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摘   要

近年來，生態(tài)護坡技術在工程建設中的應用越來越廣泛。但是生態(tài)護坡效果的檢驗需要植物根系的生長規(guī)律。根系是植物體的地下部分，而常規(guī)土體是不可見的導致植物根系生長無法有效觀測。本文基于人工合成透明土材料，采用與天然土具有相似巖土性質的人工合成透明材料來模擬自然土體，從而實現植物根系在“土體”中生長過程的可視化試驗研究。通過對比天然砂土、天然黏土、水族珠透明土中植物莖、根的生長情況觀察，以及后期含根復合土體強度的測量研究植物根系的生長規(guī)律。初步探討植物根系生長規(guī)律對生態(tài)護坡的作用。本文主要開展的工作內容有：

（1）利用河海大學路基路面研究實驗室空余場地模擬高速公路氣候條件下，香根草、高羊茅在水族珠透明土、天然砂土以及天然黏土中的生長情況，記錄植物在不同土體中植物莖長、根系的生長規(guī)律與差異，分析不同植物的生長習性，為高速公路植物物種選擇提供依據。同時，利用水族珠透明土直接觀測植物根系生長情況。試驗結果表明，水族珠透明土可以作為可視化研究植物根系生長規(guī)律研究的材料。

（2）基于三軸固結不排水試驗方法，研究在不同圍壓、不同含根率情況下熔融石英砂透明土根土復合體的應力-應變關系、強度特征和破壞形態(tài)；并與福建標準砂試驗結果進行對比分析。分析對比不同工況下，熔融石英砂透明土含根復合土體的力學性能，并與不含根土體形成對比，得出根系對于土體剪切強度的影響。對比不同含根率復合土體的力學性能，分析得出熔融石英砂透明土含根量的最佳區(qū)域。

本文的亮點及難點在于：（1）水族珠配制的透明土中種植植物，并觀察其生長狀況，并與天然砂土、天然黏土中的植被進行對比分析；（2）研究了熔融石英砂透明土含根復合透明土體的力學性能，獲得熔融石英砂透明土含根量的最佳區(qū)域，為植物根系可視化研究模型試驗提供了參考依據。

關鍵詞：透明土；生態(tài)護坡；含根復合土體；三軸試驗；力學特性

 

Abstract

In recent years, ecological slope protection has been applied into construction. However, the root system growth rule should be imported to test the results of such method. Root system is the underground part of plants, which is unable to be observed, due to the unobservable of tradition soil. Crystal soil materials are artificially synthesized in the research. Artificially synthesized transparent materials, which have the similar geotechnical qualities with nature soil, are applied to simulate nature soil, to visualize the growth process of plants root system in so-called soil. The effects of ecological slope protection are primarily studied, through comparing the growth of the plant stem and root in natural sand, natural clay and Crystal soil, as well as measuring the strength of composite soil that contains root. Research contents are listed below:

(1) Growth of votive grass, tall fescue in crystal soil, natural sand, and natural clay soil under highway climatic conditions are simulated in road research laboratory in Hohai University. Differences of plants stem length and roots are recorded, and growth habits of plants in different soil are analyzed. Such results support the decision of plants selection on highways. Meanwhile, growth of plants roots systems is observed in crystal soil. The results show that crystal soil assists the visualization of growth rule research of plants root system.

(2) Stress-strain relationship, strength characteristics and failure pattern of root-soil composite under different confining pressure and root content are attained, based on CU test method. The results of such tests are compared with the ones of Fujian standard soil. Effects that roots have on shear strength of soil are acquired through analyzing mechanical properties of composite soil and comparing them with that of nature soil. Optimum threshold of root content is acquired through comparing the mechanical properties of composite soil of different root contents.

The highlights of this paper: (1) lie with preparing plants in crystal soil, and observing their growth, comparing such conditions with that in natural sand and clay. (2) Mechanical properties of root-soil composite are acquired through triaxial test, which greatly supports the visualization research model of plants root system.

Key words: transparent soil; ecological revetment; soil containing root complex; triaxial test; mechanical properties