驗(yàn)算及預(yù)拱度設(shè)置 變形驗(yàn)算 由上可知汽車荷載作用下最大撓度為 0 726cm 發(fā)生在跨中 而撓度限值 為 L 600 110000 600 18 3cm 即有 0 726cm 18 3 cm 汽max f 預(yù)拱度設(shè)置 因在恒載及預(yù)應(yīng)力引起主梁變形計(jì)算中已計(jì)入徐變影響 則 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 75 汽 ffff ygg 21max 采用 L 4 截面處的永存預(yù)加力矩作為全橋平均預(yù)加力計(jì)算值 即在使用階 段的預(yù)加力矩為 1129 4 38800 350 15337 3 kNm yyyy eAM 則主梁反拱度 跨中截面 計(jì)算為 dx IE MM f L h xy y 0 0 95 0 0 2 95 0 48 5 IE LM h y 5 15337 3 106 1100002 48 0 95 3 45 104 13563 109 60 05 3 由主梁自重和二期恒載作用引起的撓度 5 1100002 6350 16700 g f 106 48 0 95 3 45 104 13563 109 79 66mm 4 使用荷載作用下跨中變形f 汽 ffff ygg 21max 79 66 60 05 7 26 26 87mm L 1600 110000 1600 68 8mm 根據(jù) 公路橋規(guī) 規(guī)定 當(dāng)結(jié)構(gòu)重力和汽車荷載 不計(jì)沖擊力 作用下產(chǎn) 生的最大豎向撓度不超過計(jì)算跨徑的時(shí) 可不設(shè)預(yù)拱度 由上計(jì)算可知本 1 1600 設(shè)計(jì)不需設(shè)置預(yù)拱度 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 76 外文文獻(xiàn)外文文獻(xiàn) BURIEDBURIED DEEPDEEP ININ HIGHHIGH PRESSUREPRESSURE ININ THETHE SUPPORTINGSUPPORTING TECHNOLOGYTECHNOLOGY OFOF SOFTSOFT ROCKROCK ENVIRONMENTENVIRONMENT 1 Introduction Along with the increasing of mining depth and affection of high stress the mine pressure in deep rock roadway increases largely And the common Bolting Shotcrete method cannot match this kind of situation obviously It is very difficult to mine safely The reasons 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 77 about failure of supporting and its countermeasures are researched according to the analysis of one case in this paper 2 General situation of one case A roadway locates in between the 7 1 and 8 3 mining layer with length 800m depth 1050m elevation 一 920m and rock sandstone The east part of this roadway locates in one comparatively wide synclinal The structure stress is high about 33 40Mpa The cross section of the roadway is vertical wall and semicircle arch using 30mm concrete as temporary supporting and Bolting Shotcrete as permanence With the support failure yielding support U25 are used to support The parameters are presented as follows Bolt bottom grouted resin bolt 1800mm length interval 800mm 800mm Metal mesh 5000mm 1050mm 8 wire net grid 100mm 100mm Concrete common Portland cement strength of the concrete C150 100 200mm thick as showing in Fig 1 Using this support method the roadway was excavated 120m long After 2 months great deformation appeared the width of roadway sides decreased from 4100mm to 3600 3800mm and the floor heaved500mm The Bolting Shotcrete structure slipped and some anchors broke 3 Analyses According to the research the reasons leading to failure of the roadway can be described as follows 1 The thickness of self support layer of surrounding rock was too small In common supporting method using bottom grouted resin bolt the self support layer was about 0 6m far smaller than that of overall length of anchors The surrounding rock pressure was hard to be resisted and it was some kinds of wasting on bolt 2 The initial support stiffness was too large After excavation since the redistribution of surrounding rock stress and deformation 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 78 the pressure coming froth surrounding rock was great And the larger of the stiffness of supporting structure the larger pressure loading on it see as Fig 2 There is an intimate relation between the stiffness of supporting structure and surrounding rock pressure The stiffness of the above support is too large to adapt to the characteristics of fast speed and large deformation in initial excavation which lead to the roadway destroy because of discontinuous deformation of the support and the surroundings 3 The binding ability of surrounding rock surface is low Under the affection of high stress and structure stress superfluous deformation of supporting structure appeared in comparative weak area firstly Then the rock relaxed and failed and formed fracture zone The development of fracture zone led to the failure of self support layer In deep high stress soft rock roadway when using common Bolting Shotcrete method the strength of shotcrete structure was relatively low and its binding ability was not high enough to stop local failure and the development of fracture zone Then the surrounding rock failed 4 The method using one time Bolting Shotcrete as permanent Fig 2 Rock support interaction supporting structure did not match the rule appearing in deep high stress soft rock roadway High pressure and continuous deformation were the base characteristics of deep roadway after excavation and it was hard to support one off After the failure of one time Bolting shotcrete supporting using U steel to support led to the waste of supporting material and effective space of roadway 5 Unenclosed supporting structure was not suitable for deep high stress soft rock roadway In deep high stress soft rock roadway the deformation of surrounding rock was relatively great The floor 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 79 without treatment heaved largely when using unclosed supporting method When the floor ripping more relaxation of sidewall appeared then the root of sidewall failed and then the whole roadway failed 6 The Bolting Shotcrete structure was unreasonable In the case when using Bolting Shotcrete method the Bolting and Netting were installed firstly then shot concrete Therefore the wire mesh was located in the bottom of the concrete and the function of its tensile resistance and the compressive resistance of concrete were limited 7 The shape of cross section must be suitable for the high stress situation In deep roadway since the side pressure was relatively large the deformation of sidewall was great and the stability of the top was also affected 4 Countermeasures According to above analysis the common supporting method cannot resolve the supporting problems in deep high stress soft rock roadway And corresponding countermeasures must be adopted accordingly 1 The binding ability of surrounding rock surface must be strengthened to prevent the fracture zone from developing direct to the inner parts For example to strengthen the stiffness and strength of the mesh or to install bolting beam on local weak part can satisfy the request 2 The secondary supporting method can be taken accordingly In deep high stress soft rock roadway the initial deformation was great with quick deformation speed So the supporting structure trust be relatively flexible In the initial period large deformation can be allowed to release the energy with precondition of no failure of roadway But excessive deformation must be controlled Therefore in the later period sufficient strength and stiffness were necessary 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 80 In the secondary support period to strengthen the strength of bolting and mesh such as increasing the length of anchors or installing abutting beam and steel band can be useful The best time to execute the secondary support was when the deformation reached the max and become stable 3 Using heavy wall can increase the support results One method was to use equal strength whorl steel anchor with full column cement grouted bolting to increase the thickness of self support layer of surrounding rock Another method was to use cable anchor Cable anchor can reach deep stable rock because of its great length and load pressure about 200KN on the rock and the bad deformation can be limited So the thickness of self support layer was enlarged The third method was to change the supporting structure Installing incline anchors on the root of roadway or forming the floor as anti arch then installing anchor beam to form an enclosed and integrated structure 4 Decreasing the failure zone increasing the surrounding rock strength and self support ability was a good method One method was to use smooth surface blasting which can decrease the surrounding rock shake and control circular cracking to maintain the integrity Second point was to maintain a smooth and even surface of roadway to avoid stress concentration The third was to use expansible material to fill the anchor hole 5 Applications According to the above analysis a new design for the 920 roadway presented above was done A horseshoe arch was adopted because of swelling rock and serious floor heave The follow supporting technique was adopted Firstly using the common Bolting Shotcrete to support for about 25 days based on the measurement of mine pressure 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 81 Then the secondary support can be executed to form united support with sprouting bolting with sprouting and bolting netting with sprouting method And at the end of the secondary support cable anchor beam can be used as permanent supporting Supporting parameters are Anchor d518mm equal strength whorl steel anchor with full column cement grouted bolting 1800mm in length 1000mm 1000mm in interval interlaced arrangement in twice bolting and 500mm 1000mm in final spacing Wire mesh 5000mm 1050mm 8 wire netting grid with 100mm 100mm Concrete common Portland cement strength of the concrete 0150 120mm thick 90mm in the first time 30mm in the second Supporting processes 1 Excavating 2 Temporary supporting with 30mm concrete 3 Installing bolts 4 Sprouting concrete to 80 of the designed thickness 120mm 5 Executing the secondary support after 25 days with bolt mesh 6 Sprouting concrete to the designed thickness 7 Installing anchor cable and anchor beam By using above method and technique the supporting situation was good Only some little schistose fell off and the displacement of the top and sidewall were limited under 146mm No floor heaving appeared 6 Conclusion 1 The common supporting method cannot resolve the questions of deep high stress soft rock roadway and corresponding countermeasures must be used according to the real situation of mine pressure and reason 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 82 of failure 2 Some methods must be useful such as strengthening the binding ability of the surrounding rock surface to avoid more development of fracture zone executing the secondary bolting netting with sprouting support to reform the structure and improve bearing situation increasing the strength and stiffness of secondary supporting structure to control the deformation effectively 3 Using equal strength whorl steel anchor with full column cement grouted bolting can improve the bearing situation and increase the thickness self support layer 4 As for deep high stress soft rock roadway enclosed supporting structure was the best selection At the same time installing incline anchors on the root of roadway or forming the floor as anti arch with anchor beam to form a enclosed and integrated supporting structure was useful method 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 83 在深埋高壓力軟巖環(huán)境中的支護(hù)技術(shù)在深埋高壓力軟巖環(huán)境中的支護(hù)技術(shù) 1 引言 隨煤礦深度的增加和高壓力的影響 在深埋巖層中巷道的煤礦的礦壓力大大增 加了 普通錨噴支護(hù)的方法在這種情形下明顯不被采用 這樣煤礦的安全便成 為一大難題 主要原因在于支護(hù)手段的失效 本論文通過一個(gè)工程事例來研究 其中的對(duì)策 2 在一般情形下的事例 有一條巷道位于和煤層之間 長(zhǎng)為 800 米 埋深為 1050 米 開挖深度為 920 米 巖性為砂巖 在巷道東邊探明有一個(gè)相對(duì)較寬的向斜 這種結(jié)構(gòu)所能承受 的力很大 大約為 巷道的斷面形式為直墻半圓拱形 采用厚的噴射混凝土作 為臨時(shí)支護(hù)和錨噴作為永久支護(hù) 被用于支護(hù)的 U25 型鋼產(chǎn)生屈服而使支護(hù)系 統(tǒng)破壞 永久支護(hù)的概述如下 錨桿 端部灌漿樹脂錨桿 長(zhǎng)為 1800mm 間距為 800mm 鋼筋網(wǎng) 鋼絲網(wǎng) 網(wǎng)間距為 100mm 混凝土 普通硅酸鹽水泥 水泥強(qiáng)度等級(jí)為 C150 厚度為 100 200mm 用此種支護(hù)方法進(jìn)行支護(hù) 在巷道被開挖 120 米長(zhǎng)時(shí) 兩個(gè)月后巷道才出現(xiàn)很 大的變形 此時(shí)巷道的寬度從減少到了 并且底板隆起近 錨噴支護(hù)結(jié)構(gòu)產(chǎn)生 滑移并且一些錨桿被破壞 3 分析 根據(jù)研究 導(dǎo)致巷道支護(hù)坡壞的原因被述敘如下 1 圍巖自承的支護(hù)層厚度太小 在普通的支護(hù)方法中 采用端部灌漿樹脂錨 桿 自承層的厚度大約為 0 6 米 它比起整個(gè)錨桿的長(zhǎng)度來太小 圍巖的壓力 很難被抵擋住而且還有一些抗力則被浪費(fèi)在錨桿上了 2 初始剛性支護(hù)力太大 開挖后 產(chǎn)生圍巖壓力和變形的重分布 因而來自 圍巖的壓力是很大的 剛性支護(hù)結(jié)構(gòu)的抗力要大一些 荷載的壓力也會(huì)大一些 在圍巖支護(hù)結(jié)構(gòu)和圍巖壓力之間最終有一定的關(guān)系 在開挖初期 為了適應(yīng)圍 巖變形大而快的特性上部支護(hù)結(jié)構(gòu)的剛度也要大一些 因?yàn)椴贿B續(xù)的支護(hù)形式 和圍巖變形將能導(dǎo)致巷道破壞 某線壟井特大橋主橋上部結(jié)構(gòu)設(shè)計(jì) 60 2 110 60 連續(xù)梁橋方案 84 3 圍巖表面的粘結(jié)能力太差 在高壓力和結(jié)構(gòu)應(yīng)力的影響下 支護(hù)結(jié)構(gòu)的變 形首先出現(xiàn)在比較松軟的區(qū)域 此時(shí)巖石的松弛和缺陷形成為破碎帶 破碎帶 的發(fā)展導(dǎo)致自承層的破壞 在深埋高壓的軟巖巷道中 當(dāng)采用普通的錨噴支護(hù) 時(shí) 混凝土結(jié)構(gòu)的強(qiáng)度相對(duì)較低 斷裂面的發(fā)展與局部破壞使混凝土的粘結(jié)能 力不會(huì)很強(qiáng) 此時(shí)圍巖則已經(jīng)破壞 4 用錨噴支護(hù)作為一次永久性支護(hù)結(jié)構(gòu)的方法 在深埋高壓的軟巖巷道中沒 有被采用過 高壓和連續(xù)變形是深埋巷道開挖后基本特征 因而很難一次性支 護(hù) 一次錨噴支護(hù)破壞后 采用 U 型鋼支護(hù)將會(huì)導(dǎo)致支護(hù)材料和巷道有效空間 的浪費(fèi) 5 不封閉的支護(hù)結(jié)構(gòu)不適用于深埋高壓的軟巖巷道 在深埋高壓的軟巖巷道 中 圍巖的相對(duì)變形很大 在底板沒有進(jìn)行處理時(shí) 采用不封閉的支護(hù)方法進(jìn) 行支護(hù)將產(chǎn)生很大隆起 當(dāng)?shù)装彘_裂后 更多的松弛則出現(xiàn)在邊墻上 此時(shí)邊 墻的根部被破壞 因而使整個(gè)巷道也被破壞 6 不合理的錨噴支護(hù) 在一些情況下當(dāng)采用錨噴的方法進(jìn)行支護(hù)時(shí) 首先是 安裝錨桿和錨網(wǎng) 之后再噴射混凝土 因此 錨噴網(wǎng)被安置在混凝土的底部 它的作用是抗拉 而混凝土則被限制而抗壓 7 巷道的斷面形式必須與高壓力的情形相適應(yīng) 在深埋巷道中 自從側(cè)向壓 力相對(duì)變大后 邊墻的變形也會(huì)相對(duì)增大 頂部的穩(wěn)定性也會(huì)受到影響 4 解決方案 根據(jù)上面的分析 在深埋高壓的軟巖巷道中 普通的支護(hù)方法不能解決其支護(hù) 問題 信息法施