二次拋物線型強(qiáng)度準(zhǔn)則下黃土主動土壓力計(jì)算

關(guān)曉迪 曹周陽 馬迪 朱勇鋒 何盛東

摘 要：為了解決基于Mohr-Coulomb強(qiáng)度理論求解出的黃土主動土壓力往往偏離實(shí)際的問題，本文基于二次拋物線型強(qiáng)度準(zhǔn)則，通過對墻后填土展開主動極限平衡狀態(tài)分析，推導(dǎo)了基于二次拋物線準(zhǔn)則的黃土主動土壓力解析解。研究結(jié)果表明：基于二次拋物線型強(qiáng)度準(zhǔn)則的黃土主動土壓力呈非線性分布，在填土拉張區(qū)其主動土壓力值小于朗肯主動土壓力值，且基于二次拋物線型強(qiáng)度準(zhǔn)則的填土拉張區(qū)開裂深度明顯小于基于Mohr-Coulomb理論的拉張區(qū)開裂深度;在填土壓剪區(qū)，填土深度越大則其所受圍壓越大，基于二次拋物線型強(qiáng)度準(zhǔn)則的主動土壓力明顯大于朗肯主動土壓力。因此，在應(yīng)力水平較大或負(fù)應(yīng)力水平時(shí)，基于二次拋物線型強(qiáng)度準(zhǔn)則的黃土主動土壓力更貼近實(shí)際。

關(guān)鍵詞：黃土;抗拉強(qiáng)度;內(nèi)摩擦角;二次拋物線型強(qiáng)度準(zhǔn)則

中圖分類號：TU43 ? ? 文獻(xiàn)標(biāo)識碼：A ? ? 文章編號：1003-5168（2021）21-0071-03

Calculation of Active Earth Pressure of Loess based On Quadratic Parabolic Strength Criterion

GUAN Xiaodi1? ? CAO Zhouyang2? ? MA Di1? ? ZHU Yongfeng3? ? HE Shengdong2

（1. Institute of Geotechnical Engineering， Xi'an University of Technology， Xi'an Shaanxi 710048;

2. School of Civil Engineering and Architecture， Zhengzhou University of Aviation Industry Management， Zhengzhou Henan 50046;3. School of Geoengineering and Surveying and Mapping， Chang'an University， Xi 'an Shaanxi 710048）

Abstract： In order to solve the problem that the active earth pressure of loess calculated based on Mohr-Coulom strength theory often deviates from the reality. In this paper， based on the quadratic parabolic strength criterion， the analytical solution of the active earth pressure of loess based on the quadratic parabolic criterion is derived by analyzing the active limit equilibrium state of the backfill. The results show that the active earth pressure of the loess is non- linear based on the quadratic parabolic strength criterion. The active earth pressure is less than that of Rankine in the filling tension area. The crack depth based on quadratic parabolic strength criterion is obviously smaller than that based on Mohr-Coulomb theory. In the compression and shear zone of filling， the greater filling depth is， the greater the confining pressure is， and the active earth pressure based on the quadratic parabolic strength criterion is obvious- ly greater than the active earth pressure of Rankine. Therefore， when the stress level is large or negative， the active earth pressure of loess based on the quadratic parabolic strength criterion is more practical.

Keywords： loess; tensile strength; angle of internal friction; quadratic parabolic strength criterion

擋土墻土壓力計(jì)算是支護(hù)結(jié)構(gòu)設(shè)計(jì)的主要依據(jù)之一[1]?；诓煌瑥?qiáng)度理論的擋土結(jié)構(gòu)的土壓力計(jì)算也是不同的，應(yīng)用最為廣泛的經(jīng)典土壓力理論是基于Mohr-Coulomb強(qiáng)度理論得出的，然而采用Mohr-Coulomb強(qiáng)度理論對工程案例中土壓力進(jìn)行研究往往有其局限性，使得土壓力的計(jì)算結(jié)果偏離實(shí)際。因此，現(xiàn)階段土壓力理論的相關(guān)研究仍然是巖土工程的熱門問題。

蔣莼秋[2]基于卡崗的研究成果，推導(dǎo)出擋土墻后填土面為水平、墻背坡度取隨機(jī)值時(shí)的土壓力非線性解。謝群丹等[3]通過對擋土結(jié)構(gòu)與土進(jìn)行空間相互作用分析，推導(dǎo)了黏性土與無黏性土的主動與被動土壓力統(tǒng)一解。范文等[4]通過采用塑性極限上限分析法，推導(dǎo)了基于統(tǒng)一強(qiáng)度理論的土壓力計(jì)算公式。張常光等[5]合理考慮中間主應(yīng)力效應(yīng)，推導(dǎo)了非飽和土雙應(yīng)力狀態(tài)變量抗剪強(qiáng)度統(tǒng)一解。馬林等[6]提出了結(jié)構(gòu)性對黃土力學(xué)和變形特性影響的適用表達(dá)式。上述研究基于不同的強(qiáng)度理論，發(fā)展和完善了擋土結(jié)構(gòu)土壓力計(jì)算。