| 均质土壤承压下陷模型改进及验证 |
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| 引用本文： | 赵家丰,汪伟,孙中兴,苏续军.均质土壤承压下陷模型改进及验证[J].农业工程学报,2016,32(21):60-66. |
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| 作者姓名： | 赵家丰 汪伟 孙中兴 苏续军 |
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| 作者单位： | 军械工程学院火炮工程系,石家庄,050000 |
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| 基金项目： | 国家自然科学基金（51575523）；军内科研项目 |
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| 摘 要： | 针对传统土壤承压模型依赖拟合原位承载试验曲线的复杂性或建立在土壤力学参数基础上的预测模型的理想化等问题,该文提出一种改进的土壤承压下陷模型。依据地面力学和土壤力学相关理论将土壤承压力学模型分3类进行简要介绍,分析其各自特点和参数意义。结合土壤承压极限理论的指数形式,提出改进的土壤承压模型。利用庄继德等人的相关试验研究结果进行验证,结果表明砂性土、水稻土的土壤承压下陷计算预测曲线与实际拟合曲线吻合度较好,其中砂土试验的Bekker下陷曲线与改进模型计算所得曲线的决定系数R2为0.9998;利用Bekker文献中的黏性土试验参数数据进行验证,计算所得土壤极限应力值与相应位置贝氏方程拟合应力值误差在5%~21%之间,土壤变形指数求解值与实际值误差在7%~36%之间。该模型普适性、准确性较强,可在测得土体基本力学参数的基础上预测载荷下陷曲线,为研究车辆行驶下陷提供参考。
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| 关 键 词： | 土壤力学 车辆 下陷 地面力学 平板 土壤承压-下陷模型 极限承载力 |
| 收稿时间： | 2016/1/10 0:00:00 |
| 修稿时间： | 2016/9/19 0:00:00 |
Improvement and verification of pressure-sinkage model in homogeneous soil |
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| Zhao Jiafeng,Wang Wei,Sun Zhongxing and Su Xujun.Improvement and verification of pressure-sinkage model in homogeneous soil[J].Transactions of the Chinese Society of Agricultural Engineering,2016,32(21):60-66. |
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| Authors: | Zhao Jiafeng Wang Wei Sun Zhongxing and Su Xujun |
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| Institution: | Artillery Engineering,Ordnance Engineering College, Shijiazhuang 050000, China,Artillery Engineering,Ordnance Engineering College, Shijiazhuang 050000, China,Artillery Engineering,Ordnance Engineering College, Shijiazhuang 050000, China and Artillery Engineering,Ordnance Engineering College, Shijiazhuang 050000, China |
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| Abstract: | Vehicles mobility performance relies on the sustentation of the soil. The sinkage and driving resistance are closely related to soil pressure-bearing characteristics. There are many soil pressure-sinkage theories that allow the designers of off-road vehicles to understand and predict vehicle mobility performance over the soft soil. In this paper, these theories were firstly divided into 3 categories in accordance with the mechanism and terramechanics after a brief introduction. Then their characteristics, applicability and meaning of equations were analyzed in detail. Bekker proposed the pressure-sinkage model based on the previous research and got soil subsidence parameters by loading plate bearing. The method is simple and still widely used today, but it is difficult in obtaining in-suit bearing test curve. American scholar Karafiath et al. predicted soil subsidence pressure curve by means of soil mechanics method, which is ideal and does not agree with the actual soil pressure stress value, especially for sandy compacted soil. British scholar Reece et al. described soil subsidence pressure curve combined with the ultimate bearing capacity concept in soil mechanics and Bekker’s methods. It is relatively accurate as it has a comparative system theory. On this basis, in order to achieve an accurate prediction of soil pressure-subsidence curve by soil parameters, a new plate pressure-sinkage model was proposed combined with the exponential model and soil mechanics methods. Using the mechanical parameters in Bekker’s literature about clayed soil, we found that the error between the ultimate bearing capacity and the corresponding pressure values calculated by Bekker’s equation was about from 5% to 21%, and the error between the sinkage index value calculated and the actual value was about from 7% to 36%. Using the relevant research results from Zhuang Jide et al, it showed a very high coefficient between the predicted curve by parameters calculation and the actual curve obtained from the tests in sandy soil. The correlation coefficient between the subsidence curve with the improved model and the curve by calculating in the sandy soil test was 0.9998. The error between the ultimate bearing capacity and the corresponding pressure values calculated by Bekker’s equation was about 9.26%, and the error between the sinkage index value calculated and the actual value was about 2.04%. We also used the soil test data of paddy soil in College of Engineering, Nanjing Agricultural University for validation. The deformation index changed with the moisture content. Curve coincidence degree was better comparing the field measured one with the one from the improved model, in which the sinkage index value ranged from 0.32 to 0.52. Therefore, the model is valid and stable for sticky and frictional soils. It is predictable that the load curve can be constructed using the mechanical parameters of soil, which provides a new theoretical idea for solving pressure-sinkage problem. It should be mentioned that, these models are applicable for homogeneous soil but not for layered soil, such as southern paddy fields. Also we find that the sinkage index value of bearing-pressure model is stable, and whether it can be used as soil confined nature eigenvalue is worthy of further discussion. Also, although the improved model has ideal effects in these examples, its specific soil type and boundary conditions still need to be validated. |
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| Keywords: | soil mechanics vehicle sinkage terramechanics plate bearing pressure-sinkage model ultimate bearing capacity |
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