Study on the Change of Earthquake Ground Motion Parameters for Different Classification Sites of Ocean Areas
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摘要: 基于海域场地分类标准,选取南海海域实测钻孔作为计算模型,同时人工构造部分钻孔计算模型,对126条不同特性地震动输入下5种类别场地计算模型开展土层反应分析计算,分析不同地震动输入下不同海域场地峰值加速度和特征周期变化规律。结果表明,场地类别和地震动输入强度显著影响峰值加速度放大系数和特征周期,场地土越软,地震动输入强度越大,峰值加速度放大系数越小,特征周期越大。根据研究结果给出不同地震动输入下不同海域场地峰值加速度放大系数、特征周期变化范围,为海域场地工程抗震设防和编制海域地震动参数区划图提供参考。Abstract: Based on site classification standards for ocean areas, the boreholes in the South Sea of China are selected as calculation model for site response. Due to the insufficiency of ocean geological data, some boreholes are also constructed for site response. By using 126 ground motions with different characteristics, site response was conducted for 5 kinds of classification sites. The change of peak acceleration and characteristic period under different input motions for different site classifications is analysized. Results show that site classifications and peak acceleration of input ground motion greatly influenced the amplification coefficients of peak acceleration and characteristic periods. The conclusion are as follows: amplification coefficient becomes smaller and characteristic period becomes longer when the site goes softer and input motion goes stronger. The variation range of amplification coefficients and characteristic periods under different input motions and site classifications are concluded. The results can be inferred to anti-seismic design of ocean engineering structures and to the earthquake ground motion parameters zonation of ocean areas.
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表 1 海域场地分类标准
Table 1. Site classification standards for ocean areas
项目 沉积年代/厚度 Q3 Q4/H≤40 m Q4/40<H≤60 m Q4/60<H≤100 m Q4/H>100 m 40 m等效剪切波速Vse/m·s−1 Vse>500 350<Vse≤500 290<Vse≤350 240<Vse≤290 190<Vse≤240 Vse<190 场地类别 Ⅰ0 Ⅰ1 Ⅱ Ⅲ Ⅳ Ⅴ 表 2 Ⅴ类场地计算模型
Table 2. Calculation model for V classification site
土层序号 土层描述 非线性特性土样编号 土层深度/m 层厚/m 波速Vs/(m·s−1) 密度/(kg·m−3) 1 非常软的粉质黏土至砂质黏土 S-18A 0.0~2.0 2.0 100 1 880 2 松散细砂 S-6A 2.0~5.2 3.2 136 1 892 3 密实的细砂至中砂 S-11A 5.2~12.7 7.5 170 1 898 4 稍硬的粉质黏土和粉土质砂互层 S-15B 12.7~14.8 2.1 196 2 000 5 稍硬至硬的粉质黏土 S-18A 14.8~17.8 3.0 210 1 904 6 密实的细砂 S-26B 17.8~28.0 10.2 220 1 900 7 密实至非常密实的细砂 S-26B 28.0~44.0 16.0 225 2 000 8 硬至非常硬的粉质黏土 S-41A 44.0~51.4 7.4 395 2 000 9 中密至密实的粉土质细砂 S-41A 51.4~60.6 9.2 298 1 970 10 密实至非常密实的细砂至中砂 S-53 60.6~72.5 11.9 416 1 920 11 硬至非常硬的粉质黏土 S-55C 72.5~76.0 3.5 468 2 045 12 密实的细砂至中砂 S-57 76.0~87.3 11.3 389 1 908 13 非常硬粉质黏土和砂质粉砂互层 S-60C 87.3~89.4 2.1 401 1 955 14 砂质粉土与粉质黏土迭层 S-61B 89.4~93.1 3.7 427 1 950 15 密实的细砂至粗砂 S-57 93.1~98.5 5.4 478 2054 16 硬至非常硬的粉质黏土和密实的粉砂、粉质细砂叠层 S-66A 98.5~114.6 16.1 449 1 900 17 非常密实的细砂至粗砂 S-57 114.6~120.2 5.6 490 2 000 18 计算基底 — 120.2 — 500 2 000 表 3 Ⅰ1类场地钻孔计算模型
Table 3. Calculation model for Ⅰ1 classification site
土层序号 土层描述 非线性特性土样编号 土层深度/m 层厚/m 波速Vs/m·s−1 密度/kg·m−3 1 密实的细砂 S-26B 0.0~5.0 5.0 240 1 900 2 密实至非常密实的细砂 S-26B 5.0~10.0 5.0 273 2 000 3 中密至密实的粉土质细砂 S-41A 10.0~15.0 5.0 298 1 970 4 硬至非常硬的粉质黏土 S-41A 15.0~20.0 5.0 395 2 000 5 密实至非常密实的细砂至中砂 S-53 20.0~25.0 5.0 416 1 920 6 硬至非常硬的粉质黏土 S-55C 25.0~30.0 5.0 468 2 045 7 密实的细砂至粗砂 S-57 30.0~35.0 5.0 478 2054 8 非常密实的细砂至粗砂 S-57 35.0~40.0 5.0 490 2 000 9 计算基底 — 40.0 — 500 2 000 4a Ⅰ1类场地峰值加速度放大系数
4a. Amplification coefficient of peak acceleration for Ⅰ1 classification site
特征周期/s 峰值加速度/gal 50 100 150 样本1 样本2 样本3 样本1 样本2 样本3 样本1 样本2 样本3 0.25 1.39 1.55 1.33 1.35 1.43 1.25 1.24 1.34 1.26 0.30 1.39 1.32 1.43 1.26 1.30 1.37 1.33 1.27 1.30 0.35 1.58 1.44 1.35 1.37 1.44 1.41 1.27 1.27 1.27 0.40 1.47 1.62 1.41 1.33 1.39 1.28 1.35 1.24 1.35 0.45 1.36 1.31 1.39 1.33 1.35 1.49 1.35 1.43 1.33 0.55 1.45 1.45 1.36 1.26 1.35 1.32 1.48 1.32 1.37 0.65 1.34 1.44 1.44 1.32 1.48 1.40 1.35 1.35 1.35 4b Ⅰ1类场地峰值加速度放大系数
4b. Amplification coefficient of peak acceleration for Ⅰ1 classification site
特征周期/s 峰值加速度/gal 200 300 400 样本1 样本2 样本3 样本1 样本2 样本3 样本1 样本2 样本3 0.25 1.38 1.27 1.14 1.29 1.21 1.13 1.16 1.34 1.18 0.30 1.36 1.37 1.29 1.20 1.12 1.29 1.26 1.09 1.32 0.35 1.39 1.17 1.35 1.32 1.34 1.21 1.34 1.19 1.18 0.40 1.33 1.29 1.37 1.27 1.33 1.27 1.33 1.13 1.34 0.45 1.35 1.41 1.32 1.24 1.47 1.31 1.32 1.27 1.11 0.55 1.41 1.35 1.33 1.32 1.21 1.27 1.26 1.30 1.29 0.65 1.34 1.29 1.21 1.27 1.27 1.29 1.27 1.26 1.26 表 5 不同类别场地峰值加速度放大系数
Table 5. Statistical charts of peak acceleration amplification coefficient for different classification sites
场地类别 峰值加速度/gal 50 100 150 200 300 400 Ⅰ1 变化范围 1.31~1.62 1.25~1.49 1.24~1.48 1.14~1.41 1.12~1.47 1.09~1.34 均值 1.42 1.36 1.32 1.32 1.27 1.25 Ⅱ 变化范围 1.22~1.60 1.05~1.35 1.06~1.52 1.06~1.36 1.08~1.34 1.03~1.31 均值 1.38 1.23 1.20 1.23 1.19 1.18 Ⅲ 变化范围 1.12~1.49 1.10~1.43 0.98~1.30 0.91~1.24 0.79~1.18 0.74~1.04 均值 1.26 1.21 1.13 1.05 0.92 0.91 Ⅳ 变化范围 1.05~1.41 0.99~1.47 0.87~1.25 0.84~1.31 0.65~1.03 0.53~1.10 均值 1.25 1.19 1.07 1.03 0.85 0.82 Ⅴ 变化范围 1.05~1.37 0.97~1.47 0.81~1.20 0.80~1.11 0.61~1.07 0.5~1.03 均值 1.24 1.18 1.07 0.98 0.75 0.70 表 6 Ⅰ1类场地反应谱特征周期
Table 6. Characteristic period of acceleration response spectrum for Ⅰ1 classification site
特征周期/s 峰值加速度/gal 50 100 150 200 300 400 0.25 0.30 0.30 0.30 0.30 0.35 0.35 0.30 0.35 0.35 0.35 0.35 0.40 0.40 0.35 0.40 0.40 0.40 0.40 0.45 0.45 0.40 0.45 0.45 0.45 0.45 0.45 0.50 0.45 0.50 0.50 0.50 0.50 0.50 0.55 0.55 0.60 0.60 0.60 0.60 0.60 0.65 0.65 0.70 0.70 0.70 0.70 0.70 0.75 表 7 不同类别场地地表反应谱特征周期
Table 7. Characteristic period of acceleration response spectrum for different classification sites
输入地震动特征周期/s 场地类别 Ⅰ1 Ⅱ Ⅲ Ⅳ Ⅴ 0.25 变化范围 0.30~0.35 0.30~0.35 0.35~0.40 0.45~0.55 0.40~0.90 均值 0.32 0.34 0.37 0.51 0.63 0.30 变化范围 0.35~0.40 0.35~0.45 0.40~0.50 0.50~0.60 0.50~1.00 均值 0.37 0.41 0.47 0.57 0.74 0.35 变化范围 0.40~0.45 0.40~0.50 0.45~0.60 0.55~0.70 0.55~1.10 均值 0.42 0.46 0.52 0.62 0.79 0.40 变化范围 0.45~0.50 0.45~0.55 0.50~0.65 0.65~0.75 0.65~1.20 均值 0.46 0.51 0.61 0.72 0.85 0.45 变化范围 0.50~0.55 0.50~0.60 0.55~0.75 0.70~0.90 0.70~1.30 均值 0.51 0.55 0.64 0.81 0.88 0.55 变化范围 0.60~0.65 0.60~0.70 0.65~0.90 0.80~0.90 0.80~1.50 均值 0.61 0.65 0.74 0.86 0.95 0.65 变化范围 0.70~0.75 0.70~0.80 0.75~1.00 0.90~1.10 0.90~1.80 均值 0.71 0.75 0.86 0.98 1.2 -
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