植物根系生长可视化模型试验研究.doc

2.79万字           59页

摘   要

近年来，生态护坡技术在工程建设中的应用越来越广泛。但是生态护坡效果的检验需要植物根系的生长规律。根系是植物体的地下部分，而常规土体是不可见的导致植物根系生长无法有效观测。本文基于人工合成透明土材料，采用与天然土具有相似岩土性质的人工合成透明材料来模拟自然土体，从而实现植物根系在“土体”中生长过程的可视化试验研究。通过对比天然砂土、天然黏土、水族珠透明土中植物茎、根的生长情况观察，以及后期含根复合土体强度的测量研究植物根系的生长规律。初步探讨植物根系生长规律对生态护坡的作用。本文主要开展的工作内容有：

（1）利用河海大学路基路面研究实验室空余场地模拟高速公路气候条件下，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长情况，记录植物在不同土体中植物茎长、根系的生长规律与差异，分析不同植物的生长习性，为高速公路植物物种选择提供依据。同时，利用水族珠透明土直接观测植物根系生长情况。试验结果表明，水族珠透明土可以作为可视化研究植物根系生长规律研究的材料。

（2）基于三轴固结不排水试验方法，研究在不同围压、不同含根率情况下熔融石英砂透明土根土复合体的应力-应变关系、强度特征和破坏形态；并与福建标准砂试验结果进行对比分析。分析对比不同工况下，熔融石英砂透明土含根复合土体的力学性能，并与不含根土体形成对比，得出根系对于土体剪切强度的影响。对比不同含根率复合土体的力学性能，分析得出熔融石英砂透明土含根量的最佳区域。

本文的亮点及难点在于：（1）水族珠配制的透明土中种植植物，并观察其生长状况，并与天然砂土、天然黏土中的植被进行对比分析；（2）研究了熔融石英砂透明土含根复合透明土体的力学性能，获得熔融石英砂透明土含根量的最佳区域，为植物根系可视化研究模型试验提供了参考依据。

关键词：透明土；生态护坡；含根复合土体；三轴试验；力学特性

 

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