四川大学水利水电学院峨眉山工程地质报告

水利工程地质实习报告

目录

1 工程任务及工区自然地理概况·····················1

1.1 自然地理位置····································1 1.2 自然地理概况·····································1

2工程区地形地貌、地质概况························2

2.1 坝区地形地貌·····································2 2.2 坝区地层岩性·····································2

2.21峨眉山总体地层岩性·······································2 2．22龙门硐坝址区地层岩性·····································4

2．3坝区地质构造·····································4

2．31峨眉山断层···············································4 2．32牛背山断层···············································4 2．33观心庵断层···············································5 2．34回龙山断层···············································5 2．35峨眉山背斜···············································5 2．36牛背山背斜···············································5 2．37桂花场向斜···············································5

3 工程部位岩体结构特征概况·······················6

3.1 主要结构面成因及类型·····························6 3.2 主要结构面产状、性质简述··························6 3.3 坝址区岩体结构类型·······························7

4专题分析······································7

4.1 坝基的稳定性分析·································7 4.2 坝址区边坡稳定分析·······························7

4．21坝址边坡稳定地质条件分析·································7 4.22拟建坝区岸坡稳定工程措施及建议···························8

4.3 坝区水文地质条件分析····························9 4.4 坝区渗漏问题分析································10

4．41坝区渗漏问题地质条件分析································10 4．42坝区渗漏防治措施及建议··································10

5 工区建筑材料情况及施工场条件调查··············11

5．1坝址区建筑材料概况······························11 5．2坝址区坝型选择··································12

6 最佳坝型选择··································14 7 结论和建议····································14

7．1结论············································14 7．2建议············································15

拟建龙门硐水库坝型论证

1工程任务及工程区自然地理概况

1.1 自然地理位置

峨眉山位于四川盆地南隅，地处四川省峨眉山市，地处长江上游，屹立于大渡河与青衣江之间，在峨眉山市西南7公里，东距乐山市37公里，是著名的佛教名山和旅游胜地，有“峨眉天下秀”之称，是一个集佛教文化与自然风光为一体的国家级山岳型风景名胜区。

1.2 自然地理概况

峨眉山最大相对高差达2600m。按其高程与高差，大峨山应属于强烈切割中山；龙门硐一代属于中等切割中山；山麓地带的龙马山、红珠山等则是具有残丘特征的低山，峨眉平原以西南高、东北低为特点。3098.8m的高海拔使得山区内热带、亚热带、寒带三种气候带兼备，且雨量充沛；山区内年均温按海拔分布大致为3.1℃～17℃；土壤中有中、酸、碱性土壤，非常适合各类植物的生长，植物种类繁多复杂，全山森林面积约667k㎡，森林覆盖率为87%。区内水系属大渡河水系。受西南高、东北低的地形控制，河流流向均自西南向东北，并在归入大渡河后继续东流至乐山注入岷江。峨眉山地区公路交通较为发达，成乐高速连接成都至乐山，还有成昆铁路在东南侧南北穿越，往来十分方便。

眉山青衣江峨眉峨眉山峨眉河临江河河江乐山岷N 区内水系属大渡河水系，受西南高、东北低的地形控制，河流流向均自西向东，并在归入大渡河后继续东流至乐山并注入岷江。 大

峨边渡犍为0102030 km

图一 峨眉山地区水系图

2工程区地形地貌、地质概况

2.1坝区地形地貌

本次建坝工程位于峨眉山山麓黄湾乡龙门硐口，紧靠牛背山断层，地处东翼倒转断层上，坝址为北纬29度34分44秒，东经103度25分06秒，海拔540米。中国地质史上中生代末期的燕山运动，奠定了峨眉山地质构造的轮廓。而新构造期的喜马拉雅运动，及其伴随的青藏高原的抬升，造就了峨眉山。峨眉山由于山顶上是一大片古生代喷出的玄武岩，其下岩层受到保护而得以保持高度，又因山中内部“瀑流切割强烈”，进而形成了高2000米以上的“峡谷奇峰地形”。实习路线沿途地形因地层之分而多貌并存：如处于石灰岩层中有藏九老洞之类的岩洞地貌；花岗岩及变质岩区，形成了深峡谷地貌；山顶上玄武岩则形成熔岩平台地貌。

图二 坝址卫星图

2.2坝区地层岩性

2.21峨眉山总体地层岩性

峨眉山地区的底层除志留系、泥盆系和石岩系完全缺失外，从前震旦系顶部至第四系地层均有出露，其中除前震旦系和上二叠统下部为岩浆岩外，其余是一套由碳酸盐岩、碎屑岩和泥质岩组成的，总计厚度七千余米的沉积岩。 从清音电站到坝址段，沿途有：峨眉山花岗岩(γ2 )，出露于峨眉山背斜核部的峨眉山玄武岩(P2β)，斜斑玄武岩(具五～六变边形粗大柱状节理)，微晶玄武岩(具细长柱状节理)，杏仁状玄武岩，沉积岩，有除石炭系～中奥陶统外的所有地层。