Advanced tangent modulus method and its application to calculation of foundation settlement
-
摘要: 切线模量法方法简单、参数少,易于工程应用,研究表明在计算常规尺寸的基础时具有较好的精度,而对于筏板这样的大尺寸基础时,当计算深度较深时,存在计算沉降偏大的问题。为此提出了考虑初始切线模量沿深度增大的高级切线模量法,通过与实际工程案例和小应变有限元数值计算方法结果比较,高级切线模量法能更符合实际,进一步发展完善了切线模量法。Abstract: The tangent modulus method proposed by YANG Guang-hua is simple, with few parameters and easy for engineering application. The researches have shown that it has better accuracy when calculating the foundations with conventional dimensions, but for the large-sized foundations such as rafts, the calculated settlement is too large. For this reason, an advanced tangent modulus method considering the increase of the initial tangent modulus extension depth is proposed. The comparison with the actual engineering case and the calculated results by the finite element method of the small-strain hardening soil model shows that the advanced tangent modulus method can be more realistic. This further develops and improves the tangent modulus method.
-
-
表 1 有限元小应变硬化土模型参数取值
Table 1 Mechanical parameter of soil for small strain hardened model
土层 γ/(kN·m-3) νur c/kPa φ/(°) Knc0 pref/kPa m Gref0/MPa Erefoed/MPa Eref50/MPa Erefur/MPa γ0.7 伦敦黏土 18.44 0.2 2 24 0.59 100 0.5 40 6.73 8 16 9.68×10-4 表 2 莫尔-库仑模型参数取值
Table 2 Mechanical parameters for Mohr Coulomb model
土层 γ/(kN·m-3) ν c/kPa φ/(°) E/MPa 伦敦黏土 18.44 0.3 2 24 7.3 表 3 线弹性模型参数取值
Table 3 Mechanical parameters for linear elastic model
土层 γ/(kN·m-3) ν E/MPa 伦敦黏土 18.44 0.3 7.3 表 4 1 m×1 m压板Et0随深度变化情况
Table 4 Variation of Et0 of 1 m×1 m plate with buried depth
H/m K0 Et0/MPa a b 0 18.25 14.61 0.0548 0.0056 1.0 28.82 23.08 0.0347 0.0022 1.5 32.15 25.75 0.0311 0.0020 2.0 39.84 31.90 0.0251 0.0018 2.5 46.73 37.42 0.0214 0.0014 3.0 48.08 38.50 0.0208 0.0013 4.0 54.95 44.00 0.0182 0.0013 5.0 61.73 49.43 0.0162 0.0009 6.0 64.52 51.66 0.0155 0.0008 7.0 69.93 56.00 0.0143 0.0007 表 5 土的基本力学参数
Table 5 Mechanical parameters of soil
土体名称 γ/(kN·m-3) c/kPa φ/(°) e Es1-2/MPa E0/MPa 粉质黏土 18.5 18.3 19.5 1.15 7.5 14 淤泥质黏土 17.6 7.5 5.8 1.20 3 4.1 砂质粉土 18.3 10 20 1 7.4 14 表 6 莫尔-库仑模型参数取值
Table 6 Mechanical parameters for Mohr Coulomb model
土层 γ/(kN·m-3) ν c/kPa φ/(°) E/MPa 粉质黏土 18.5 0.3 18.3 19.5 14 淤泥质黏土 17.6 0.3 7.5 5.8 4.1 砂质粉土 18.3 0.3 10 20 14 表 7 线弹性模型参数取值
Table 7 Mechanical parameters for linear elastic model
土层 γ/(kN·m-3) ν E/MPa 粉质黏土 18.5 0.3 14 淤泥质黏土 17.6 0.3 4.1 砂质粉土 18.3 0.3 14 表 8 小应变硬化土模型参数取值
Table 8 Mechanical parameters of soil for small-strain hardening model
土层 γ/(kN·m-3) νur c/kPa ϕ/(°) Knc0 pref/kPa m Gref0/MPa Erefoed/MPa Eref50/MPa Erefur/MPa γ0.7 粉质黏土 18.50 0.2 18.3 19.5 0.6662 100 0.8 63.0 14 14.0 42.0 2×10-4 淤泥质黏土 17.60 0.2 7.5 5.8 0.8989 100 0.8 18.1 4.1 4.1 12.3 2×10-4 砂质粉土 18.30 0.2 10.0 20.0 0.6580 100 0.5 63.0 14 14.0 42.0 2×10-4 表 9 土的基本力学参数
Table 9 Mechanical parameters of soil
土体名称 γ/(kN·m-3) c/kPa φ/(°) E0/MPa 细砂 18.5 0 37 44.4 粉砂① 18.5 0 38 48.7 粉质黏土 18.5 25 22 27.0 粉砂② 18.5 0 39 67.3 白垩纪砂岩 18.5 150 38 250.0 表 10 莫尔-库仑模型参数取值
Table 10 Parameters for Mohr Coulomb model
土层 γ/(kN·m-3) ν c/kPa φ/(°) E/MPa 细砂 18.5 0.3 0 37 44.4 粉砂① 18.5 0.3 0 38 48.7 粉质黏土 18.5 0.3 25 22 27.0 粉砂② 18.5 0.3 0 39 67.3 白垩纪砂岩 18.5 0.3 150 38 250.0 表 11 线弹性模型参数取值
Table 11 Parameters for linear elastic model
土层 γ/(kN·m-3) ν E/MPa 细砂 18.5 0.3 44.4 粉砂① 18.5 0.3 48.7 粉质黏土 18.5 0.3 27.0 粉砂② 18.5 0.3 67.3 白垩纪砂岩 18.5 0.3 250.0 表 12 小应变硬化土模型参数取值
Table 12 Parameters of soil for small-strain hardening model
土层 γ/(kN·m-3) νur c/kPa φ/(°) Knc0 pref/kPa m Gref0/MPa Erefoed/MPa Eref50/MPa Erefur/MPa γ0.7 细砂 18.5 0.2 0 37 0.398 100 0.5 199.8 44.4 44.4 133.2 2×10-4 粉砂① 18.5 0.2 0 38 0.384 100 0.5 438.3 48.7 48.7 146.1 2×10-4 粉质黏土 18.5 0.2 25 22 0.625 100 0.8 121.5 27.7 27.7 81.0 2×10-4 粉砂② 18.5 0.2 0 39 0.371 100 0.5 302.8 67.3 67.3 201.9 2×10-4 白垩纪砂岩 18.5 0.2 150 38 0.384 100 0.5 1125.0 250 250 750.0 2×10-4 -
[1] 王海波, 徐明, 宋二祥. 基于硬化土模型的小应变本构模型研究[J]. 岩土力学, 2011, 32(1): 39–43, 136. doi: 10.3969/j.issn.1000-7598.2011.01.007 WANG Hai-bo, XU Ming, SONG Er-xiang. A small strain constitutive model based on hardening soil model[J]. Rock and Soil Mechanics, 2011, 32(1): 39–43, 136. (in Chinese) doi: 10.3969/j.issn.1000-7598.2011.01.007
[2] 建筑地基基础设计规范: GB 50007—2011[S]. 2012. Code for Design of Building Foundation: GB 50007—2011[S]. 2012. (in Chinese)
[3] 杨光华. 地基非线性沉降计算的原状土切线模量法[J]. 岩土工程学报, 2006, 28(11): 1927–1931. doi: 10.3321/j.issn:1000-4548.2006.11.002 YANG Guang-hua. Nonlinear settlement computation of the soil foundation with the undisturbed soil tangent modulus method[J]. Chinese Journal of Geotechnical Engineering, 2006, 28(11): 1927–1931. (in Chinese) doi: 10.3321/j.issn:1000-4548.2006.11.002
[4] 杨光华, 王俊辉. 地基非线性沉降计算原状土切线模量法的推广和应用[J]. 岩土力学, 2011, 32(增刊1): 33–37. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2011S1007.htm YANG Guang-hua, WANG Jun-hui. Application of undisturbed soil tangent modulus method for computing nonlinear settlement of soil foundation[J]. Rock and Soil Mechanics, 2011, 32(S1): 33–37. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2011S1007.htm
[5] 杨光华. 根据经验地基承载力反算土的强度和变形参数[J]. 广东水利水电, 2002(1): 3–6. https://www.cnki.com.cn/Article/CJFDTOTAL-GDSD200201000.htm YANG Guang-hua. According to the experience of foundation bearing capacity to inverse the strength and deformation parameters of soil[J]. Guangdong Water Resources and Hydropower, 2002(1): 3–6. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GDSD200201000.htm
[6] 杨光华. 深基坑支护结构的实用计算方法及其应用[M]. 北京: 地质出版社, 2004. YANG Guang-hua. Practical Calculation Method of Retaining Structures for Deep Excavations and Its Application[M]. Beijing: Geological Publishing House, 2004. (in Chinese)
[7] DUNCAN J M, CHANG C Y. Nonlinear analysis of stress and strain in soils[J]. Journal of the Soil Mechanics and Foundations Division, 1970, 96(5): 1629–1653. doi: 10.1061/JSFEAQ.0001458
[8] 赵同顺, 周波. 大型油罐地基变形特性的研究[J]. 岩石力学与工程学报, 2004, 23(6): 1037–1043. doi: 10.3321/j.issn:1000-6915.2004.06.028 ZHAO Tong-shun, ZHOU Bo. Deformation behaviors of soft foundation under large oil tank[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(6): 1037–1043. (in Chinese) doi: 10.3321/j.issn:1000-6915.2004.06.028
[9] 赵同顺. 5×104 m3大型油罐岩土工程实录[C]// 第五届全国岩土工程实录交流会岩土工程实录集, 2000, 南京. ZHAO Tong-shun. Geotechnical engineering record of 5×104m3 large oil tank[C]// The 5th National Geotechnical Engineering Record Exchange Conference, 2000, Nanjing. (in Chinese)
[10] 舒武堂, 李国胜, 蒋涛. 武汉地区淤泥质软土、黏性土的压缩模量与变形模量的相关关系[J]. 岩土工程界, 2004, 7(7): 29–30. https://www.cnki.com.cn/Article/CJFDTOTAL-YSJS200407011.htm SHU Wu-tang, LI Guo-sheng, JIANG Tao. The correlativity between the compression model and elastic model for silt and clay in Wuhan[J]. Geotechnical Engineering World, 2004, 7(7): 29–30. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSJS200407011.htm
[11] C M PLANT G W. The settlement performance of a raft supporting a 27-storey hotel on estuarine deposits in Durban[J]. Civil Engineering = Siviele Ingenieurswese, 1990, 32(6).
[12] 建筑地基基础设计规范: DBJ15—31—2016[S]. 2016. Design Code for Building Foundation: DBJ15—31— 2016[S]. 2016. (in Chinese)