Study on Comprehensive Treatment of Geotechnical Engineering in a Site Area
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摘要: 某项目场地选址于两侧南北走向山脊间的深切“V”字形沟谷中,南、北、东三侧面临突出的岩土问题,即南、北两侧高边坡稳定和东侧山谷洪水治理。三侧岩土问题在时空上呈耦联、递进关系,治理难度较大,在系统阐述三侧岩土问题工程地质特征的基础上制定了防护治理对策。研究及实践表明,精确的工程地质资料是岩土治理的基础,而对治理工程全局概念性的把控又是指导勘察设计的关键,治理设计与治理勘察紧密结合是岩土治理工程的核心要素;选址于山谷的工程防洪是关键问题,需建立通畅的排洪渠道,依据场地重要性等级科学合理制定防洪标准,确定频遇流量;对于小型滑坡治理,优先采取清方处理措施更为合理,对于清方后的耸立的高边坡需进行稳定性分析、评价,确定合理的防护对策,确保整个边坡的安全。Abstract: A site is located in the deep V-shaped valley between the north-south ridges on both sides. It faces stability of high slopes on both sides of the south and north and flood control in the east valley. The geotechnical problems on the three sides are coupled and progressive in time and space, and there are considerable difficulties in treatment. Based on the systematic description of the engineering geological characteristics of the geotechnical problems on the three sides, the protection and treatment countermeasures are formulated. The research and practice show that the accurate engineering geological data is the foundation and premise of geotechnical treatment, and the overall conceptual control of the treatment project is the key to guiding the investigation and design. The close combination of treatment design and treatment investigation is the core element of the success or failure of geotechnical treatment engineering. Flood control of the project located in the valley is a key issue and it is necessary to establish a smooth flood discharge channel, scientifically and reasonably formulate flood control standards according to the importance level of the site, and determine the frequent flow. For the treatment of small-scale landslide, it is more reasonable to give priority to the treatment measures of clearing the earth. For the high slope after clearing the earth, it is still necessary to carry out stability analysis and evaluation, determine reasonable protection measures, and ensure the safety of the whole slope. The contents can provide guidance and reference for similar projects.
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Key words:
- high slope /
- landslide /
- flood /
- engineering geology /
- treatment project
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表 1 参数指标、稳定系数及设计推力表
代表
断面计算
工况稳定
系数c/
kPaφ/
(°)安全
系数出口推力/
(kN·m−1)抗力/
(kN·m−1)设计推力/
(kN·m−1)2-2 天然 1.17 15 25.5 1.3 2650 1600 1050 暴雨 1.15 12 25 1.2 2400 地震 1.12 15 25.5 1.15 2100 3-3 天然 1.16 15 29.5 1.3 3100 3200 暴雨 1.12 12 28.0 1.2 3200 地震 1.11 15 29.5 1.15 2500 4-4 天然 1.15 15 35 1.3 3700 3700 暴雨 1.12 12 34.5 1.2 3500 地震 1.11 15 35 1.15 2800 5-5 天然 1.12 15 28 1.3 2700 3000 暴雨 1.07 12 26.5 1.2 3000 地震 1.06 15 28 1.15 2300 6-6 天然 1.12 15 34 1.3 1600 1700 暴雨 1.07 12 33 1.2 1700 地震 1.06 15 34 1.15 1100 表 2 百年一遇来洪量计算表
设计依据 计算公式 流量/(m3·s−1) 《滑坡防治设计规范》[12] Qp=ΦSpF 19.60 铁一院法推理公式[13] ${Q_{\rm{p}}} = {\left[ {\dfrac{ { {k_1}(1 - {k_2}){k_3} } }{ { {X^2} } } } \right]^{\frac{1}{ {1 - {n'}y} } } }$ 19.51 太原工大数理统计法[14] Qp=2212.8(1+1.04lgT)/(t+10.4)0.83 20.08 城建局图解法[14] Qp=1017(1+1.7lgP)/t0.73 19.99 《公路涵洞设计规范》[15] Qp=0.278(Sp/τn−μ)F 18.60 注:Qp为设计频遇流量,m3/s;Φ为径流系数;Sp为设计降雨强度,mm/h;F为汇水面积,km2;k1为产流因子;k2为汇流因子;k3为造峰因子;X为山坡和主河槽汇流因子;n′为随暴雨衰减指数n而变的指数;y为反映流域汇流特征的指数;t为降雨历时,min;T为汇流时间,min;P为重现期,年;τ为汇流时间,h;n为暴雨递减指数。 表 3 堆积层滑坡整体稳定系数计算表
代表剖面 计算工况 γ/(kN·m–3) c/kPa φ/(°) 稳定系数Fs 13-13 天然 18.6 10 20 1.04 暴雨 20.0 8 19 1.02 地震 18.6 8 19 1.01 14-14 天然 18.6 10 20 1.05 暴雨 20 8 19 1.03 地震 18.6 8 19 1.02 表 4 13-13剖面残留堆积层滑坡稳定系数及推力计算表
代表
剖面计算
工况稳定系数
Fsγ/
(kN·m−3)c/
kPaφ/
(°)安全
系数Fst出口处
推力/
(kN·m−1)设计
推力/
(kN·m−1)13-13 天然 1.04 18.6 10 20 1.3 400 400 暴雨 1.02 20.0 8 19 1.2 280 地震 1.01 18.6 8 19 1.15 258 -
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