天津地区粉质黏土水土压力计算方法研究

杜占磊; 刘晓磊

doi:10.20265/j.cnki.issn.1007-2993.2024-0235

天津地区粉质黏土水土压力计算方法研究

doi: 10.20265/j.cnki.issn.1007-2993.2024-0235

天津市勘察设计院集团有限公司，天津　300191

基金项目: 天津市科技计划项目（15ZXCXSF00070）

详细信息

作者简介:
杜占磊，男，1978年生，大学本科，高级工程师，主要从事岩土工程勘察、基坑设计等方面的工作。E-mail：xiaogoudagou@163.com

中图分类号: P432
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- 文章访问数: 19
- HTML全文浏览量: 6
- PDF下载量: 4
- 被引次数: 0
出版历程
- 收稿日期: 2024-05-29
- 修回日期: 2024-06-19
- 录用日期: 2024-10-29
- 刊出日期: 2025-06-09

Calculation methods of water-soil pressure for silty clay in Tianjin area

Tianjin Survey Design Institute Group Co., Ltd., Tianjin 300191, China

摘要

摘要: 对天津地区粉质黏土发育分布特征及其工程特性进行了详细介绍，针对天津地区基坑工程影响范围内的5个主要粉质黏土层的剪切指标相关关系开展研究，给出了各粉质黏土标准层的抗剪强度一元线性回归方程公式及剪切指标统计结果；结合天津地区多个典型工程案例，分析粉质黏土水土分算、水土合算的安全性、经济性，并通过基坑实测变形对比分析，探讨了天津地区粉质黏土直快水土合算、固快水土分算的适用性。研究结果表明：（1）天津地区粉质黏土层剪切指标c_q与c_cq、φ_q与φ_cq的关系曲线特征不具典型性，拟合优度检验统计量R²为0.2～0.3；（2）相比于粉质黏土直快水土合算，天津地区粉质黏土固快水土分算安全性较差；（3）无论是悬臂结构还是带支撑的围护结构，整体上粉质黏土直快水土合算计算的围护结构弯矩及剪力结果较水土分算小，经济性好；（4）实测变形分析表明，相比于粉质黏土固快水土分算，各项目围护结构计算的深层水平位移及周边地表沉降现场实测值与采用直快合算计算的结果更为接近。
- 粉质黏土 /
- 抗剪强度 /
- 水土压力 /
- 基坑支护
Abstract: This research takes the Tianjin area as an example to analyze the development, distribution, and engineering characteristics of silty clay in the region. A correlation study of the shear indices within the five silty clay layers affected by the foundation pit was conducted. The univariate linear regression equations and statistical results of shear indices for each standard layer of silty clay were provided. In conjunction with multiple typical engineering cases in the Tianjin area, the safety and economic analyses of silty clay water-soil separate accounting and combined accounting methods were carried out. Additionally, through comparative analysis of measured deformations of foundation pits, the applicability of direct quick water-soil combined accounting and fixed quick water-soil separate accounting methods for silty clay in the Tianjin area was discussed. The research findings are as follows: (1) In the Tianjin area, the relationships between the shear indices c_q and c_cq, as well as φ_q and φ_cq of the silty clay layer are not significant, with the coefficient of determination R² ranging between 0.2 and 0.3. (2) Compared to the direct quick water-soil combined accounting method, the safety of the fixed quick water-soil separate accounting method for silty clay in the Tianjin area is relatively poor. (3) Regardless of whether it is a cantilever structure or a supported retaining structure, the calculated bending moments and shear forces of the retaining structures using the direct quick water-soil combined accounting method are generally smaller than those using the water-soil separate accounting method, resulting in better economic efficiency. (4) Analysis of measured deformations indicates that the on-site measured values of deep horizontal displacement and surrounding surface settlement of the retaining structures for various projects are more closely aligned with the results calculated using the direct quick combined accounting method than with the fixed quick water-soil separate accounting method.
- silty clay /
- shear strength /
- water-soil pressure /
- foundation pit support

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图 1 剪切指标c_q与c_cq展点图

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图 2 剪切指标φ_q与φ_cq展点图

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图 3 南开区排桩+悬臂支护项目计算剖面（单位：m）

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图 4 围护结构顶部水平位移实测（JC2）

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图 5 桩身位移计算图

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图 6 基坑周边地表沉降对比曲线

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图 7 红桥区某排桩+内支撑支护计算剖面（单位：m）

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图 8 桩身位移计算对比曲线

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图 9 基坑周边地表沉降对比曲线

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表 1 直快与固快指标拟合优度检验R²统计结果

序号	方程	φ_q，φ_cq拟合R²	c_q，c_cq拟合R²
1	线性	0.27	0.30
2	对数	0.24	0.29
3	二次	0.16	0.26
4	三次	0.20	0.24
5	指数	0.25	0.25

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表 2 直快指标与固快指标拟合结果

序号	地层	线性回归公式	R²
1	4-1	φ_cq = 0.37·φ_q+13.43	0.41
1	4-1	c_cq = 0.23·c_q+15.88	0.23
2	6-1	φ_cq = 0.35·φ_q+15.15	0.42
2	6-1	c_cq = 0.13·c_q+14.23	0.21
3	6-4	φ_cq = 0.35·φ_q+14.68	0.41
3	6-4	c_cq = 0.22·c_q+14.10	0.29
4	7-1	φ_cq = 0.21·φ_q+17.32	0.24
4	7-1	c_cq = 0.15·c_q+16.18	0.34
5	8-1	φ_cq = 0.25·φ_q+17.21	0.26
5	8-1	c_cq = 0.25·c_q+15.38	0.23

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表 3 天津地区粉质黏土层剪切指标统计结果

层号	统计项目	c_q/kPa	φ_q/（°）	c_cq/kPa	φ_cq/（°）
4-1	最小值	8.00	10.30	9.00	11.80
	最大值	20	22	22	24
	标准值	13.69	15.81	15.04	18.08
	变异系数	0.224	0.179	0.234	0.174
	子样数	2875	2875	3966	3966
6-1	最小值	8	12	9	15.1
	最大值	17	26.4	20.5	28.5
	标准值	12.54	19.36	13.82	22.08
	变异系数	0.204	0.195	0.209	0.159
	子样数	2770	2770	3837	3837
6-4	最小值	6	12.5	9	13
	最大值	22	25	24	27
	标准值	12.91	19.48	14.65	20.99
	变异系数	0.281	0.161	0.244	0.153
	子样数	2515	2515	3447	3447
7-1	最小值	6	11.6	9	14.0
	最大值	21	26.1	24	28.0
	标准值	14.17	15.92	15.23	21.16
	变异系数	0.266	0.183	0.249	0.169
	子样数	948	948	1575	1575
8-1	最小值	8	12.60	10	14.5
	最大值	22	24.70	26	28.0
	标准值	14.04	17.69	15.56	20.85
	变异系数	0.233	0.192	0.244	0.177
	子样数	2625	2625	5521	5521

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表 4 典型工程案例粉质黏土水土分算、水土合算计算结果

序号	计算指标	南开区某工程（悬臂）		北辰区某工程（悬臂）		河北区某工程（一道撑）		和平区某工程（一道撑）		河东区某工程（一道撑）		红桥区某工程（二道撑）
序号	计算指标	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算
1	E_a/kN	612.8	597.8	1476.6	1137.4	1892.7	1676.1	1962.3	1869.5	1867.7	1855.9	2808.0	2336.6
2	E_p/kN	1527.3	1878.5	2353.6	1961.6	1320.7	1634.1	1842.7	1818.5	1732.4	1894.7	1780.5	2319.0
3	K_整稳	3.2	2.8	3.0	2.3	1.6	1.5	2.3	2.1	2.2	1.8	1.7	1.5
4	F_抗倾覆	2.1	2.6	1.2	1.6	1.0	1.5	1.3	1.3	1.2	1.3	0.9	1.4

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表 5 典型工程案例计算弯矩、剪力统计

序号	计算值	南开区某工程（悬臂）		北辰区某工程（悬臂）		河北区某工程（一道撑）		和平区某工程（一道撑）		河东区某工程（一道撑）		红桥区某工程（二道撑）
序号	计算值	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算	固快分算	直快合算
1	最大弯矩 /（kN·m）	−215.3	−145.3	−594.7	−585.6	959.1	938.8	1084.5	832.4	953.8	889.7	1323.4	986.1
2	最大剪力 /kN	73.6	54.6	152.3	153.2	−365.6	−335.7	−354.4	−299.6	280.7	262.7	−576.4	−463.3

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