軟土地區(qū)既有建筑物質(zhì)量事故分析與加固
發(fā)布時間：2018-11-24 瀏覽次數(shù)：2571
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摘 要
由于軟土具有含水量高、孔隙比大、壓縮性高、抗剪強度低、靈敏度高、具流變性等工程特點，故軟土地區(qū)建筑物發(fā)生傾斜破壞等質(zhì)量事故的概率比較高。對發(fā)生質(zhì)量事故的建筑物如何進行分析、處理是本文的研究內(nèi)容。
本文以軟土的特性當作為研究的出發(fā)點，對既有建筑物的質(zhì)量事故表現(xiàn)、質(zhì)量事故原因、原建筑物的鑒定評估、地基基礎承載力的充分利用及適用于軟土地區(qū)的加固方法進行了分析、探討，其目的在于建立一套從“事故表現(xiàn)----原因分析----原建筑物性能評估----地基基礎承載力的充分利用”，到“選擇加固方法”的機制，使得在既有建筑物加固時更具針對性。
要想更有效、更經(jīng)濟地對既有建筑物進行加固，應充分利用既有建筑物地基基礎承載力潛力。本文根據(jù)軟土的工程特性，從土力學的角度出發(fā)，對軟土在建筑物荷載作用下強度的增長進行了分析研究，推導了其承載力隨時間增長的公式。對于既有建筑物失效樁基承載力的計算，本文提出，應根據(jù)具體的失效原因進行計算。對由于軟土固結所產(chǎn)生的負摩擦力對樁基承載力的影響，具體進行了分析。當無法確定樁基失效的原因時，本文建議按實際的沉降量估算其承載力潛力，并提出了經(jīng)驗公式。
對既有建筑物加固，本文總結了其原則和程序。對適于軟土地區(qū)的既有建筑物的加固尤其地基基礎加固，文中根據(jù)已有的文獻結合本人經(jīng)驗對此進行了總結。
在具體的工程實踐中，本文以南海市某建筑物的加固為例，對前述的分析、評估與加固方法進行了應用，并取得了良好的效果。
Abstract
The rate which constructions are inclined and destroyed in the district of soft soil is high because soft soil has the engineering characters of high water content, big coid ratio, high compressibility, low shear strength, high sensitivity and rheology. It is the thesis’s study content how to analyse and deal with the existing building’s problems in quality.
As study’s starting with soft soil’s characters,the questions about the representations and causes of quality accident, judgement and appraisement on existing building, full use of bearing capacity of ground foundation and reinforcing ways applying to the districts of soft soil are analyzed and discussed herein. The aim is to build a suit of mechanism from ‘accident representations -- causes analysis-- existing building appraisement of capacity--ground foundation bearing capacity full use’ to ‘reinforcing ways choice’,so that the pertinence is better when the existing building is reinforced.
The potential of bearing capacity of ground foundation should be taken full advantage of if the existing building need be reinforced more effectively and more economically. Soft soil strength’s increasing in the effect of buildings load is analysed and studied from angle of soil mechanics in term of soft soil engineering characters while the formulas of bearing capacity increasing with time are put forward herein. To ineffective piles in existing building , its bearing capacity should be calculate in term of material cause.The effect on pile of negative friction because of soft soil consolidation is analysed too in detail. When the cause why the piles are ineffective cannot be confirmed, it is suggested to count its potential of bearing capacity according to actual settlement value and its experimental formulas are put forward herein.
The reinforcing principle and process on existing building are summarized herein. The summarization is done too about reinforcement ways special to foundation reinforcement of existing buildings applying to soft soil according to existing literatures and author’s experiments.
In real engineering practice, forementioned ways of analysing, appraising and reinforcing have been applied and gained a favorable effect by the instance of a building reinforcement in Naihai.
Key words: soft soil; analysis of accident; bearing capacity; ground foundation; reinforcement and rectifying deviation