隧道出口施工方案

溪洛渡水电站对外交通专用公路

凉水一号隧道工程

凉水一号隧道出口开挖支护施工方案

中铁隧道集团有限公司 2006年12月2日

目 录

一、目前的状况 ······································································································ - 3 -

1.1、边坡施工状况 ············································································································································· - 3 - 1.2、隧道已施工状况 ········································································································································ - 3 - 1.3、隧道出口施工设备 ···································································································································· - 3 - 1.4、隧道出口边坡监测 ···································································································································· - 3 -

二、隧道开挖工法··································································································· - 4 - 三、隧道施工过程中的注意事项 ············································································· - 4 -

3.1、边坡施工 ····················································································································································· - 4 - 3.2、隧道施工 ····················································································································································· - 4 - 3.3、监控量测 ····················································································································································· - 5 -

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一、目前的状况

1.1、边坡施工状况

隧道出口段已开挖边坡为石灰岩及亚粘土碎石土地层。隧道洞口位置下部揭露的地层为石灰岩地层，灰白、青灰色，钙质胶结，中薄层构造，受构造影响严重，岩体节理裂隙发育，有不良地质顺层现象；隧道洞口上部为碎石土，棕褐色，碎石成份以石灰岩为主砂岩次之，其余为为亚粘土充填。目前以完成锚索穿孔7孔，已注浆，未施作锚墩，未张拉。

洞身上部覆盖碎石土（Q4d17），厚度大于10m，黄褐色－灰黄色，碎石成份以石灰岩为主，其余为亚粘土填充，中密－密实，稍湿。原设计为格构梁加预应力锚索。现未施作。

1.2、隧道已施工状况

LsT1隧道出口洞身范围内主要分布石灰岩（），灰白、青灰色，钙质胶结，

细晶结构，中－薄层构造，夹薄层状泥灰岩，岩质坚硬，但受构造影响严重，岩体节理裂隙发育，且有不良地质顺层现象。

目前已施作2榀拱墙格栅。第3、4榀格栅隧道左侧已架立，还未施作系统锚杆（停电）。

1.3、隧道出口施工设备

隧道出口开挖无相应的开挖台架，钻孔靠搭设钢管架进行。

1.4、隧道出口边坡监测

由于隧道开挖在边坡未完成的情况下进行（设计要求将坡面锚索施作完

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成后才能进洞），为此在洞身上方设监测点9个，共三横排三竖排。拟采用三维坐标进行监测，监测设备采用TCR702全站仪进行。坡面每天监测1次，及时分析坡面变化情况。

二、隧道开挖工法

隧道开挖分左右两部分进行，先进行隧道右侧的开挖及支护，再进行隧道右侧的开挖及支护。具体的步骤见附图。

三、隧道施工过程中的注意事项

3.1、边坡施工

1、每次施工上排架前，领工或工班长需要仔细检查排架的稳定状况，对需要加固的地方及时进行加固，避免隧道爆破振动对高排架造成的松动，影响排架稳定。

2、隧道上方已施工的锚索尽早进行锚墩施工，为尽早进行锚索张拉作准备。

3、边坡锚索施工宜加快进度进行，为及早封闭边坡创造有利条件。

3.2、隧道施工

1、由于隧道为变截面施工，隧道跨度在不断的变化，而钢架为预先加工的成品，这要求在架立钢架的过程中不得随意挪动钢架的位置，不能因为局部的欠挖或不好立而改变钢架的位置。

2、由于隧道较扁平，格栅架立架立后受力效果不好，需要加强系统锚

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杆的施作，系统锚杆的长度及数量必须按设计要求施作，不得随便减少。 3、隧道开挖进尺严格控制，应严格遵循短进尺，弱爆破，确保施工安全。不得大爆破。

4、在开挖过程中线路左侧的临时边坡不得产生大的超挖。 5、仰拱应及时施作，不得延误。

3.3、监控量测

1、隧道施工测量需要勤放样。常复核。 2、隧道需要施作临时净空收敛的测量工作。 3、隧道需要进行拱顶下沉监控。 4、隧道出口边坡需要进行坡面位移监测。

5、所有监测的数据及时处理，及时反馈，以指导施工。

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