- 摘 要
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（重慶市建筑科學研究院， 重慶 400015）
［摘要］分析了巖石單軸抗壓強度折減法確定地基承載力特征值時存在的問題，通過對大量的原位平板巖基載荷試驗與同條件巖石單軸抗壓強度試驗工程案例進行對比分析，討論了圍壓約束效應對巖基承載力的影響。結(jié)果表明，考慮圍壓約束效應影響時，地基承載力可提高1-5～2-8倍；砂巖的圍壓約束效應較泥巖高；具有95%保證率時，砂巖的圍壓效應系數(shù)為1-7，泥巖為1-5。根據(jù)統(tǒng)計分析結(jié)果，提出了重慶地區(qū)的基于圍壓約束效應影響的巖石單軸抗壓強度折減法確定的地基承載力特征值計算公式，該公式計算的地基承載力特征值較《建筑地基基礎(chǔ)設(shè)計規(guī)范》(GB 50007—2011)計算式的結(jié)果有大幅提高且有足夠的安全儲備，經(jīng)濟效益明顯。
［關(guān)鍵詞］圍壓約束效應； 單軸抗壓強度； 原位載荷試驗； 軟巖地基； 承載力特征值
中圖分類號：TU318， TU391文獻標識碼：A文章編號：1002-848X(2017)09-0090-04
Experiment study on bearing capacity of soft rock foundation in Chongqing area
Li Chengfang, Chen Kui, Xiong Qidong, Zhong Wei
(Chongqing Institute of Building Research, Chongqing 400015, China)
Abstract:The problem for determining the characteristic value of bearing capacity of the rock foundation using the rock uniaxial compressive strength reduction method was analyzed. Influence of confining pressure effect on the bearing capacity of the rock foundation was discussed through a large number comparative analyses on engineering cases of in-situ slab rock foundation loading tests and uniaxial compressive strength tests on rock with the same conditions. The results show that foundation bearing capacity can be increased by 1-5 to 2-8 times considering the influence of confining pressure effect. Confining pressure effect of sandstone is higher than that of mudstone. Confining pressure effect of sandstone is 1-7 and confining pressure effect of mudstone is 1-5 with a 95% guarantee rate. According to the results of statistical analysis, the calculation formula of foundation bearing capacity determined by the uniaxial compressive strength reduction method of the rock based on confining pressure effect in Chongqing area was presented. The calculated characteristic value of bearing capacity of foundation by the formula is significantly higher than that of the Code for design of building foundation (GB 50007—2011) and this formula has sufficient safety reserves with obvious economic benefits.
Keywords:confining pressure effect; uniaxial compressive strength; in-situ loading test; soft rock foundation; characteristic value of bearing capacity
*重慶市自然科學基金項目（CSTC,2010BB7334）。
作者簡介：李成芳，博士，教授級高級工程師，一級注冊結(jié)構(gòu)工程師，Email: LCF9133@163.com。
