Study Shear Strength Characteristics of Gypseous Sandy Soil Using Additives

Abstract

The present study investigated the possibility of enhancing collapsible gypseous soil of Al-Qarma site (with relatively high gypsum content around 50%), which is located in Al-Anbar Governorate, using kaolinite and bentonite as additives. The essential idea is concentrated in mixing these additives with natural soil using different percentages (5, 10, 15 and 20% by soil dry weight) to investigate soil shear strength enhancement. The effect of such additives on soil shear strength parameters, cohesion (C) and angle of internal friction (Φ), and their behavior were studied using direct shear test. The results showed that shear strength parameters of soil sometimes increased and then decreased with increasing additives. Generally, higher shear strength parameters have been obtained from bentonite mixed soil than that of kaolinite mixed soil for the same percentages of additives. It was concluded that bentonite was much more effective in increasing C and reducing Φ than kaolinite. While, kaolinite was much more effective in reducing C than bentonite. It was also concluded that gypseous soil shear strength is improved using such additives (with only 5% kaolinite or with only 20% bentonite) which provide cohesion strength to the soil mass and also acts as a binder agent material. ‫اﻟﺮﻣﻠﯿﺔ‬ ‫ﻟﻠﺘﺮﺑﺔ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻘﺎوﻣﺔ‬ ‫ﺧﺼﺎﺋﺺ‬ ‫دراﺳﺔ‬ ‫ﻣﻀﺎﻓﺎت‬ ‫ﺑﺎﺳﺘﺨﺪام‬ ‫اﻟﺠﺒﺴﯿﺔ‬ ‫اﻟﺨﻼﺻﺔ‬ ‫اﻟﻜﺮﻣﺔ‬ ‫ﻟﻤﻮﻗﻊ‬ ‫اﻻﻧﮭﯿﺎرﯾﺔ‬ ‫اﻟﺠﺒﺴﯿﺔ‬ ‫اﻟﺘﺮﺑﺔ‬ ‫ﺗﺤﺴﯿﻦ‬ ‫اﻣﻜﺎﻧﯿﺔ‬ ‫ﻓﻲ‬ ‫اﻟﺤﺎﻟﯿﺔ‬ ‫اﻟﺪراﺳﺔ‬ ‫ﺗﺒﺤﺚ‬) ‫اﻟﺠﺒﺴﻲ‬ ‫اﻟﻤﺤﺘﻮى‬ ‫ذات‬ ‫ﺑﺤﺪود‬ ‫ﻧﺴﺒﯿﺎ‬ ‫اﻟﻌﺎﻟﻲ‬ 50 (% , ‫اﻷﻧﺒﺎر‬ ‫ﻣﺤﺎﻓﻈﺔ‬ ‫ﺿﻤﻦ‬ ‫اﻟﻮاﻗﻊ‬ , ‫ﻛﻤﻀﺎﻓﺎت‬ ‫واﻟﺒﻨﺘﻮﻧﺎﯾﺖ‬ ‫اﻟﻜﺎؤﻟﯿﻨﺎﯾﺖ‬ ‫ﺑﺎﺳﺘﺨﺪام‬. ‫ان‬ ‫ﻣﺨﺘﻠﻔﺔ‬ ‫ﻣﺌﻮﯾﺔ‬ ‫وﺑﻨﺴﺐ‬ ‫اﻟﻄﺒﯿﻌﯿﺔ‬ ‫اﻟﺘﺮﺑﺔ‬ ‫ﻣﻊ‬ ‫اﻟﻤﻀﺎﻓﺎت‬ ‫ھﺬه‬ ‫ﺑﺨﻠﻂ‬ ‫ﺗﺘﺮﻛﺰ‬ ‫اﻷﺳﺎﺳﯿﺔ‬ ‫اﻟﻔﻜﺮة‬) 5 , 10 , 15 ‫و‬ 20 % ‫اﻟﺠﺎف‬ ‫اﻟﺘﺮﺑﺔ‬ ‫وزن‬ ‫ﻣﻦ‬ (‫ﺗﺤﺴﯿﻦ‬ ‫ﻓﻲ‬ ‫اﻟﺒﺤﺚ‬ ‫أﺟﻞ‬ ‫ﻣﻦ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻘﺎوﻣﺔ‬. ‫د‬ ‫ﺗﻢ‬ ‫ﻋﻠﻰ‬ ‫اﻟﻤﻀﺎﻓﺎت‬ ‫ھﺬه‬ ‫ﺗﺄﺛﯿﺮ‬ ‫راﺳﺔ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻘﺎوﻣﺔ‬ ‫ﻣﻌﺎﻣﻼت‬ , ‫اﻟﺘﻤﺎﺳﻚ‬ ‫ﻗﻮة‬) C (‫اﻟﺪاﺧﻠﻲ‬ ‫اﻻﺣﺘﻜﺎك‬ ‫وزاوﯾﺔ‬) Φ (, ‫ﻓﺤﺺ‬ ‫ﺑﺎﺳﺘﺨﺪام‬ ‫اﻟﺘﺮﺑﺔ‬ ‫وﺳﻠﻮك‬ ‫اﻟﻤﺒﺎﺷﺮ‬ ‫ﻏﯿﺮ‬ ‫اﻟﻘﺺ‬. ‫زﯾﺎدة‬ ‫ﻣﻊ‬ ‫ﺗﺘﻨﺎﻗﺺ‬ ‫ﺛﻢ‬ ‫وﻣﻦ‬ ‫أﺣﯿﺎﻧﺎ‬ ‫ﺗﺰداد‬ ‫ﻟﻠﺘﺮﺑﺔ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻘﺎوﻣﺔ‬ ‫ﻣﻌﺎﻣﻼت‬ ‫ان‬ ‫اﻟﻨﺘﺎﺋﺞ‬ ‫أظﮭﺮت‬ ‫اﻟﻤﻀﺎﻓﺎت‬. ‫ﻣﻌ‬ ‫أﻋﻠﻰ‬ ‫ﻋﻠﻰ‬ ‫اﻟﺤﺼﻮل‬ ‫ﺗﻢ‬ ،‫ﻋﻤﻮﻣﺎ‬ ‫ﺗﻠﻚ‬ ‫ﻣﻦ‬ ‫اﻟﺒﻨﺘﻮﻧﺎﯾﺖ‬ ‫ﻣﻊ‬ ‫اﻟﻤﺨﻠﻮطﺔ‬ ‫ﻟﻠﺘﺮﺑﺔ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻘﺎوﻣﺔ‬ ‫ﺎﻣﻼت‬ ‫اﻟﻤﻀﺎﻓﺔ‬ ‫اﻟﻤﻮاد‬ ‫ﻣﻦ‬ ‫اﻟﻨﺴﺐ‬ ‫وﻟﻨﻔﺲ‬ ‫اﻟﻜﺎؤﻟﯿﻨﺎﯾﺖ‬ ‫ﻣﻊ‬ ‫اﻟﻤﺨﻠﻮطﺔ‬. ‫ﻓﻲ‬ ‫ﺑﻜﺜﯿﺮ‬ ‫ﻓﻌﺎﻟﯿﺔ‬ ‫أﻛﺜﺮ‬ ‫ﻛﺎن‬ ‫اﻟﺒﻨﺘﻮﻧﺎﯾﺖ‬ ‫أن‬ ‫اﺳﺘﻨﺘﺞ‬ PDF created with pdfFactory Pro trial version www.pdffactory.com ‫زﯾﺎدة‬ C ‫وﺗﻘﻠﯿﻞ‬ Φ ‫اﻟﻜﺎؤﻟﯿﻨﺎﯾﺖ‬ ‫ﻣﻦ‬. ‫ﺗﻘﻠﯿﻞ‬ ‫ﻓﻲ‬ ‫ﻓﻌﺎﻟﯿﺔ‬ ‫أﻛﺜﺮ‬ ‫اﻟﻜﺎؤﻟﯿﻨﺎﯾﺖ‬ ‫ﻛﺎن‬ ،‫ﺣﯿﻦ‬ ‫ﻓﻲ‬ C ‫اﻟﺒﻨﺘﻮﻧﺎﯾﺖ‬ ‫ﻣﻦ‬. ‫وﺧﻠﺼﺖ‬ ‫اﻟﻤﻀﺎﻓﺎت‬ ‫ھﺬه‬ ‫ﻣﺜﻞ‬ ‫ﺑﺎﺳﺘﺨﺪام‬ ‫ﺗﺤﺴﯿﻨﮭﺎ‬ ‫ﺗﻢ‬ ‫اﻟﺠﺒﺴﯿﺔ‬ ‫ﻟﻠﺘﺮﺑﺔ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻘﺎوﻣﺔ‬ ‫أن‬ ‫إﻟﻰ‬ ‫أﯾﻀﺎ‬ ‫اﻟﺪراﺳﺔ‬) ‫ﺑﻨﺴﺒﺔ‬ 5 % ‫ﻛﺎؤﻟﯿﻨﺎﯾﺖ‬ ‫ﻓﻘﻂ‬ ‫أ‬ ‫و‬ 20 % ‫ﺑﻨﺘﻮﻧﺎﯾﺖ‬ ‫ﻓﻘﻂ‬ (‫ﻛﻤﺎدة‬ ‫ﻋﻤﻠﮭﺎ‬ ‫اﻟﻰ‬ ‫ﺑﺎﻻﺿﺎﻓﺔ‬ ‫اﻟﺘﻤﺎس‬ ‫ﻗﻮة‬ ‫زﯾﺎدة‬ ‫اﻟﻰ‬ ‫أدت‬ ‫ﺣﯿﺚ‬ ‫راﺑﻄﺔ‬ .