【摘要】：作為地下綜合管廊、地鐵、隧道等建設(shè)工程中常見的軟弱不良地層——粉細砂土層,因粒徑小、結(jié)構(gòu)松散、穩(wěn)定性差,故其注漿加固防滲處理工作,一直是地質(zhì)工程界研究的熱點。聲頻振動鉆進注漿法利用粉細砂層易液化特性,采用高頻振動和高壓力提高漿液的擴散性,是一種新型的、有前景的注漿工藝方法。本文對該新型注漿方法進行了探索研究。首先,調(diào)研漿液的流變性,通過對注漿漿液在地層中的擴散模型研究,基于聲頻振動鉆進注漿機理,建立聲頻振動注漿模型。其次,針對目前振動注漿室內(nèi)試驗的不足,研制了聲頻振動鉆進注漿試驗平臺,包括振動發(fā)生裝置、傳動桿體、約束支撐裝置、砂土箱、漿液輸送管路等。試驗平臺可實現(xiàn)振源特性相關(guān)的振動頻率、激振力、振動時間的調(diào)控,并可調(diào)節(jié)漿液的壓力和流量。再次,根據(jù)粉細砂地層的主要工程性質(zhì),配制實驗用注漿漿液,并對漿液的理化性質(zhì)進行測試研究。隨后,進行靜壓注漿試驗,確定試驗砂土的適宜注漿壓力并作為后續(xù)試驗的對照實驗。最后,開展聲頻振動注漿模擬試驗研究,并得到以下結(jié)論:(1)振源振頻越接近砂土體的固有頻率,漿液的注入量及擴散半徑越大,注漿加固效果越好。當(dāng)振頻與粉細砂土固有頻率偏差較大時,振動沖擊作用改善注漿環(huán)境的效果不夠明顯,反而會因為振沖作用使孔壁間隙擴大,尤其在鉆桿埋深較淺、上覆土壓力較小時,更容易產(chǎn)生冒漿,不利于注漿效果。所以根據(jù)實際工況選擇適宜振頻,才能實現(xiàn)工程施工的優(yōu)質(zhì)高效。(2)激振力的大小對聲頻振動注漿效果的影響并不明顯,在適宜頻率的振動作用下,注漿效果不會隨激振力的改變而發(fā)生實質(zhì)性變化。(3)振動作用起始階段,漿液擴散速率增長較快,漿液固結(jié)體迅速變大。隨著振動作用時間的延長,漿液擴散半徑也會逐漸增大,只是增速放緩,最后速率趨近于零。綜上所述,振動頻率是決定注漿效果的關(guān)鍵性因素。針對不同粉細砂地層,調(diào)節(jié)振動頻率,配合高壓進行注漿作業(yè),可有效改善地層可注性,提升漿液的注入量,擴大漿液的擴散半徑,增大漿液固結(jié)體體積,取得良好的注漿效果。
[Abstract]:As a common weak and bad stratum in underground comprehensive pipe gallery, subway, tunnel and other construction projects, the silty sand soil layer, because of its small particle size, loose structure and poor stability, is used to reinforce and prevent seepage treatment by grouting. It has always been a hot spot in the field of geological engineering. Sound frequency vibration drilling grouting method is a new and promising grouting method, which utilizes the liquefaction characteristics of fine silty sand layer and uses high frequency vibration and high pressure to improve the diffusivity of the slurry. In this paper, the new grouting method is studied. Firstly, the rheological behavior of grouting fluid is investigated, and the acoustic vibration grouting model is established by studying the diffusion model of grouting fluid in stratum and based on the mechanism of acoustic vibration drilling grouting. Secondly, aiming at the deficiency of vibration grouting laboratory test at present, an audio frequency vibration drilling grouting test platform is developed, including vibration generator, transmission rod body, restraint support device, sand box, slurry conveying pipeline and so on. The test platform can adjust the vibration frequency, exciting force and vibration time, and adjust the pressure and flow rate of the slurry. Thirdly, according to the main engineering properties of silty sand formation, the grouting fluid for experiment is prepared, and the physical and chemical properties of the slurry are tested and studied. Then, a static pressure grouting test was carried out to determine the appropriate grouting pressure of the test sand and to be used as a control experiment in the follow-up test. Finally, the simulation experiment of acoustic vibration grouting is carried out, and the following conclusions are obtained: (1) the vibration frequency of vibration source is close to the natural frequency of sand body, the larger the injection amount and diffusion radius of slurry, the better the grouting reinforcement effect. When the vibration frequency and the natural frequency of silty sand soil deviate greatly, the effect of vibration shock on improving grouting environment is not obvious, but the hole wall gap will be enlarged because of vibration and impact, especially when the drill pipe is buried in shallow depth and the overlying earth pressure is small. It is easier to produce grouting, which is not conducive to grouting effect. Therefore, according to the actual conditions, select the appropriate vibration frequency, in order to achieve the high quality and efficiency of engineering construction. (2) the magnitude of the exciting force on the sound vibration grouting effect is not obvious, under the appropriate frequency of vibration, The grouting effect will not change materially with the change of the exciting force. (3) in the initial stage of vibration the slurry diffusion rate increases rapidly and the slurry consolidation body increases rapidly. With the extension of vibration time, the slurry diffusion radius will gradually increase, but the growth rate will slow down, and the final rate will reach zero. In conclusion, the vibration frequency is the key factor to determine the grouting effect. According to different silty sand strata, regulating vibration frequency and grouting with high pressure can effectively improve the injectability of stratum, increase the injection quantity of slurry, enlarge the diffusion radius of slurry, and increase the volume of slurry consolidation body. Good grouting effect has been achieved.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU753.8
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本文編號：2393380