近年來彈性波應用在孔彈性介質中之理論研究受到眾多學者的關注，尤其是在含二相或多相非混合流體之孔隙介質中的傳遞特性更引起廣泛討論。目前已經知道彈性波在含二相流體之孔隙介質中傳遞會對土壤保水曲線造成影響，但至今尚未找出保水曲線受彈性波震動頻率影響之特性，也未知彈性波對土壤影響為暫時性或是永久性。
本研究以砂箱試驗將砂箱內土壤分為三層（下、中、上層）分別探討3種頻率（150Hz、300Hz、450Hz）的聲波（彈性波）對乾燥過程之保水曲線的影響與聲波影響前後保水曲線之變化，另外再觀察不同深度下的保水曲線受聲波影響之情況。
根據實驗結果發現聲波可以使土體產生膨脹或沉陷，當聲波使土體產生膨脹後，土體能以自然沉陷而恢復到聲波影響前之狀態；反之當聲波使土體沉陷後，土體則無法恢復到聲波影響前之狀態，故認定聲波造成土體膨脹為暫時性影響；造成土體沉陷為永久性影響，也從回歸資料中發現形狀因子α會隨著毛細張力減少而上升，而形狀因子n則會隨毛細張力減少而下降。
此外從不同深度之土壤受聲波影響下的實驗結果發現，聲波使土體膨脹或沉陷之程度會因土壤深度不同而改變，但使土體產生膨脹或是沉陷僅取決於聲波之頻率，並不會隨著土壤深度產生交替變化。

Over the past few decades, theoretical and experimental studies on the connection between elastic wave attributes and the physical properties of a fluid-bearing porous medium have attracted the attention of many scholars in fields of porous medium flow and hydrogeology. It has been previously demonstrated that the transmission of elastic waves into a porous medium containing two immiscible fluids will have an effect on the water retention curve, but it remains elusive how the water retention curve will be affected by the frequency of elastic vibration waves or whether the effect on the soil is temporary or permanent.
This research is based on a sand box test in which the soil is divided into three layers (lower, middle, and upper layers). In this case, we discuss different impacts on the water retention curve during the drying process under sound waves (elastic waves) subject to three frequencies (150Hz, 300Hz, and 450Hz), respectively. The change in the water retention curve before and after the effect is then discussed. In addition, how sound waves affect the water retention curve at different depths is also observed.
According to the experimental results, we find that sound waves can cause soil either to expand or to contract. When the soil is induced to expand due to sound waves, it can contract naturally and return to the condition it was before the influence of the sound waves. On the contrary, when the soil is induced to contract, it is unable to return to its initial condition. Based on the results discussed above, it is suggested that sound waves causing soil to expand have a temporary impact while those causing soil to contract have a permanent impact.
In addition, our experimental results show how sound waves affect the water retention curve at different depths. The degree of soil expansion and contraction caused by the sound waves is different at various soil depths. Nevertheless, the expanding or contracting of soil is only subject to the frequency of sound waves. These changes are not altered as different soil depths.

1.Alessi, S., L. Prunty, and W. H. Schu (1992), Infiltration simulations among five hydraulic property model, Soil Science Society of America Journal, Vol. 56, pp. 675-682.
2.Biot, M. A. (1956a), Theory of propagation of elastic waves in a fluid saturated porous solid, Ⅰ. Low-frequency range, The Journal of the Acoustical Society of America, 28 (2), pp. 168-178.
3.Biot, M. A. (1956b), Theory of propagation of elastic waves in a fluid saturated porous solid, Ⅱ. Higher frequency range, The Journal of the Acoustical Society of America, 28 (2), pp. 179-191.
4.Brooks, R. H., and A. T. Corey (1964), Hydraulic properties of porous media, Colorado State University, Hydrology Paper, No. 3.
5.Brutsaert, W. (1964), The propagation of elastic waves in unconsolidated unsaturated granular mediums, J. Geophys. Res. , 69 (2), pp. 243-257.
6.Brutsaert, W., and J. N. Luthin (1964), The velocity of sound in soils near the surface as a function of the moisture content, J. Geophys. Res. , 69 (4), pp. 643-652.
7.Clapp, R. B., and G. M. Hornberger (1978), Empirical equations for some soil hydraulic-properties, Water Resources Research, Vol. 14, pp. 601-604.
8.Cowin, S. C. (1999), Bone poroelastictiy, Journal of Biomechanics, 32 (3), pp. 217-238.
9.Gadiev, S. M. (1977), Use of vibrations in oil producing (Isopol'zovaniiye vibratsii v dobyche nefti), Nedra Press (in Russian).
10.Geller, J. T., and L. R. Myer (1995), Ultrasonic imaging of organic liquid contaminants in unconsolidated porous media, J. Contam. Hydrol., 19 (2), pp. 85–104.
11.Gilani, S. A., A. Kikuchi and K. N. Watanabe (2009), Genetic variation within and among fragmented populations of endangered medicinal plant, Withania coagulans (Solanaceae) from Pakistan and its implications for conservation, African Journal of Biotechnology, 8 (13), pp. 2948-2958.
12.Hickey, C. J. and J. M. Sabatier (1997), Choosing Biot parameters for modeling water-saturated sand, The Journal of the Acoustical Society of America, 102 (3), pp. 1480-1484.
13.Huang, H.-C., Y.-C. Tan, C.-W. Liu, and C.-H. Chen (2005), A novel hysteresis model in unsaturated soil, Hydrological Processes, Vol. 19, pp. 1653-1665.
14.Hughes, E. R., T. G. Leighton, G. W. Petley, P. R. White, and R. Cm. Chivers(2003), Estimation of critical and viscous frequencies for Biot theory in cancellous bone, Ultrasonics, 41 (5), pp. 365-368.
15.Hutson, J. T., and A. Cass (1987), A retentivity function for use in soil water simulation models. Journal of Soil Science, Vol. 38, pp. 105-113.
16.Jacinto, A. C., M. V. Villar, and A. Ledesma (2012), Influence of water density on the water-retention curve of expansive clays, Ge´otechnique 62, No. 8, pp. 657–667.
17.Jaynes, D. B. (1984), Comparison of soil-water hysteresis models, Journal of Hydrology, Vol. 75, pp. 287-299.
18.Ke, K. Y., Y. C. Tan, C. H. Chen, and H. T. Lin (2012), Characterizing the hydraulic properties of unsaturated sand considering various porosities and drying-wetting paths of the retention curve, Hydrological Processes, doi:10.1002/hyp.9246.
19.Kool, J. B., and J. C. Parker (1987), Development and evaluation of closed-form expressions for hysteretic soil hydraulic properties, Water Resources Research, Vol. 23, pp. 105-114.
20.Kim, Y. U., and M. C. Wang (2003), Effect of ultrasound on oil removal from soils, Ultrasonics, 41 (7), pp. 539-542.
21.Lo, W. C., G. Sposito, and E. Majer (2005), Wave propagation through elastic porous media containing two immiscible fluids, Water Resources Research, Vol. 41, W02025.
22.Lo, W. C., G. Sposito and Y. H. Huang (2012), Modeling Seismic Stimulation: Enhanced Non-aqueous Fluid Extraction from Saturated Porous Media Under Pore-pressure Pulsing at Low Frequencies, Journal of Applied Geophysics, Vol. 78, pp. 77-84.
23.Oelze, M. L. and W. D. O'Brien (2002), Frequency-dependent attenuation- compensation functions for ultrasonic signals backscattered from random media, Journal of the Acoustical Society of America, Vol. 111, pp. 2308-2319.
24.Moore, H. M. and K. Attenborough (1992), Acoustic determination of air-filled porosity and relative air permeability of soil, Journal of Soil Society, Vol. 43, pp. 211-228.
25.Sabatier, J. M., H. Hess, W. P. Arnott, and K. Attenborough, M. J. M. Romkens, and E. H. Grissinger (1990), In situ measurements of soil physical properties by acoustic technique, Soil Science Society of America Journal, Vol. 54, pp. 658-672.
26.Scott, P. S., G. J. Farquhar, and N. Kouwen (1983), Hysteretic effects on net infiltration. Advances in Infiltration: proceedings of the National Conference on Advances in Infiltration, 11-83, pp. 452-412.
27.van Genuchten, M. T. (1980), A closed-form equation for predicting the hydraulic conductivity of unsaturated soils, Soil Science of America journal, 44 (5), pp. 892-898.
28.Velea, D., F. D. Shields, and J. M. Sabatier (2000), Elastic wave velocities in partially saturated Ottawa sand: Experimental results and modeling, Soil Science Society of America Journal, Vol. 64, pp. 1226-1234.
29.Wu, T. T., J. S. Fang, and P. L. Liu (1995), Detection of the depth of a surface-breaking crack using transient elastic waves, Journal of the Acoustical Society of Americal, Vol. 97, pp. 1678-1686.
30.王燦銘(2002)，遲滯土壤水分傳輸數值模式之研究，國立臺灣大學生物環境系統工程研究所碩士論文。
31.牛建軍、杜立志、谷成(2004)，岩溶探測中的彈性波CT方法，吉林大學學報，第34卷，第4期，頁630-633。
32.林子雲(2003)，鹽化土壤遲滯現象之研究，國立臺灣大學生物環境系統工程學系研究所碩士論文。
33.倪勝火(2006)，土壤力學實驗手冊，國立成功大學土木工程學系。
34.莊永源(2013)，震波對提升孔彈性介質中流體流量之實驗研究，國立成功大學水利及海洋工程研究所碩士論文。
35.陳玟潔(2012)，壓力波對保水曲線特性之實驗影響評估，國立成功大學水利及海洋工程研究所碩士論文。
36.曾燕翔(2016)，動態毛細壓力於土壤保水曲線之變化分析及現地長期入滲監測試驗，國立臺灣海洋大學應用地球科學研究所碩士論文。
37.黃漢誠(2004)，未飽和層土壤水分遲滯效應之研究，國立臺灣大學生物環境系統工程研究所博士論文。
38.楊佶欽(2014)，非飽和土壤乾燥保水曲線在震動環境下動態變化之研究，國立成功大學水利及海洋工程研究所博士論文。
39.劉明鑫(1999)，非破壞檢測混凝土工程性質之研究，國立臺灣科技大學營建工程研究所碩士論文。